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Cultivar differences in the deterioration of vase-life in cut-flowers of Anthurium andraeanum is determined by mechanisms that regulate water uptake
Scientia Horticulturae 124 (2010) 102–108
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Cultivar differences in the deterioration of vase-life in cut-flowers of Anthurium andraeanum is determined by mechanisms that regulate water uptake W. Elibox, P. Umaharan * Department of Life Sciences, Faculty of Science and Agriculture, The University of the West Indies, St. Augustine Campus, College Rd, Trinidad and Tobago
A R T I C L E I N F O
A B S T R A C T
Article history: Received 6 August 2008 Received in revised form 11 November 2009 Accepted 8 December 2009
Vase-life, average daily water uptake rate and abaxial stomata density were evaluated in 17 anthurium (Anthurium andraeanum Hort.) cultivars over two trials. There were significant cultivar differences for vaselife (14–49 days), 5-day average water uptake rate and abaxial stomata density, in both trials. A progressively stronger correlation coefficient between average daily water uptake rates during the period 25–50 days after initiation of experiment (DAI) and vase-life was observed, indicating that cultivars with longer vase-life were able to maintain above average water uptake rate over a longer period of time and hence delay symptoms of water stress. This was evident in the water uptake rate curves as an inflection, resulting in the levelling off of water uptake rates. The cultivars with long vase-lives achieved steady state water uptake levels faster, and maintained a high steady state water uptake rate for longer durations. The role of vascular occlusion and other senescence factors on water relations and vase-life is discussed. ß 2009 Elsevier B.V. All rights reserved.
Keywords: Vascular occlusion Water stress Steady state water uptake Water relations
1. Introduction Anthurium (Anthurium andraeanum Hort.) is grown for its showy cut-flower, which comprises a spadix containing numerous florets, subtended by a brightly coloured modified leaf, the spathe (Croat, 1988). Anthurium cut-flowers are well known for their long vase-life, which can range from a week to several months depending on the cultivar. Commercially, a vase-life of at least three weeks is required to retain the freshness of cut-flowers through the transportation, distribution and retail chain (Kamemoto and Kuehnle, 1996). Senescence in the anthurium cut-flower begins 8 days after harvest as indicated by a rise in respiration rate, although ethylene production remains low throughout its post-harvest life (Paull et al., 1985). The symptoms of end of vase-life viz. spathe wilting, spathe or spadix darkening, loss of spathe glossiness and spathe blueing are primarily the result of water stress (Paull and Goo, 1985; Mujaffar and Sankat, 2003). Anthurium cut-flowers can maintain a positive water balance for an extended period compared with other flowers (Mujaffar and Sankat, 2003), since the relatively few stomatal openings on the colourful spathe, and abundant layers of waxy cuticle on both the spathe and peduncle prevent significant waterloss (Watson and Shirakawa, 1967). Water loss in anthurium cut-flowers therefore occurs primarily through the numerous tiny flowers on the spadix.
* Corresponding author. Tel.: +868 6622002x3108; fax: +868 6635241/6639686. E-mail address: [email protected] (P. Umaharan). 0304-4238/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.scienta.2009.12.005
In a recent study (Elibox and Umaharan, 2008), although only cultivar differences in abaxial stomata density (spathe) was found to affect cut-flower deterioration among a range of morphological and anatomical features of the anthurium cut-flower examined, it explained only a small proportion of cultivar variation in vase-life. van Doorn (1999) showed that vascular occlusion that results in reduced hydraulic conductivity at the peduncle base contributes to the water stress induced senescence symptoms in anthurium. Dole and Schnelle (1999) showed that vase-life can be prolonged by excising away the lowest 5 cm segment of the peduncle during their vase-life study, providing support for the above notion. Although previous studies (Shirakawa et al., 1964; Paull and Goo, 1985; Sankat and Mujaffar, 1994) point to impeded water uptake as a possible mechanism of loss of vase-life, cultivar differences have not been investigated in a range of cultivars with varying vase-lives to determine the relative importance of this in cutflower deterioration in anthurium. The objective of this study was to evaluate the water uptake behaviour in a range of anthurium cultivars with the objective of establishing a relationship between water uptake patterns and vase-life. 2. Material and methods 2.1. Location Vase-life experiments were conducted in two trials, Trial 1 (March–May, 2001) and Trial 2 (September–October, 2001) at the laboratories of the University of the West Indies, St. Augustine,
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Table 1 The 17 anthurium cultivars evaluated in the vase-life study and their stomata numbers on the abaxial surface in Trial 1 (March) and Trial 2 (September). Cultivars
Origin
Spathe colour
Acropolis Cuba Fantasia Pierrot Evergreen Local Pink Lydia Spirit Mirjam Success Tropical Honduras Midori Tequila Fla Range Terra Venus
The Netherlands The Netherlands The Netherlands The Netherlands The Netherlands Trinidad The Netherlands The Netherlands The Netherlands The Netherlands The Netherlands The Netherlands Hawaii The Netherlands The Netherlands The Netherlands The Netherlands
White White White White White with green lobes Pink Pink Pink Red Red Red Red and green Green Green Orange Bronze Coral
Sig. (P) Mean SEM LSD (0.05) CVwithin (%) Genotypic CV (%)
Trinidad. The cut-flowers were collected from a commercial farm, Kairi Blooms Ltd, in Arima, Trinidad, where anthurium is cultivated under uniform cultural and management conditions. 2.2. Cultivars and cultural conditions Cut-flowers used in the study were obtained from 3- to 4-yearold plants of 17 cultivars (Table 1). The cultivars were maintained at a spacing of 0.45 m 0.4 m on beds (23 m 1.2 m) made of pulverized coconut husk. The beds were fertilised with either triple super phosphate (Chemos GmBH, Regenstauf, Germany) or 12N11P-13K (Norsk Hydro Olje AB, NYBRO, Sweden), every month at a rate of approximately 0.45 kg per bed. Urea (National Agro, Port of Spain, Trinidad) and di-ammonium phosphate (Brenntag, Dominican Republic) were applied as necessary at a rate of 0.23 kg per bed. The pH of the bed was maintained at 5.6 through liming (Limestone, Trincarb, Trinidad). The plants were irrigated once daily for 15 min by overhead irrigation. 2.3. Harvesting and transport of cut-flowers Cut-flowers with no scratches, no deformities and straight peduncles were harvested at the 3/4 mature stage of the spadix. The cut-flowers were harvested with a sharp, sterile scalpel, packed in boxes containing wet shredded paper and transported to the University laboratory in an air-conditioned vehicle. 2.4. Experimentation In Trial 1, three cut-flowers from each of the 17 cultivars were placed separately in sterile, 250 ml measuring cylinders containing 210 ml of sterile distilled water, and maintained in a laboratory setting (11 h white fluorescent light; 23.8 8C; 73.5% RH). Before placing the cut-flowers into the cylinder the base of the peduncles were freshly cut under water at an angle of 458 using a sharp, sterile scalpel. The experiment was arranged in a completely randomised design with 3–8 replications per cultivar, depending on the availability of spathes of uniform maturity stage. The cylinders were covered with a cellophane wrap to prevent evaporation.
