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Effect of pretreatment of stock plants of mango with cycocel, ethrel and morphactin on the rooting of cuttings and air layers
Scientia Horticulturae, 10 (1979) 363--368 Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
363
EFFECT OF PRETREATMENT OF STOCK PLANTS OF MANGO WITH CYCOCEL, ETHREL AND MORPHACTIN ON THE ROOTING OF CUTTINGS AND AIR LAYERS
M.K. SADHU
University College of Agriculture, Calcutta University, Calcutta 700019 (India) (First received 25 July 1 9 7 8 ; i n revised form 7 December 1978)
ABSTRACT Sadhu, M.K., 1979. Effect of pretreatment of stock plants of mango with cycocel, ethrel and morphactin on the rooting of cuttings and air layers. Scientia Hortic., 10: 363--368. Pretreatment of stock plants with cycocel or ethrel induced rooting on cuttings and air layers of mango (Mangifera indica L.), a difficult-to-root fruit plant which normally does not regenerate roots. Application of IBA to the cuttings and air layers made from pretreated shoots improved rooting, cycocel pretreatment being more effective than ethrel. Morphactin pretreatment inhibited rooting, fully counteracting the auxin-induced rooting.
INTRODUCTION
Propagation of mango (Mangifera indica L.) by cutting or air layering is difficult, because shoots of mature plants do not regenerate roots easily and sufficiently under normal conditions. However, auxins and preconditioningtreatments such as girdling and etiolation of shoots have been shown to induce rooting on mango cuttings and air layers (Guhathakurta and Dutta, 1941; Mukherjee et al., 1967; Sen et al., 1968). The suppression of vegetative growth of easy-to-root stock plants by various cultural manipulations, such as nutritional starvation (Sen and Basu, 1960; Basu and Ghosh, 1974), girdling of shoots (Stoltz and Hess, 1966) and spraying with growth-retarding chemicals (Pugliano, 1968; Punjabi et al., 1974), has been found to be associated with increased rooting. However, it is yet to be seen whether the conclusion drawn from such materials would hold true for difficult-to-root materials. The present study was therefore initiated in order to investigate the rooting-performance of mango, a difficult-to-root fruit plant, pretreated with 3 growth regulators, cycocel, ethrel or morphactin.
364 MATERIALS AND METHODS
The experiment was conducted on 10-year old mango trees (cultivar 'Langra') receiving uniform cultural treatments in the orchard of the Agri-Horticultural Society of India, Calcutta. Two trees of uniform growth and vigour were sprayed with each of the following growth-regulating chemicals: Cycocel (2-chloroethyltrimethylammonium chloride, 10000 mg 1-1); Ethrel (2-chloroethylphosphonic acid, 250 mg 1"1); Morphactin (chlorflurenol, 50 mg 1-1). The chemicals were applied in aqueous sprays with Tween-20 (0.1%) as wetting-agent to the point of run off. The control trees received an aqueous spray of Tween-20 (0.1%) only. The first spraying was done in the middle of June and was repeated twice at weekly intervals. Three days after the last spray, 2X 40 terminal shoots of uniform growth were used for making cuttings and air layers. For making cuttings, 40-cm long terminal shoots were collected from the stock plants. The bases of half of the cuttings were dipped in indol-3-yl-butyric acid, 2X 10 -2 M (IBA) in 90% ethanol for 30 s and planted in sterile sand for rooting in an intermittant-mist-propagation chamber. For making air layers, a 5-cm long ring of bark was removed from the base of a b o u t 40-cm long shoots, and IBA, 2X 10 -2 M in 90% ethanol was applied at the upper end of the ring with a camel-hair brush. The treated area was then covered with a thick layer of moist sphagnum moss and then wrapped in polyethylene to prevent desiccation. Data on the number of cuttings and air layers rooted, number of roots per cutting or air layer, and dry weight of roots per cutting or air layer, were recorded after 60 days. The criterion of synergism was adopted from Gorter (1969) using the formula (d+a)--{b+c); where a, b, c and d stand for the number of roots per cutting or air layer under control, IBA, non-auxin chemical and IBA-plus-non-auxin chemical, respectively. The level of significance of the synergistic effect was determined by using 2-way interaction tables and F test (Fisher, 1948). For chemical analysis, 4-cm long basal