Abaxial stomata number (mm
2
)
Vase-life (days)
March
September
March
September
11.0 1.9 16.4 5.0 25.7 2.2 2.8 9.6 6.6 2.6 3.3 4.2 5.9 4.1 1.8 5.1 5.3
14.6 2.6 16.2 6.5 24.5 2.5 4.3 – 6.9 5.6 6.2 4.2 6.2 11.2 2.8 6.6 5.6
18 49 19 37 14 17 26 15 18 16 24 45 34 33 33 40 15
16 41 14.2 34.3 21 21 15 – 15 19 14 37.7 48.7 21.5 22 30 18
0.001 6.7 1.05 2.98 15.7 92.7
0.001 7.4 0.954 2.71 17.7 80.4
0.001 26.6 2.19 6.18 15.9 43.0
0.001 22.8 2.26 6.43 16.2 45.6
Cut-flowers were monitored for a period until loss of vase-life occurred. Vase-life was determined by whichever of the following occurred first: spadix browning/necrosis, spathe floppiness, spathe browning/necrosis, spathe discoloration, and loss of lustre/glossiness of spathe. Cylinders were topped to the original water level at the same time each day using a dispenser, and the amount of water required was noted as the water uptake for that day. Five-day mean water uptake rates (WUR) were calculated (per cut-flower basis) for each replicate of each of the 17 cultivars, for the study period. The experiment was continued until all the cultivars began to show the signs of deterioration. The water uptake curves based on 5-day mean WUR were plotted against time for each replicate plot of each cultivar and the time to inflection on the water loss curve (time to steady state water uptake) as well as the duration of steady state water uptake (SSW) and the rate of SSW were determined from the WUR curve. Abaxial stomata density was determined on three randomly selected spathes per cultivar. Four 1.5 0.5 cm pieces were cut from each spathe and placed in a clearing solution in a petri dish. The clearing solution was prepared by adding 15 g of NaOH pellets to 500 ml of water and 500 ml of 95% ethanol. The solution was replaced routinely as it became pigmented. Cleared sections were mounted on slides, stained with toluidine blue and warmed for 2 min on a slide warmer at 40 8C. Stomata density was enumerated for each section based on four views at 100 magnification using a light microscope (Euromex, the Netherlands). From this the mean number of stomata mm 2 on the abaxial spathe surface of each cultivar was calculated. The vase-life experiment described was repeated in Trial 2 using 16 of the 17 cultivars used in Trial 1 (except ‘Spirit’, due to unavailability of adequate cut-flowers) under the same conditions. Three replicates with three cut-flowers per replicate were evaluated for each cultivar. 2.5. Data analysis One-way ANOVA was conducted using NCSS (2001 version, Kaysville, Utah, USA) to determine the significance of cultivar
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differences for the 5-day WUR, time to SSW, duration of SSW, the SSW rate and vase-life. Pearson’s product moment correlation analysis (NCSS, 2001) was carried out to determine the correlation coefficients between the various water uptake parameters (5-day mean WUR, days to SSW, duration of SSW and SSW rate) and vase-life, stomata density and spathe colour. Step-wise multiple regression analysis (NCSS, 2001) was conducted to determine the proportion of variation in vase-life determined by the various water uptake parameters. 3. Results 3.1. Stomata density and vase-life There were significant (P < 0.001) cultivar differences in stomata density (mm 2) between cultivars, varying between 1.8 in cultivar ‘Fla Range’ and 25.7 in cultivar ‘Evergreen’ in Trial 1; and between 2.5 in ‘Local Pink’ and 24.5 in ‘Evergreen’ in Trial 2 (Table 1). Similarly there were significant (P < 0.001) cultivar differences in vase-life in both Trials 1 and 2 (Table 1), with vaselife varying between 14 (‘Evergreen’) and 49 days (‘Cuba’) among the cultivars tested in Trial 1, and between 14 (‘Tropical’ and ‘Fantasia’) and 49 days (‘Midori’) in Trial-2 (Table 2). The vase-life on average was 3 days longer in Trial 1 than in Trial 2. The correlation coefficient between vase-lives in Trials 1 and 2 was 0.72. 3.2. Average water uptake rate 3.2.1. Trial 1 There were significant cultivar differences (P < 0.001) between 5-day mean WUR from 5 to 45 days (Table 2). The mean WUR over all cultivars showed a steady decline up to 25 days after initiation (DAI) but showed an inflection (Fig. 1), which maintained WUR up to 40 DAI, but continued to decline rapidly thereafter. Table 3 shows that the time at which the inflection occurred (days to SSW),
Table 2 Five-day average water uptake rate (ml day Cultivar
Mirjam Venus Spirit Pierrot Fla Range Midori Terra Cuba Tropical Honduras Lydia Evergreen Success Tequila Acropolis Fantasia Local Pink a
Sig. level (P<) Mean LSD (0.05) CV within (%) Genotypic CV (%) Correlation to stomata no. Correlation to vase-life a
Significance.
) per cut-flower for 17 cultivars of anthurium over a 55-day period, post-harvesting, in a vase-life study (Trial 1).
10 1.33 1.40 1.50 1.65 0.95 2.40 2.26 2.19 1.14 1.27 0.93 2.79 1.13 1.11 1.01 1.51 2.26
0.001 1.58 0.47 0.20 272 0.40 0.11
3.2.2. Trial 2 There were significant cultivar differences (P 0.001) for 5-day mean WUR in Trial 2 (Table 4). Cultivars ‘Acropolis’, ‘Evergreen’, ‘Fantasia’, ‘Fla Range’, ‘Lydia’, ‘Mirjam’, ‘Success’, ‘Tropical’ and ‘Venus’ had WUR below the general mean of cultivars, while cultivar ‘Cuba’, ‘Midori’, ‘Pierrot’, ‘Tequila’ and ‘Terra’ had above average WUR. For the cultivar, ‘Honduras’ initial WUR was lower than the general mean, but by day 40 had values greater than the general mean. Again, cultivars with long vase-lives (>35 days) such as ‘Cuba’, ‘Pierrot’, ‘Midori’, ‘Honduras’ and ‘Terra’ took 35–50 days to experience a 65% decrease in WUR, whereas cultivars with short vase-lives (<20 days) took 10–30 days to experience a similar decrease (Table 4). By day 50, 62.5% of the cultivars ceased water uptake entirely. The time at which the inflection occurred on the water uptake curve, the duration of SSW and the SSW rate varied significantly (P < 0.001) among the 16 anthurium cultivars tested in Trial 2 and showed similar trends to Trial 1 (data not presented).
1
Average transpiration rate (ml day 5
the duration of SSW and the average SSW rates varied significantly (P < 0.001) among the 17 anthurium cultivars. As a result, the cultivars showing above average WUR varied with time. For instance, cultivars with long vase-lives (>35 days) such as ‘Cuba’, ‘Pierrot’, ‘Honduras’ and ‘Terra’ took 40–55 days to experience a 65% decrease in WUR, whereas cultivars with short vase-lives (<20 days) took 10–30 days to experience a similar decrease in WUR (Table 2). Table 3 shows that ‘Cuba’, ‘Honduras’, ‘Terra’, ‘Tequila’, ‘Pierrot’, ‘Fla Range’ and ‘Midori’ maintained a relatively higher WUR for a longer time (20–35 days). The mechanism that maintains a relatively high steady state was not triggered until some level of decline in WUR had occurred in the cultivars. There is some variation in the timing of this mechanism. Often the mechanism was triggered too late so that the cutflowers would have already started showing desiccation symptoms.
15 0.90 0.81 1.12 1.03 0.60 1.52 1.42 1.16 0.63 0.89 0.73 1.29 0.64 0.71 0.70 0.91 1.48
0.001 0.97 0.28 0.21 315 0.22 0.15
1
) at day 20
0.62 0.61 0.88 0.79 0.44 1.24 1.10 0.98 0.63 0.78 0.58 0.84 0.64 0.76 0.58 0.80 1.26 0.001 0.80 0.32 0.29 338 0.03 0.24
0.53 0.48 0.86 0.69 0.40 1.13 1.30 0.91 0.58 0.66 0.51 0.42 0.58 0.84 0.42 0.51 0.99 0.001 0.69 0.31 0.30 260 0.31 0.46
25 0.49 0.48 0.76 0.68 0.33 0.97 1.13 0.74 0.39 0.51 0.42 0.26 0.60 0.73 0.36 0.42 0.68 0.001 0.59 0.30 0.34 250 0.36 0.45
30
35 0.48 0.47 0.60 0.66 0.40 0.82 1.11 0.71 0.30 0.50 0.24 0.23 0.53 0.82 0.39 0.20 0.59
0.001 0.53 0.36 0.46 219 0.41 0.53
0.35 0.18 0.56 0.68 0.47 0.82 1.16 0.73 0.27 0.44 0.40 0.24 0.64 0.87 0.33 0.20 0.67 0.001 0.53 0.36 0.48 196 0.43 0.57
40
45 0.25 0.09 0.24 0.70 0.44 0.70 0.87 0.80 0.11 0.59 0.29 0.31 0.62 0.84 0.22 0.24 0.62
0.001 0.47 0.32 0.47 176 0.37 0.70
0.20 0.13 0.11 0.69 0.44 0.59 0.80 0.70 0.19 0.53 0.07 0.30 0.41 0.67 0.30 0.19 0.38 0.001 0.39 0.32 0.57 169 0.29 0.78
50
55
0.17 0.13 0.10 0.48 0.37 0.28 0.38 0.70 0.00 0.54 0.00 0.00 0.00 0.44 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.07 0.17 0.24 0.56 0.00 0.50 0.00 0.00 0.00 0.50 0.00 0.00 0.00
(NS) 0.21 – – 91 0.40 0.91
(NS) 0.12 – – 59 0.30 0.80
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105
Fig. 1. Mean 5-day water uptake (ml) over all anthurium cultivars (diamonds) and mean 5-day water uptake (ml) for individual cultivar (squares): (a) Cuba, (b) Honduras, (c) Fantasia and (d) Honduras evaluated in Trial 1.
3.3. Character correlation and regression analysis Correlation coefficients between vase-life and 5-day mean WUR during the period 5–55 DAI increased from 0.11 to 0.91 in Table 3 Days to steady state water uptake and duration (days), transpiration (ml) at steady state and vase-life of 17 anthurium cultivars evaluated in Trial 1. Cultivar
a
Mirjam Venus Spirit Pierrot Fla Range Midori Terra Cuba Tropical Honduras Lydia Evergreen Fantasia Local pink Acropolis Tequila Success
15 20 30 20 30 15 15 15 15 25 25 20 30 25 20 15 20
15 10 5 25 25 20 30 35 10 30 15 20 15 15 25 30 20
c Sig. (P) Mean SEM LSD (0.05) Genotypic CV (%)
0.001 20.9 1.28 3.63 27.1
0.001 20.3 1.99 5.63 41.3
a b c
Days to SSW
Duration of bSSW (days)
Rate of SSW (ml day 1) 0.53 0.48 0.58 0.7 0.47 0.97 1.1 0.8 0.63 0.55 0.42 0.29 0.2 0.62 0.33 0.84 0.59 0.001 0.59 0.045 0.13 39.2
Days to SSW—days to steady state water uptake in water uptake curve. SSW—steady state water uptake. Significance.
Trial 1 (Table 2; Fig. 2) and from 0.24 to 0.85 in Trial 2 (Table 4). The correlation coefficients between vase-life and average WUR were significant from day 30 to day 50 (r = 0.53–0.91; P < 0.05) in Trial 1 and between day 25 and day 50 (r = 0.57–0.85; P < 0.05,) in Trial 2. The results indicate that the ability of an anthurium cultivar to maintain WUR later in the life of the cut-flower was correlated to vase-life. Although not significant (P > 0.05), interestingly, correlation between average WUR and stomata number showed a negative trend between 20 and 55 days in Trial 1 (Table 2), and between 25 and 50 days in Trial 2 (Table 4). In Trial 1, correlation coefficients between vase-life and duration of SSW (r = 0.78; P 0.01) and vase-life and SSW rate (r = 0.60; P < 0.05) were significant, but not between vase-life and days to SSW (r = 0.27; P > 0.05) (Table 5). Days to SSW, SSW rate and duration of SSW explained 7%, 36% and 61% of the variation in vase-life, respectively. Step-wise multiple regression analysis showed that SSW rate and duration of SSW explained 71% of the variation in vase-life in Trial 1. In Trial 2, vase-life showed significant correlation with days to SSW (r = 0.59; P < 0.05), duration of SSW (r = 0.69; P < 0.01), and with SSW rate (r = 0.77; P < 0.001). Days to SSW, SSW rate, duration of SSW rate explained 35%, 59% and 48% of the variation in vase-life, respectively. Again step-wise multiple regression analysis showed that SSW rate and duration of SSW explained 73% of variation and all three attributes (days to SSW, SSW rate and duration of SSW) together explained 81% of the variation in vaselife. These results again showed that the ability of an anthurium cultivar to maintain water uptake rates later in the life of the cutflower was correlated to vase-life. Abaxial stomata density did not correlate significantly with average daily water uptake (Table 4), days to SSW, duration of SSW,
W. Elibox, P. Umaharan / Scientia Horticulturae 124 (2010) 102–108
106 Table 4 Five-day means for water uptake (ml day Cultivar
1
) per cut-flower for a 50-day period, post-harvest for 16 cultivars of anthurium in a vase-life study (Trial 2).
Average transpiration rate (ml day 5
10
15
1
) at day 20
25
30
35
40
Acropolis Cuba Evergreen Fantasia Fla Range Honduras Local Pink Lydia Midori Mirjam Pierrot Success Tequila Terra Tropical Venus
3.67 5.20 5.27 4.67 4.53 3.33 8.60 2.87 4.93 3.2 4.87 2.87 5.00 10.0 3.47 4.27
2.07 3.20 3.73 2.53 2.80 2.33 5.27 1.80 3.13 2.07 3.13 1.73 3.20 6.40 2.27 2.67
2.00 2.80 3.80 1.27 2.13 2.13 3.93 1.33 3.00 1.53 2.33 1.13 3.07 5.40 1.47 2.60
1.53 2.80 3.53 1.40 1.47 1.73 3.07 1.23 2.67 1.13 2.27 1.40 2.93 4.80 1.07 1.93
1.40 2.60 1.60 0.67 1.20 1.47 2.33 1.07 2.47 1.20 1.73 0.93 2.53 3.93 0.67 1.73
0.87 2.73 0.67 0.40 1.47 1.60 1.93 0.53 2.33 1.27 1.87 1.20 2.73 3.87 0.40 1.27
0.40 2.67 0.67 0.67 1.47 1.33 1.47 0.40 2.13 0.73 2.00 1.33 2.33 3.47 0.40 1.40
0.44 2.13 0.11 0.67 0.78 1.24 0.89 0.89 1.80 0.78 2.00 0.44 1.60 2.27 0.56 0.67
a
0.001 4.8 1.23 40.8 0.04 0.24
0.001 3.02 0.82 41.4 0.02 0.26
0.001 2.5 0.88 46.4 0.09 0.38
0.001 2.19 1.04 47.5 0.17 0.44
0.001 1.72 0.92 50.3 0.16 0.57
0.001 1.57 0.73 62.0 0.35 0.63
0.001 1.43 0.66 63.0 0.34 0.67
0.001 1.08 0.76 62.4 0.42 0.75
Sig. (P) Mean LSD (0.05) Genotypic CV (%) Correlation to stomata no. Correlation to vase-life a
45
50 0.00 2.20 0.00 0.00 0.00 1.07 0.00 0.00 1.43 0.00 1.07 0.00 1.80 0.83 0.00 0.00
0.001 0.53 0.87 145.0 0.22 0.79
0.00 2.20 0.00 0.00 0.00 0.93 0.00 0.00 1.53 0.00 1.07 0.00 1.27 0.67 0.00 0.00 0.001 0.48 0.75 148.3 0.25 0.85
Significance.
Table 5 Pearson’s correlation coefficients between water uptake parameters (days to SSW, duration of SSW and SSW rate) and vase-life, abaxial stomata density and 5-day mean water uptake over the period 5–50 days in Trials 1 and 2. Trial 1 Days to SST Vase-life Abaxial stomata density Days to SST Duration of SST Transpiration day 5 Transpiration day 10 Transpiration day 15 Transpiration day 20 Transpiration day 25 Transpiration day 30 Transpiration day 35 Transpiration day 40 Transpiration day 45 Transpiration day 50 Transpiration day 55 a
0.27 0.16 1.00 0.34 0.26 0.16 0.20 0.35 0.37 0.48 0.37 0.34 0.44 0.27 0.32
Trial 2 Duration of SST 0.78 0.18 0.34 1.00 0.15 0.07 0.14 0.27 0.27 0.47 0.53 0.76 0.85 0.76 0.75
SST Rate 0.60 0.53 0.60 0.40 0.33 0.45 0.57 0.87 0.90 0.93 0.89 0.76 0.74 0.57 0.51
Days to SST
Duration of SST
0.59 0.20 1.00 0.67 0.27 0.30 0.35 0.45 0.46 0.44 0.43 0.53 0.74 0.73 a –
0.69 0.25 0.67 1.00 0.04 0.03 0.09 0.18 0.33 0.39 0.43 0.50 0.85 0.86 –
SST Rate 0.77 0.07 0.79 0.46 0.58 0.60 0.59 0.69 0.78 0.82 0.82 0.87 0.79 0.75 –
In Trial 2, 5-day transpiration was monitored up to 50 days only.
SSW rate or vase-life (P > 0.05) in Trial 2, but was correlated to SSW rate alone in Trial 1 (Table 5). 4. Discussion The relatively long vase-life and the large cultivar variation in vase-life in anthurium have attracted considerable interest. There was more than a 3.5-fold variation (14–49 days) in vase-life among the anthurium cultivars tested. Cultivars ‘Cuba’, ‘Honduras’, ‘Pierrot’, ‘Terra’ and ‘Midori’ had consistently long vase-lives in both trials. In contrast, ‘Evergreen’, ‘Mirjam’, ‘Acropolis’ and ‘Venus’ had consistently short vase-lives. Cultivar differences in vase-life have also been reported in carnation (Wu et al., 1991), gerbera (Wernett et al., 1996) and roses (Ichimura et al., 2002). 4.1. Water stress and loss of vase-life Fig. 2. Correlation coefficients between average daily water uptake rates of cutflowers of 17 anthurium cultivars measured at 5-day intervals and vase-life (Trial 1).