segments of the pretreated shoots were sampled on the day of making cuttings and air layers. Sugars were estimated by the copper reduction m e t h o d of Somogyi (1945) and acid hydrolysable polysaccharides by the same method after removing soluble sugars and hydrolysing the residue with 6 N HC1 on a boiling-water bath for 3 h. Total nitrogen was determined b y the microkjeldahl procedure of Pregl (1930). Soluble nitrogen was determined by the above method after precipitating the proteins from the extracts of fresh material with trichloroacetic acid. For extraction and chromatography of endogenous root-promoting and -inhibiting compounds, the m e t h o d described by Taylor and O d o m (1970) was followed with certain modifications. Twenty-five-gram samples were extracted for 24 h with 75 ml aliquots of absolute ethanol at --5°C in darkness. The extraction was repeated three times. The extracts were then combined,
365
filtered and evaporated to dryness under reduced pressure at a b o u t 35 ° C. The residue was taken up in 2 ml of chilled 80% ethanol and stored at 0 ° C for future use. Two-gram equivalent of fresh plant material was streaked on 25 cm X 2.5 cm strips of Whatman No.3 MM paper and ascending chromatographic separation was carried o u t using isopropanol:water (8:2 v/v) as solvent, until the solvent front had advanced 20 cm from the starting-line. The paper chromatograms then were dried at room temperature and cut transversely into 10 equal parts. Each section was placed in a separate small glass vial. The bioactive factors resolved on the chromatograms were tested for their root-promoting or -inhibiting activity using cuttings of mung bean (Phaseolus aureus, Roxb.) made from 7-day old seedlings (Hess, 1964). Chromatogram sections were eluated with 5 ml IAA (5X 10 -s M) in phosphate buffer containing 1% sucrose. Ten uniform cuttings were placed in each vial. The solution was taken up within 24 h and glass-distilled water was then added to the vials daily to maintain the original solution volume. Data on root number were recorded after 7 days. As measures of the net rooting-factor activity, units of promotion values were calculated from the histograms as the difference between the area of promotion and that of inhibition (Taylor and Odom, 1970). RESULTS AND DISCUSSION
Cycocel, ethrel and morphactin pretreatments inhibited shoot extension to 35.6, 28.0 and 6.5% of the control, respectively. Ethrel caused yellowing of leaves after the third spray. These leaves appeared non-functional and abscised within 7 days after making of cuttings and air layers. However, ethrel-pretreated cuttings and air layers sprouted early, producing y o u n g active leaves. Leaves on cuttings and air layers under cycocel were dark green in colour and remained intact for a long time. Morphactin-treated shoots produced small, dark green leaves. Pretreatment of stock plants with cycocel or ethrel improved rooting on cuttings and air layers in the presence of IBA (Table 1). The effect of cycocel was synergistic and that of ethrel was mostly additive. Although the application of morphactin brought a b o u t significant growth reduction in stock plants, the pretreatment did n o t show any beneficial effect on rooting. Morphactintreated shoots failed to initiate roots even in the presence of IBA. This is in contrast to the findings of Punjabi et al. (1974), who recorded synergistic increase in rooting of bean cuttings made from morphactin-pretreated stock plants. It was further noted that the r o o t systems produced on cuttings and air layers of pretreated shoots in the presence of IBA were more branched, vigorous and less brittle than those produced on cuttings or air layers treated with IBA only. The dry weights of such roots were also much higher than under IBA alone. Apparently, this improvement in the quality of roots was instrumental in the better survival of cuttings and air layers (Table 1).
Morphactin
Ethrel
Air layers Control Cycocel
0
30
--
40
0
--
0
--
0
---
10
0
10
Ethrel
Morphactin
0 0
--
2.8-+0.23
--
0.4_+ 0 . 0 2
--
0.6-+0.03
---
--
81.6-+ 2 . 1 3
--
25.8+ 1.20
--
36.2_+3.42
---
Mean dry wt. of roots/cutt i n g o r air layer (mg)
0
60
90
40
0
30
10 50
Percentage rooting
Mean no. of roots/cutting o r air l a y e r
Percentage rooting
Percentage survival
IBA
Control
Cuttings Control Cycocel
Pretreatment
--
70
80
30
--
40
0 60