Many researchers have shown that symptoms associated with the end of vase-life in anthurium are typical of water stress
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(Shirakawa et al., 1964; Paull, 1982), which is in agreement with this study. The end of vase-life was associated with wilting, loss of glossiness, darkening or bluing of the spathe, as has been observed in previous studies (Paull, 1982; Paull and Goo, 1985). Water stress is a function of the water content at harvest, and the rates of water uptake and water loss after harvest (Halevy and Mayak, 1981; Meman and Dabhi, 2006). Mujaffar and Sankat (2003) showed using one cultivar of anthurium that water stress symptoms appear when the balance between transpiration loss and water uptake exceed 1.5. Consequently, spadix removal (Paull and Goo, 1985) or waxing of anthurium cut-flowers (Paull and Goo, 1985; Mujaffar and Sankat, 2003), that aims to reduce transpiration rate (Mujaffar and Sankat, 2003), have been shown to improve vase-life in anthurium. Similar to the findings of a previous study (Elibox and Umaharan, 2008), this study showed that vase-life was not significantly correlated to abaxial stomatal density, which is usually a function of transpiration losses. Instead vase-life was strongly correlated to water uptake rate, which indicates that the latter may have a more important role in determining the water balance status of anthurium cultivars. That WUR may have an important role on the water status of anthurium cut-flowers is evident from a number of studies, Dole and Schnelle (1999) showed that vase-life can be prolonged by excising away the lowest 5 cm segment of the peduncle during their vase-life study, which maintains WUR for longer periods of time. Low temperature storage was also shown to prolong vase-life by retarding both vascular occlusion and transpiration rate (Mujaffar and Sankat, 2003), while pulsing with BA presumably retards vascular occlusion in extending vase-life (Paull and Goo, 1985). The progressively stronger correlation between vase-life and mean daily WUR during the 25–50 day period in Trials 1 and 2, indicate that cultivars that maintained above average WUR over the 50-day period had a longer vase-life. This suggests that cultivar differences in vase-life may be mediated though differences in their ability to maintain a high WUR, particularly during this period of the vase-life experiment. Cultivar differences in the ability to maintain high WUR was evident in the WUR-time curve as an inflection, resulting in the levelling off of water uptake rates. The study showed that cultivars which were able to achieve SSW earlier and maintain a high SSW for a longer duration were able to prolong their vase-life. In Trial 1, duration of SSW and SSW rate explained 71% of the variation in vase-life, while in Trial 2, days to SSW, duration of SSW and SSW rate together explained 81% of the variation in vase-life among cultivars. These results indicate a significant role for WUR in regulating the water status and ultimately vase-life in anthurium. 4.2. Vascular occlusion The mean WUR for all cultivars was initially high, but steadily decreased over time, consistent with observations by Paull and Goo (1985). This decline in WUR in cut-flowers in general is attributed to the decrease in hydraulic conductivity at the peduncle base due to vascular occlusion (de Witte and van Doorn, 1992; van Doorn et al., 1995). Vascular occlusion as a mechanism for water stress induced senescence in anthurium has been also suggested by Paull and Goo (1985). There was evidence from this study that the rate of decrease in WUR, resulting from vascular occlusion as shown by Paull and Goo (1985), varied with cultivars. Cultivars with a vase-life of over 35 days took 40–55 days in Trial 1 and 35–50 days in Trial 2, to experience a 65% decline in WUR. In contrast, cultivars with vaselives of less than 20 days took 10–30 days in both Trials 1 and 2 to experience a similar 65% reduction in WUR This suggests that the vascular occlusion process may have been slow and incomplete in the cultivars with longer vase-life. This is in agreement with the
107
findings of Salvi et al. (1997). In conclusion, the results suggest that water uptake rates are maintained, albeit at a lower rate, in some cultivars despite the vascular occlusion process (van Doorn et al., 1995; Paull and Goo, 1985), which allows these cultivars to maintain water status, and thereby extend their vase-life. Paull and Goo (1985) suggested that wound induced ethylene production possibly accounted for the vascular occlusion process, since other known factors, such as occlusion due to air-blockage (Teshigahara, 1982) or bacteria (Durkin and Put, 1995; Noordegraaf, 1999) could not be attributed to this process. 4.3. Mechanisms governing cultivar differences Noordegraaf (1999), van Doorn (1999) and Mujaffar and Sankat (2003) have showed that water uptake and loss by transpiration must be balanced, or otherwise, the cut-flowers will wilt and show symptoms of water shortage. The two stages of WUR that reflect vase-life of the anthurium cut-flower are: (i) Phase 1—phase of declining WUR rate (initial period of 0–20 days), which is a function of the rapidity and degree of vascular occlusion (days to SSW and SSW rate) and (ii) Phase 2—phase of steady state water uptake during the subsequent period (duration of SSW), may be function of other senescence factors associated with membrane integrity. The WUR curves showed various patterns (reflecting differences in days to SSW, SSW rate and SSW duration) among cultivars with long vaselives, indicating that the mechanism/s governing cultivar differences in vase-life may differ with cultivars. Elibox and Umaharan (2008) contended that at least part of the cultivar variation in vase-life in anthurium was attributed to abaxial stomata number and spathe colour. They argued that while abaxial stomatal number was related to transpiration losses, the effect of spathe colour may determine other senescence factors. The dominant pigments in white cultivars are flavones (Iwata et al., 1985), which have a strong and proven antioxidant capacity (Rice-Evans et al., 1997) and are excellent free radical scavengers. Furthermore, flavones may be involved in maintaining membrane integrity or they may have a role in protection from photo-inhibition (Gould et al., 1995; Gould et al., 2000; Dodd et al., 1998). It is proposed that a balance between factors affecting water uptake which is determined by the timing, extent and duration of vascular occlusion, and those that affect water loss (e.g. affecting stomatal regulation) may contribute to cut-flower senescence in anthurium. The study shows that water uptake parameters explain a large proportion of cultivar variation in vase-life, indicating that waterloss plays a prominent role in determining water status and thus vase-life of anthurium cutflowers. Understanding the mechanism of differences in uptake would provide opportunities for extending vase-life. Further studies are being conducted to determine the mechanisms. Acknowledgements This study was funded by the EUFORUM/CARIFORUM under the Caribbean Agricultural Technology Fund (CARTF) programme. We thank the management and staff of Kairi Blooms Farm for providing the facilities for the research. References Croat, T.B., 1988. Ecology and life forms of Araceae. Aroideana 11, 4–55. de Witte, Y., van Doorn, W.G., 1992. The mode of action of bacteria in the vascular occlusion of cut rose flowers. Acta Hort. 298, 155–170. Dodd, I.C., Critchley, C., Woodall, G.S., Stewart, G.R., 1998. Photoinhibition in differently coloured juvenile leaves of Syzygium species. J. Exp. Bot. 49, 1437–1445. Dole, J., Schnelle, M.A., 1999. The Care and Handling of Cut Flowers. Okla State Coop. Ext. Serv., F-6426.
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Durkin, D.J., Put, H.M.C., 1995. Scanning electron microscope observations of the cut surface of Rosa ‘Kardinal’ influenced by vase water composition. Acta Hort. 405, 97–100. Elibox, W., Umaharan, P., 2008. Morphophysiological characteristics associated with vase life of cut flowers of Anthurium. HortScience 43 (3), 825–831. Gould, K.S., Kuhn, D.N., Lee, D.W., Oberbauer, S.F., 1995. Why leaves are sometimes red. Nature 378, 241–242. Gould, K.S., Markham, K.R., Smith, R.H., Goris, J.J., 2000. Functional role of anthocyanins in the leaves of Quintinia serrata A. Cunn. J. Exp. Bot. 51 (347), 1107– 1115. Halevy, A.H., Mayak, S., 1981. Senescence and postharvest physiology of cut flowers: part 2. Hort. Rev. 3, 59–143. Ichimura, K., Kawabata, Y., Kishimoto, M., Goto, R., Yamada, K., 2002. Variation with the cultivar in the vase life of cut rose flowers. Bull. Natl. Inst. Flor. Sci. 2, 9–20. Iwata, R.Y., Tang, C.S., Kamemoto, H., 1985. Concentration of anthocyanins affecting spathe colour in anthuriums. J. Am. Soc. Hort. Sci. 110, 383–385. Kamemoto, H., Kuehnle, A.R., 1996. Breeding Anthuriums in Hawaii. University of Hawaii Press, Honolulu. Meman, M.A., Dabhi, K.M., 2006. Effect of different stalk lengths and certain chemical substances on vase life of gerbera (Gerbera jamesonii Hook.) cv. ‘Savana Red’ J. Appl. Hort. 8 (2), 147–150. Mujaffar, S., Sankat, C.K., 2003. Effect of waxing on the water balance and keeping qualities of cut anthuriums. Int. Agrophys. 17, 77–84. NCSS, 2001. Number Crunching Statistical System. NCSS, Kaysville, UT, USA. Noordegraaf, C.V., 1999. Problems of post harvest management in cut flowers. Acta Hort. 482, 53–58. Paull, R.E., 1982. Anthurium (Anthurium andraeanum Andre´) vaselife evaluation criteria. HortScience 17 (4), 606–607.
Paull, R.E., Chen, N.J., Deputy, J., 1985. Physiological changes associated with senescence of cut anthurium flowers. J. Am. Soc. Hort. Sci. 110, 156–162. Paull, R.E., Goo, T.T.C., 1985. Ethylene and water stress in the senescence of cut anthurium flowers. J. Am. Soc. Hort. Sci. 110, 84–88. Rice-Evans, C.A., Miller, N.J., Paganga, G., 1997. Antioxidant properties of phenolic compounds. Trends Plant Sci. 2, 152–159. Salvi, B.R., Valsalakumari, P.K., Rajeevan, P.K., Geetha, C.K., 1997. Effect of holding solutions on cut anthurium flowers. Hort. J. 10 (2), 65–72. Sankat, C.K., Mujaffar, S., 1994. Water balance in cut Anthurium flowers in storage and its effect on quality. Acta Hort. 368 (2), 723–732. Shirakawa, T., Edolph, R.D., Watson, D.P., 1964. N-6-Benzyladenine effects on chilling injury, respiration and keeping quality of Anthurium andraeanum. Proc. Am. Soc. Hort. Sci. 85, 642–646. Teshigahara, W., 1982. Ikebana, a New Illustrated Guide to Mastery. Kodansha International Ltd, Tokyo, Japan. van Doorn, W.G., de Witte, Y., Harkema, H., 1995. Effect of high numbers of exogenous bacteria on the water relations and longevity of cut carnation flowers. Postharv. Biol. Technol. 6, 111–119. van Doorn, W.G., 1999. Vascular occlusion in cut flowers. I. General principles and recent advances. Acta Hort. 482, 59–63. Watson, D.P., Shirakawa, T., 1967. Gross morphology related to shelf-life of Anthurium flowers. Hawaii Farm Sci 16, 1–3. Wernett, H.C., Wilfret, G.J., Sheehan, T.J., Marousky, F.J., Lyrene, P.M., Knauft, D.A., 1996. Postharvest longevity of cut-flower Gerbera. I. Response to selection for vase life of components. J. Amer. Soc. Hort. Sci. 121, 216–221. Wu, M.J., Van Doorn, W.G., Reid, M.S., 1991. Variation in the senescence of carnation (Dianthus caryophyllus L.) cultivars. I. Comparison of flower life, respiration and ethylene biosynthesis. Sci. Hort. 48, 99–107.
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Cultivar differences in the deterioration of vase-life in cut-flowers of Anthurium andraeanum is determined by mechanisms that regulate water uptake W. Elibox, P. Umaharan * Department of Life Sciences, Faculty of Science and Agriculture, The University of the West Indies, St. Augustine Campus, College Rd, Trinidad and Tobago
A R T I C L E I N F O
A B S T R A C T
Article history: Received 6 August 2008 Received in revised form 11 November 2009 Accepted 8 December 2009
Vase-life, average daily water uptake rate and abaxial stomata density were evaluated in 17 anthurium (Anthurium andraeanum Hort.) cultivars over two trials. There were significant cultivar differences for vaselife (14–49 days), 5-day average water uptake rate and abaxial stomata density, in both trials. A progressively stronger correlation coefficient between average daily water uptake rates during the period 25–50 days after initiation of experiment (DAI) and vase-life was observed, indicating that cultivars with longer vase-life were able to maintain above average water uptake rate over a longer period of time and hence delay symptoms of water stress. This was evident in the water uptake rate curves as an inflection, resulting in the levelling off of water uptake rates. The cultivars with long vase-lives achieved steady state water uptake levels faster, and maintained a high steady state water uptake rate for longer durations. The role of vascular occlusion and other senescence factors on water relations and vase-life is discussed. ß 2009 Elsevier B.V. All rights reserved.
Keywords: Vascular occlusion Water stress Steady state water uptake Water relations
1. Introduction Anthurium (Anthurium andraeanum Hort.) is grown for its showy cut-flower, which comprises a spadix containing numerous florets, subtended by a brightly coloured modified leaf, the spathe (Croat, 1988). Anthurium cut-flowers are well known for their long vase-life, which can range from a week to several months depending on the cultivar. Commercially, a vase-life of at least three weeks is required to retain the freshness of cut-flowers through the transportation, distribution and retail chain (Kamemoto and Kuehnle, 1996). Senescence in the anthurium cut-flower begins 8 days after harvest as indicated by a rise in respiration rate, although ethylene production remains low throughout its post-harvest life (Paull et al., 1985). The symptoms of end of vase-life viz. spathe wilting, spathe or spadix darkening, loss of spathe glossiness and spathe blueing are primarily the result of water stress (Paull and Goo, 1985; Mujaffar and Sankat, 2003). Anthurium cut-flowers can maintain a positive water balance for an extended period compared with other flowers (Mujaffar and Sankat, 2003), since the relatively few stomatal openings on the colourful spathe, and abundant layers of waxy cuticle on both the spathe and peduncle prevent significant waterloss (Watson and Shirakawa, 1967). Water loss in anthurium cut-flowers therefore occurs primarily through the numerous tiny flowers on the spadix.
* Corresponding author. Tel.: +868 6622002x3108; fax: +868 6635241/6639686. E-mail address: [email protected] (P. Umaharan). 0304-4238/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.scienta.2009.12.005
In a recent study (Elibox and Umaharan, 2008), although only cultivar differences in abaxial stomata density (spathe) was found to affect cut-flower deterioration among a range of morphological and anatomical features of the anthurium cut-flower examined, it explained only a small proportion of cultivar variation in vase-life. van Doorn (1999) showed that vascular occlusion that results in reduced hydraulic conductivity at the peduncle base contributes to the water stress induced senescence symptoms in anthurium. Dole and Schnelle (1999) showed that vase-life can be prolonged by excising away the lowest 5 cm segment of the peduncle during their vase-life study, providing support for the above notion. Although previous studies (Shirakawa et al., 1964; Paull and Goo, 1985; Sankat and Mujaffar, 1994) point to impeded water uptake as a possible mechanism of loss of vase-life, cultivar differences have not been investigated in a range of cultivars with varying vase-lives to determine the relative importance of this in cutflower deterioration in anthurium. The objective of this study was to evaluate the water uptake behaviour in a range of anthurium cultivars with the objective of establishing a relationship between water uptake patterns and vase-life. 2. Material and methods 2.1. Location Vase-life experiments were conducted in two trials, Trial 1 (March–May, 2001) and Trial 2 (September–October, 2001) at the laboratories of the University of the West Indies, St. Augustine,
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Table 1 The 17 anthurium cultivars evaluated in the vase-life study and their stomata numbers on the abaxial surface in Trial 1 (March) and Trial 2 (September). Cultivars
Origin
Spathe colour
Acropolis Cuba Fantasia Pierrot Evergreen Local Pink Lydia Spirit Mirjam Success Tropical Honduras Midori Tequila Fla Range Terra Venus
The Netherlands The Netherlands The Netherlands The Netherlands The Netherlands Trinidad The Netherlands The Netherlands The Netherlands The Netherlands The Netherlands The Netherlands Hawaii The Netherlands The Netherlands The Netherlands The Netherlands
White White White White White with green lobes Pink Pink Pink Red Red Red Red and green Green Green Orange Bronze Coral
Sig. (P) Mean SEM LSD (0.05) CVwithin (%) Genotypic CV (%)
Trinidad. The cut-flowers were collected from a commercial farm, Kairi Blooms Ltd, in Arima, Trinidad, where anthurium is cultivated under uniform cultural and management conditions. 2.2. Cultivars and cultural conditions Cut-flowers used in the study were obtained from 3- to 4-yearold plants of 17 cultivars (Table 1). The cultivars were maintained at a spacing of 0.45 m 0.4 m on beds (23 m 1.2 m) made of pulverized coconut husk. The beds were fertilised with either triple super phosphate (Chemos GmBH, Regenstauf, Germany) or 12N11P-13K (Norsk Hydro Olje AB, NYBRO, Sweden), every month at a rate of approximately 0.45 kg per bed. Urea (National Agro, Port of Spain, Trinidad) and di-ammonium phosphate (Brenntag, Dominican Republic) were applied as necessary at a rate of 0.23 kg per bed. The pH of the bed was maintained at 5.6 through liming (Limestone, Trincarb, Trinidad). The plants were irrigated once daily for 15 min by overhead irrigation. 2.3. Harvesting and transport of cut-flowers Cut-flowers with no scratches, no deformities and straight peduncles were harvested at the 3/4 mature stage of the spadix. The cut-flowers were harvested with a sharp, sterile scalpel, packed in boxes containing wet shredded paper and transported to the University laboratory in an air-conditioned vehicle. 2.4. Experimentation In Trial 1, three cut-flowers from each of the 17 cultivars were placed separately in sterile, 250 ml measuring cylinders containing 210 ml of sterile distilled water, and maintained in a laboratory setting (11 h white fluorescent light; 23.8 8C; 73.5% RH). Before placing the cut-flowers into the cylinder the base of the peduncles were freshly cut under water at an angle of 458 using a sharp, sterile scalpel. The experiment was arranged in a completely randomised design with 3–8 replications per cultivar, depending on the availability of spathes of uniform maturity stage. The cylinders were covered with a cellophane wrap to prevent evaporation.
Abaxial stomata number (mm
2
)
Vase-life (days)
March
September
March
September
11.0 1.9 16.4 5.0 25.7 2.2 2.8 9.6 6.6 2.6 3.3 4.2 5.9 4.1 1.8 5.1 5.3
14.6 2.6 16.2 6.5 24.5 2.5 4.3 – 6.9 5.6 6.2 4.2 6.2 11.2 2.8 6.6 5.6
18 49 19 37 14 17 26 15 18 16 24 45 34 33 33 40 15
16 41 14.2 34.3 21 21 15 – 15 19 14 37.7 48.7 21.5 22 30 18
0.001 6.7 1.05 2.98 15.7 92.7
0.001 7.4 0.954 2.71 17.7 80.4
0.001 26.6 2.19 6.18 15.9 43.0
0.001 22.8 2.26 6.43 16.2 45.6
Cut-flowers were monitored for a period until loss of vase-life occurred. Vase-life was determined by whichever of the following occurred first: spadix browning/necrosis, spathe floppiness, spathe browning/necrosis, spathe discoloration, and loss of lustre/glossiness of spathe. Cylinders were topped to the original water level at the same time each day using a dispenser, and the amount of water required was noted as the water uptake for that day. Five-day mean water uptake rates (WUR) were calculated (per cut-flower basis) for each replicate of each of the 17 cultivars, for the study period. The experiment was continued until all the cultivars began to show the signs of deterioration. The water uptake curves based on 5-day mean WUR were plotted against time for each replicate plot of each cultivar and the time to inflection on the water loss curve (time to steady state water uptake) as well as the duration of steady state water uptake (SSW) and the rate of SSW were determined from the WUR curve. Abaxial stomata density was determined on three randomly selected spathes per cultivar. Four 1.5 0.5 cm pieces were cut from each spathe and placed in a clearing solution in a petri dish. The clearing solution was prepared by adding 15 g of NaOH pellets to 500 ml of water and 500 ml of 95% ethanol. The solution was replaced routinely as it became pigmented. Cleared sections were mounted on slides, stained with toluidine blue and warmed for 2 min on a slide warmer at 40 8C. Stomata density was enumerated for each section based on four views at 100 magnification using a light microscope (Euromex, the Netherlands). From this the mean number of stomata mm 2 on the abaxial spathe surface of each cultivar was calculated. The vase-life experiment described was repeated in Trial 2 using 16 of the 17 cultivars used in Trial 1 (except ‘Spirit’, due to unavailability of adequate cut-flowers) under the same conditions. Three replicates with three cut-flowers per replicate were evaluated for each cultivar. 2.5. Data analysis One-way ANOVA was conducted using NCSS (2001 version, Kaysville, Utah, USA) to determine the significance of cultivar
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differences for the 5-day WUR, time to SSW, duration of SSW, the SSW rate and vase-life. Pearson’s product moment correlation analysis (NCSS, 2001) was carried out to determine the correlation coefficients between the various water uptake parameters (5-day mean WUR, days to SSW, duration of SSW and SSW rate) and vase-life, stomata density and spathe colour. Step-wise multiple regression analysis (NCSS, 2001) was conducted to determine the proportion of variation in vase-life determined by the various water uptake parameters. 3. Results 3.1. Stomata density and vase-life There were significant (P < 0.001) cultivar differences in stomata density (mm 2) between cultivars, varying between 1.8 in cultivar ‘Fla Range’ and 25.7 in cultivar ‘Evergreen’ in Trial 1; and between 2.5 in ‘Local Pink’ and 24.5 in ‘Evergreen’ in Trial 2 (Table 1). Similarly there were significant (P < 0.001) cultivar differences in vase-life in both Trials 1 and 2 (Table 1), with vaselife varying between 14 (‘Evergreen’) and 49 days (‘Cuba’) among the cultivars tested in Trial 1, and between 14 (‘Tropical’ and ‘Fantasia’) and 49 days (‘Midori’) in Trial-2 (Table 2). The vase-life on average was 3 days longer in Trial 1 than in Trial 2. The correlation coefficient between vase-lives in Trials 1 and 2 was 0.72. 3.2. Average water uptake rate 3.2.1. Trial 1 There were significant cultivar differences (P < 0.001) between 5-day mean WUR from 5 to 45 days (Table 2). The mean WUR over all cultivars showed a steady decline up to 25 days after initiation (DAI) but showed an inflection (Fig. 1), which maintained WUR up to 40 DAI, but continued to decline rapidly thereafter. Table 3 shows that the time at which the inflection occurred (days to SSW),
Table 2 Five-day average water uptake rate (ml day Cultivar
Mirjam Venus Spirit Pierrot Fla Range Midori Terra Cuba Tropical Honduras Lydia Evergreen Success Tequila Acropolis Fantasia Local Pink a
Sig. level (P<) Mean LSD (0.05) CV within (%) Genotypic CV (%) Correlation to stomata no. Correlation to vase-life a
Significance.
) per cut-flower for 17 cultivars of anthurium over a 55-day period, post-harvesting, in a vase-life study (Trial 1).
10 1.33 1.40 1.50 1.65 0.95 2.40 2.26 2.19 1.14 1.27 0.93 2.79 1.13 1.11 1.01 1.51 2.26
0.001 1.58 0.47 0.20 272 0.40 0.11
3.2.2. Trial 2 There were significant cultivar differences (P 0.001) for 5-day mean WUR in Trial 2 (Table 4). Cultivars ‘Acropolis’, ‘Evergreen’, ‘Fantasia’, ‘Fla Range’, ‘Lydia’, ‘Mirjam’, ‘Success’, ‘Tropical’ and ‘Venus’ had WUR below the general mean of cultivars, while cultivar ‘Cuba’, ‘Midori’, ‘Pierrot’, ‘Tequila’ and ‘Terra’ had above average WUR. For the cultivar, ‘Honduras’ initial WUR was lower than the general mean, but by day 40 had values greater than the general mean. Again, cultivars with long vase-lives (>35 days) such as ‘Cuba’, ‘Pierrot’, ‘Midori’, ‘Honduras’ and ‘Terra’ took 35–50 days to experience a 65% decrease in WUR, whereas cultivars with short vase-lives (<20 days) took 10–30 days to experience a similar decrease (Table 4). By day 50, 62.5% of the cultivars ceased water uptake entirely. The time at which the inflection occurred on the water uptake curve, the duration of SSW and the SSW rate varied significantly (P < 0.001) among the 16 anthurium cultivars tested in Trial 2 and showed similar trends to Trial 1 (data not presented).
1
Average transpiration rate (ml day 5
the duration of SSW and the average SSW rates varied significantly (P < 0.001) among the 17 anthurium cultivars. As a result, the cultivars showing above average WUR varied with time. For instance, cultivars with long vase-lives (>35 days) such as ‘Cuba’, ‘Pierrot’, ‘Honduras’ and ‘Terra’ took 40–55 days to experience a 65% decrease in WUR, whereas cultivars with short vase-lives (<20 days) took 10–30 days to experience a similar decrease in WUR (Table 2). Table 3 shows that ‘Cuba’, ‘Honduras’, ‘Terra’, ‘Tequila’, ‘Pierrot’, ‘Fla Range’ and ‘Midori’ maintained a relatively higher WUR for a longer time (20–35 days). The mechanism that maintains a relatively high steady state was not triggered until some level of decline in WUR had occurred in the cultivars. There is some variation in the timing of this mechanism. Often the mechanism was triggered too late so that the cutflowers would have already started showing desiccation symptoms.
15 0.90 0.81 1.12 1.03 0.60 1.52 1.42 1.16 0.63 0.89 0.73 1.29 0.64 0.71 0.70 0.91 1.48
0.001 0.97 0.28 0.21 315 0.22 0.15
1
) at day 20
0.62 0.61 0.88 0.79 0.44 1.24 1.10 0.98 0.63 0.78 0.58 0.84 0.64 0.76 0.58 0.80 1.26 0.001 0.80 0.32 0.29 338 0.03 0.24
0.53 0.48 0.86 0.69 0.40 1.13 1.30 0.91 0.58 0.66 0.51 0.42 0.58 0.84 0.42 0.51 0.99 0.001 0.69 0.31 0.30 260 0.31 0.46
25 0.49 0.48 0.76 0.68 0.33 0.97 1.13 0.74 0.39 0.51 0.42 0.26 0.60 0.73 0.36 0.42 0.68 0.001 0.59 0.30 0.34 250 0.36 0.45
30
35 0.48 0.47 0.60 0.66 0.40 0.82 1.11 0.71 0.30 0.50 0.24 0.23 0.53 0.82 0.39 0.20 0.59
0.001 0.53 0.36 0.46 219 0.41 0.53
0.35 0.18 0.56 0.68 0.47 0.82 1.16 0.73 0.27 0.44 0.40 0.24 0.64 0.87 0.33 0.20 0.67 0.001 0.53 0.36 0.48 196 0.43 0.57
40
45 0.25 0.09 0.24 0.70 0.44 0.70 0.87 0.80 0.11 0.59 0.29 0.31 0.62 0.84 0.22 0.24 0.62
0.001 0.47 0.32 0.47 176 0.37 0.70
0.20 0.13 0.11 0.69 0.44 0.59 0.80 0.70 0.19 0.53 0.07 0.30 0.41 0.67 0.30 0.19 0.38 0.001 0.39 0.32 0.57 169 0.29 0.78
50
55
0.17 0.13 0.10 0.48 0.37 0.28 0.38 0.70 0.00 0.54 0.00 0.00 0.00 0.44 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.07 0.17 0.24 0.56 0.00 0.50 0.00 0.00 0.00 0.50 0.00 0.00 0.00
(NS) 0.21 – – 91 0.40 0.91
(NS) 0.12 – – 59 0.30 0.80
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Fig. 1. Mean 5-day water uptake (ml) over all anthurium cultivars (diamonds) and mean 5-day water uptake (ml) for individual cultivar (squares): (a) Cuba, (b) Honduras, (c) Fantasia and (d) Honduras evaluated in Trial 1.
3.3. Character correlation and regression analysis Correlation coefficients between vase-life and 5-day mean WUR during the period 5–55 DAI increased from 0.11 to 0.91 in Table 3 Days to steady state water uptake and duration (days), transpiration (ml) at steady state and vase-life of 17 anthurium cultivars evaluated in Trial 1. Cultivar
a
Mirjam Venus Spirit Pierrot Fla Range Midori Terra Cuba Tropical Honduras Lydia Evergreen Fantasia Local pink Acropolis Tequila Success
15 20 30 20 30 15 15 15 15 25 25 20 30 25 20 15 20
15 10 5 25 25 20 30 35 10 30 15 20 15 15 25 30 20
c Sig. (P) Mean SEM LSD (0.05) Genotypic CV (%)
0.001 20.9 1.28 3.63 27.1
0.001 20.3 1.99 5.63 41.3
a b c
Days to SSW
Duration of bSSW (days)
Rate of SSW (ml day 1) 0.53 0.48 0.58 0.7 0.47 0.97 1.1 0.8 0.63 0.55 0.42 0.29 0.2 0.62 0.33 0.84 0.59 0.001 0.59 0.045 0.13 39.2
Days to SSW—days to steady state water uptake in water uptake curve. SSW—steady state water uptake. Significance.
Trial 1 (Table 2; Fig. 2) and from 0.24 to 0.85 in Trial 2 (Table 4). The correlation coefficients between vase-life and average WUR were significant from day 30 to day 50 (r = 0.53–0.91; P < 0.05) in Trial 1 and between day 25 and day 50 (r = 0.57–0.85; P < 0.05,) in Trial 2. The results indicate that the ability of an anthurium cultivar to maintain WUR later in the life of the cut-flower was correlated to vase-life. Although not significant (P > 0.05), interestingly, correlation between average WUR and stomata number showed a negative trend between 20 and 55 days in Trial 1 (Table 2), and between 25 and 50 days in Trial 2 (Table 4). In Trial 1, correlation coefficients between vase-life and duration of SSW (r = 0.78; P 0.01) and vase-life and SSW rate (r = 0.60; P < 0.05) were significant, but not between vase-life and days to SSW (r = 0.27; P > 0.05) (Table 5). Days to SSW, SSW rate and duration of SSW explained 7%, 36% and 61% of the variation in vase-life, respectively. Step-wise multiple regression analysis showed that SSW rate and duration of SSW explained 71% of the variation in vase-life in Trial 1. In Trial 2, vase-life showed significant correlation with days to SSW (r = 0.59; P < 0.05), duration of SSW (r = 0.69; P < 0.01), and with SSW rate (r = 0.77; P < 0.001). Days to SSW, SSW rate, duration of SSW rate explained 35%, 59% and 48% of the variation in vase-life, respectively. Again step-wise multiple regression analysis showed that SSW rate and duration of SSW explained 73% of variation and all three attributes (days to SSW, SSW rate and duration of SSW) together explained 81% of the variation in vaselife. These results again showed that the ability of an anthurium cultivar to maintain water uptake rates later in the life of the cutflower was correlated to vase-life. Abaxial stomata density did not correlate significantly with average daily water uptake (Table 4), days to SSW, duration of SSW,
W. Elibox, P. Umaharan / Scientia Horticulturae 124 (2010) 102–108
106 Table 4 Five-day means for water uptake (ml day Cultivar
1
) per cut-flower for a 50-day period, post-harvest for 16 cultivars of anthurium in a vase-life study (Trial 2).
Average transpiration rate (ml day 5
10
15
1
) at day 20
25
30
35
40
Acropolis Cuba Evergreen Fantasia Fla Range Honduras Local Pink Lydia Midori Mirjam Pierrot Success Tequila Terra Tropical Venus
3.67 5.20 5.27 4.67 4.53 3.33 8.60 2.87 4.93 3.2 4.87 2.87 5.00 10.0 3.47 4.27
2.07 3.20 3.73 2.53 2.80 2.33 5.27 1.80 3.13 2.07 3.13 1.73 3.20 6.40 2.27 2.67
2.00 2.80 3.80 1.27 2.13 2.13 3.93 1.33 3.00 1.53 2.33 1.13 3.07 5.40 1.47 2.60
1.53 2.80 3.53 1.40 1.47 1.73 3.07 1.23 2.67 1.13 2.27 1.40 2.93 4.80 1.07 1.93
1.40 2.60 1.60 0.67 1.20 1.47 2.33 1.07 2.47 1.20 1.73 0.93 2.53 3.93 0.67 1.73
0.87 2.73 0.67 0.40 1.47 1.60 1.93 0.53 2.33 1.27 1.87 1.20 2.73 3.87 0.40 1.27
0.40 2.67 0.67 0.67 1.47 1.33 1.47 0.40 2.13 0.73 2.00 1.33 2.33 3.47 0.40 1.40
0.44 2.13 0.11 0.67 0.78 1.24 0.89 0.89 1.80 0.78 2.00 0.44 1.60 2.27 0.56 0.67
a
0.001 4.8 1.23 40.8 0.04 0.24
0.001 3.02 0.82 41.4 0.02 0.26
0.001 2.5 0.88 46.4 0.09 0.38
0.001 2.19 1.04 47.5 0.17 0.44
0.001 1.72 0.92 50.3 0.16 0.57
0.001 1.57 0.73 62.0 0.35 0.63
0.001 1.43 0.66 63.0 0.34 0.67
0.001 1.08 0.76 62.4 0.42 0.75
Sig. (P) Mean LSD (0.05) Genotypic CV (%) Correlation to stomata no. Correlation to vase-life a
45
50 0.00 2.20 0.00 0.00 0.00 1.07 0.00 0.00 1.43 0.00 1.07 0.00 1.80 0.83 0.00 0.00
0.001 0.53 0.87 145.0 0.22 0.79
0.00 2.20 0.00 0.00 0.00 0.93 0.00 0.00 1.53 0.00 1.07 0.00 1.27 0.67 0.00 0.00 0.001 0.48 0.75 148.3 0.25 0.85
Significance.
Table 5 Pearson’s correlation coefficients between water uptake parameters (days to SSW, duration of SSW and SSW rate) and vase-life, abaxial stomata density and 5-day mean water uptake over the period 5–50 days in Trials 1 and 2. Trial 1 Days to SST Vase-life Abaxial stomata density Days to SST Duration of SST Transpiration day 5 Transpiration day 10 Transpiration day 15 Transpiration day 20 Transpiration day 25 Transpiration day 30 Transpiration day 35 Transpiration day 40 Transpiration day 45 Transpiration day 50 Transpiration day 55 a
0.27 0.16 1.00 0.34 0.26 0.16 0.20 0.35 0.37 0.48 0.37 0.34 0.44 0.27 0.32
Trial 2 Duration of SST 0.78 0.18 0.34 1.00 0.15 0.07 0.14 0.27 0.27 0.47 0.53 0.76 0.85 0.76 0.75
SST Rate 0.60 0.53 0.60 0.40 0.33 0.45 0.57 0.87 0.90 0.93 0.89 0.76 0.74 0.57 0.51
Days to SST
Duration of SST
0.59 0.20 1.00 0.67 0.27 0.30 0.35 0.45 0.46 0.44 0.43 0.53 0.74 0.73 a –
0.69 0.25 0.67 1.00 0.04 0.03 0.09 0.18 0.33 0.39 0.43 0.50 0.85 0.86 –
SST Rate 0.77 0.07 0.79 0.46 0.58 0.60 0.59 0.69 0.78 0.82 0.82 0.87 0.79 0.75 –
In Trial 2, 5-day transpiration was monitored up to 50 days only.
SSW rate or vase-life (P > 0.05) in Trial 2, but was correlated to SSW rate alone in Trial 1 (Table 5). 4. Discussion The relatively long vase-life and the large cultivar variation in vase-life in anthurium have attracted considerable interest. There was more than a 3.5-fold variation (14–49 days) in vase-life among the anthurium cultivars tested. Cultivars ‘Cuba’, ‘Honduras’, ‘Pierrot’, ‘Terra’ and ‘Midori’ had consistently long vase-lives in both trials. In contrast, ‘Evergreen’, ‘Mirjam’, ‘Acropolis’ and ‘Venus’ had consistently short vase-lives. Cultivar differences in vase-life have also been reported in carnation (Wu et al., 1991), gerbera (Wernett et al., 1996) and roses (Ichimura et al., 2002). 4.1. Water stress and loss of vase-life Fig. 2. Correlation coefficients between average daily water uptake rates of cutflowers of 17 anthurium cultivars measured at 5-day intervals and vase-life (Trial 1).
Many researchers have shown that symptoms associated with the end of vase-life in anthurium are typical of water stress
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(Shirakawa et al., 1964; Paull, 1982), which is in agreement with this study. The end of vase-life was associated with wilting, loss of glossiness, darkening or bluing of the spathe, as has been observed in previous studies (Paull, 1982; Paull and Goo, 1985). Water stress is a function of the water content at harvest, and the rates of water uptake and water loss after harvest (Halevy and Mayak, 1981; Meman and Dabhi, 2006). Mujaffar and Sankat (2003) showed using one cultivar of anthurium that water stress symptoms appear when the balance between transpiration loss and water uptake exceed 1.5. Consequently, spadix removal (Paull and Goo, 1985) or waxing of anthurium cut-flowers (Paull and Goo, 1985; Mujaffar and Sankat, 2003), that aims to reduce transpiration rate (Mujaffar and Sankat, 2003), have been shown to improve vase-life in anthurium. Similar to the findings of a previous study (Elibox and Umaharan, 2008), this study showed that vase-life was not significantly correlated to abaxial stomatal density, which is usually a function of transpiration losses. Instead vase-life was strongly correlated to water uptake rate, which indicates that the latter may have a more important role in determining the water balance status of anthurium cultivars. That WUR may have an important role on the water status of anthurium cut-flowers is evident from a number of studies, Dole and Schnelle (1999) showed that vase-life can be prolonged by excising away the lowest 5 cm segment of the peduncle during their vase-life study, which maintains WUR for longer periods of time. Low temperature storage was also shown to prolong vase-life by retarding both vascular occlusion and transpiration rate (Mujaffar and Sankat, 2003), while pulsing with BA presumably retards vascular occlusion in extending vase-life (Paull and Goo, 1985). The progressively stronger correlation between vase-life and mean daily WUR during the 25–50 day period in Trials 1 and 2, indicate that cultivars that maintained above average WUR over the 50-day period had a longer vase-life. This suggests that cultivar differences in vase-life may be mediated though differences in their ability to maintain a high WUR, particularly during this period of the vase-life experiment. Cultivar differences in the ability to maintain high WUR was evident in the WUR-time curve as an inflection, resulting in the levelling off of water uptake rates. The study showed that cultivars which were able to achieve SSW earlier and maintain a high SSW for a longer duration were able to prolong their vase-life. In Trial 1, duration of SSW and SSW rate explained 71% of the variation in vase-life, while in Trial 2, days to SSW, duration of SSW and SSW rate together explained 81% of the variation in vase-life among cultivars. These results indicate a significant role for WUR in regulating the water status and ultimately vase-life in anthurium. 4.2. Vascular occlusion The mean WUR for all cultivars was initially high, but steadily decreased over time, consistent with observations by Paull and Goo (1985). This decline in WUR in cut-flowers in general is attributed to the decrease in hydraulic conductivity at the peduncle base due to vascular occlusion (de Witte and van Doorn, 1992; van Doorn et al., 1995). Vascular occlusion as a mechanism for water stress induced senescence in anthurium has been also suggested by Paull and Goo (1985). There was evidence from this study that the rate of decrease in WUR, resulting from vascular occlusion as shown by Paull and Goo (1985), varied with cultivars. Cultivars with a vase-life of over 35 days took 40–55 days in Trial 1 and 35–50 days in Trial 2, to experience a 65% decline in WUR. In contrast, cultivars with vaselives of less than 20 days took 10–30 days in both Trials 1 and 2 to experience a similar 65% reduction in WUR This suggests that the vascular occlusion process may have been slow and incomplete in the cultivars with longer vase-life. This is in agreement with the
107
findings of Salvi et al. (1997). In conclusion, the results suggest that water uptake rates are maintained, albeit at a lower rate, in some cultivars despite the vascular occlusion process (van Doorn et al., 1995; Paull and Goo, 1985), which allows these cultivars to maintain water status, and thereby extend their vase-life. Paull and Goo (1985) suggested that wound induced ethylene production possibly accounted for the vascular occlusion process, since other known factors, such as occlusion due to air-blockage (Teshigahara, 1982) or bacteria (Durkin and Put, 1995; Noordegraaf, 1999) could not be attributed to this process. 4.3. Mechanisms governing cultivar differences Noordegraaf (1999), van Doorn (1999) and Mujaffar and Sankat (2003) have showed that water uptake and loss by transpiration must be balanced, or otherwise, the cut-flowers will wilt and show symptoms of water shortage. The two stages of WUR that reflect vase-life of the anthurium cut-flower are: (i) Phase 1—phase of declining WUR rate (initial period of 0–20 days), which is a function of the rapidity and degree of vascular occlusion (days to SSW and SSW rate) and (ii) Phase 2—phase of steady state water uptake during the subsequent period (duration of SSW), may be function of other senescence factors associated with membrane integrity. The WUR curves showed various patterns (reflecting differences in days to SSW, SSW rate and SSW duration) among cultivars with long vaselives, indicating that the mechanism/s governing cultivar differences in vase-life may differ with cultivars. Elibox and Umaharan (2008) contended that at least part of the cultivar variation in vase-life in anthurium was attributed to abaxial stomata number and spathe colour. They argued that while abaxial stomatal number was related to transpiration losses, the effect of spathe colour may determine other senescence factors. The dominant pigments in white cultivars are flavones (Iwata et al., 1985), which have a strong and proven antioxidant capacity (Rice-Evans et al., 1997) and are excellent free radical scavengers. Furthermore, flavones may be involved in maintaining membrane integrity or they may have a role in protection from photo-inhibition (Gould et al., 1995; Gould et al., 2000; Dodd et al., 1998). It is proposed that a balance between factors affecting water uptake which is determined by the timing, extent and duration of vascular occlusion, and those that affect water loss (e.g. affecting stomatal regulation) may contribute to cut-flower senescence in anthurium. The study shows that water uptake parameters explain a large proportion of cultivar variation in vase-life, indicating that waterloss plays a prominent role in determining water status and thus vase-life of anthurium cutflowers. Understanding the mechanism of differences in uptake would provide opportunities for extending vase-life. Further studies are being conducted to determine the mechanisms. Acknowledgements This study was funded by the EUFORUM/CARIFORUM under the Caribbean Agricultural Technology Fund (CARTF) programme. We thank the management and staff of Kairi Blooms Farm for providing the facilities for the research. References Croat, T.B., 1988. Ecology and life forms of Araceae. Aroideana 11, 4–55. de Witte, Y., van Doorn, W.G., 1992. The mode of action of bacteria in the vascular occlusion of cut rose flowers. Acta Hort. 298, 155–170. Dodd, I.C., Critchley, C., Woodall, G.S., Stewart, G.R., 1998. Photoinhibition in differently coloured juvenile leaves of Syzygium species. J. Exp. Bot. 49, 1437–1445. Dole, J., Schnelle, M.A., 1999. The Care and Handling of Cut Flowers. Okla State Coop. Ext. Serv., F-6426.
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Durkin, D.J., Put, H.M.C., 1995. Scanning electron microscope observations of the cut surface of Rosa ‘Kardinal’ influenced by vase water composition. Acta Hort. 405, 97–100. Elibox, W., Umaharan, P., 2008. Morphophysiological characteristics associated with vase life of cut flowers of Anthurium. HortScience 43 (3), 825–831. Gould, K.S., Kuhn, D.N., Lee, D.W., Oberbauer, S.F., 1995. Why leaves are sometimes red. Nature 378, 241–242. Gould, K.S., Markham, K.R., Smith, R.H., Goris, J.J., 2000. Functional role of anthocyanins in the leaves of Quintinia serrata A. Cunn. J. Exp. Bot. 51 (347), 1107– 1115. Halevy, A.H., Mayak, S., 1981. Senescence and postharvest physiology of cut flowers: part 2. Hort. Rev. 3, 59–143. Ichimura, K., Kawabata, Y., Kishimoto, M., Goto, R., Yamada, K., 2002. Variation with the cultivar in the vase life of cut rose flowers. Bull. Natl. Inst. Flor. Sci. 2, 9–20. Iwata, R.Y., Tang, C.S., Kamemoto, H., 1985. Concentration of anthocyanins affecting spathe colour in anthuriums. J. Am. Soc. Hort. Sci. 110, 383–385. Kamemoto, H., Kuehnle, A.R., 1996. Breeding Anthuriums in Hawaii. University of Hawaii Press, Honolulu. Meman, M.A., Dabhi, K.M., 2006. Effect of different stalk lengths and certain chemical substances on vase life of gerbera (Gerbera jamesonii Hook.) cv. ‘Savana Red’ J. Appl. Hort. 8 (2), 147–150. Mujaffar, S., Sankat, C.K., 2003. Effect of waxing on the water balance and keeping qualities of cut anthuriums. Int. Agrophys. 17, 77–84. NCSS, 2001. Number Crunching Statistical System. NCSS, Kaysville, UT, USA. Noordegraaf, C.V., 1999. Problems of post harvest management in cut flowers. Acta Hort. 482, 53–58. Paull, R.E., 1982. Anthurium (Anthurium andraeanum Andre´) vaselife evaluation criteria. HortScience 17 (4), 606–607.
Paull, R.E., Chen, N.J., Deputy, J., 1985. Physiological changes associated with senescence of cut anthurium flowers. J. Am. Soc. Hort. Sci. 110, 156–162. Paull, R.E., Goo, T.T.C., 1985. Ethylene and water stress in the senescence of cut anthurium flowers. J. Am. Soc. Hort. Sci. 110, 84–88. Rice-Evans, C.A., Miller, N.J., Paganga, G., 1997. Antioxidant properties of phenolic compounds. Trends Plant Sci. 2, 152–159. Salvi, B.R., Valsalakumari, P.K., Rajeevan, P.K., Geetha, C.K., 1997. Effect of holding solutions on cut anthurium flowers. Hort. J. 10 (2), 65–72. Sankat, C.K., Mujaffar, S., 1994. Water balance in cut Anthurium flowers in storage and its effect on quality. Acta Hort. 368 (2), 723–732. Shirakawa, T., Edolph, R.D., Watson, D.P., 1964. N-6-Benzyladenine effects on chilling injury, respiration and keeping quality of Anthurium andraeanum. Proc. Am. Soc. Hort. Sci. 85, 642–646. Teshigahara, W., 1982. Ikebana, a New Illustrated Guide to Mastery. Kodansha International Ltd, Tokyo, Japan. van Doorn, W.G., de Witte, Y., Harkema, H., 1995. Effect of high numbers of exogenous bacteria on the water relations and longevity of cut carnation flowers. Postharv. Biol. Technol. 6, 111–119. van Doorn, W.G., 1999. Vascular occlusion in cut flowers. I. General principles and recent advances. Acta Hort. 482, 59–63. Watson, D.P., Shirakawa, T., 1967. Gross morphology related to shelf-life of Anthurium flowers. Hawaii Farm Sci 16, 1–3. Wernett, H.C., Wilfret, G.J., Sheehan, T.J., Marousky, F.J., Lyrene, P.M., Knauft, D.A., 1996. Postharvest longevity of cut-flower Gerbera. I. Response to selection for vase life of components. J. Amer. Soc. Hort. Sci. 121, 216–221. Wu, M.J., Van Doorn, W.G., Reid, M.S., 1991. Variation in the senescence of carnation (Dianthus caryophyllus L.) cultivars. I. Comparison of flower life, respiration and ethylene biosynthesis. Sci. Hort. 48, 99–107.