Percentage survival
--
(+0.4)
5.1-+ 0 . 3 2
(+5.0**)
6.9-+ 0 . 3 4
2.3-+ 0 . 1 9
--
(+0.3)
1.2_+0.06 5.8_+ 0 . 3 6 (+4.6**) 2.1-+0.15
Mean no. of roots/cutting o r air l a y e r
--
472.8-+ 2 1 . 6 1
745.5+31.65
260.6-+ 2 0 . 1 2
--
230.7+_24.50
121.3-+ 5 . 7 2 590.6+ 33.25
Mean dry wt. of roots/cutr i n g o r air layer (mg)
R o o t i n g - p e r f o r m a n c e o f m a n g o h a r d w o o d s t e m c u t t i n g s a n d air l a y e r s in r e s p o n s e t o p r e t r e a t m e n t s o f s t o c k p l a n t s . V a l u e s in p a r e n t h e s e s d e n o t e i n c r e a s e ( + ) in r o o t n u m b e r d u e t o s y n e r g i s m b e t w e e n t h e a u x i n ( I B A ) a n d t h e r e s p e c t i v e n o n - a u x i n c h e m i c a l ; ** = signif i c a n t at P = 0 . 0 1
TABLE 1
O$ O~
367
Table 2 shows increased accumulation of carbohydrate reserves in the rootforming region of shoots of cycocel- and ethrel-pretreated plants. Protein and total N content of shoots were higher in such plants. TABLE 2 Carbohydrate and nitrogen content (percent dry weight) of mango shoots as influenced by pretreatments. NS = Not significant Contents
Pretreatments Control
Total sugar Reserve polysaccharides Total carbohydrates Soluble nitrogen Protein nitrogen Total nitrogen C/N ratio
Cycocel
LSD Ethrel
Morphactin
(P=0.01)
6.9
8.3
8.1
7.4
0.9
12.0
13.9
13.5
12.8
1.2
18.9 0.40 0.24 0.64 29.53
22.2 0.33 0.30 0.72 30.83
21.6 0.31 0.40 0.71 30.42
20.2 0.36 0.34 0.70 28.85
1.5 NS 0.10 0.06 NS
Endogenous rooting-factors were detected in shoots from all treatments including control. Figure 1 shows that the highest content was present in cycoceltreated shoots, followed by ethrel. Morphactin showed the least accumulation. These rooting-factors were located at Rf zones 0.3--0.5, 0.7 and 0.9--1.0. With straight growth bioassay, however, these areas showed inhibition of coleoptile growth. The endogenous concentrations of plant-growth inhibitors increase during the period of growth suppression (Kefeli and Kadyrov, 1971). The involvement of abscisic acid and phenols in the process of regeneration has been reported by Gorter, 1969; Basu et al., 1969; Chin et al., 1969; Sadhu et al., 1972. However, the exact role of these substances in synergism is not known.
c I00, o
E .o
80 G0
~40 ~
20
nl
r-l CONTROL I~JcYCOCEL nlETHREL ~HORPHACTIN
Fig. 1. Accumulation of rooting-factors in mango shoots as influenced by certain pretreatments of stock plants.
368 ACKNOWLEDGEMENTS T h a n k s are d u e t o the Secretary, Agri-Horticultural S o c i e t y o f India, Calcutta, for p r o v i d i n g o r c h a r d facilities, and t o Dr. R.N. Basu f o r e n c o u r a g e m e n t and a gift sample o f m o r p h a c t i n .
REFERENCES Basu, R.N. and Ghosh, S.K., 1974. Effect of nitrogen nutrition of stock plants of Justicia gendarussa L. on the rooting of cuttings. J. Hortic. Sci., 49: 245--252. Basu, R.N., Bose, T.K., Roy, B.N. and Mukhopadhyay, A., 1969. Auxin synergists in rooting of cuttings. Physiol. Plant., 22: 649--652. Chin, Ting-yun, Meyer, M.M., Jr. and Beevers, L., 1969. Abscisic acid-stimulated rooting of stem cuttings. Planta, 88: 192--196. Fisher, R.A., 1948. Statistical methods for research workers. Oliver and Boyd, Edinburgh. Gorter, C.J., 1969. Auxin synergists in the rooting of cuttings. Physiol. Plant., 22: 497-502. Guhathakurta, A. and Dutta, B.K., 1941. Vegetative propagation of mango from gootes (marcotte) and cuttings by treatment with high concentration of auxin. Cur.. Sci., 10: 297. Hess, C.E., 1964. Naturally occurring substances which stimulate root initiation. In: J.P. Nitsch (Editor), Regulateurs Naturels de la Croissance Vegetale. C.N.R.S., Paris, pp. 517--527. Kefeli, V.I. and Kadyrov, C.S., 1971. Natural growth inhibitors, their chemical and physiological properties. Annu. Rev. Plant Physiol., 22: 185--196. Mukherjee, S.K., Majumdar, P.K., Bid, N.N. and Goswami, A.M., 1967. Standardization of root stocks of mango (Mangifera indica L.). II. Studies on the effects of source, invigoration and etiolation on the rooting of mango cuttings. J. Hortic. Sci., 42: 83--87. Pregl, F., 1930. Quantitative organic microanalysis. (Eng. Trans. by E. Fyleman, 2nd edn.), Churchill, London. Pugliano, G., 1968. The rooting of simple cuttings of clones of Vitis berlandieri (Planchan) and its hybrid watered with 2-chloroethyltrimethyl ammonium chloride (CCC). Ann. Fac. Sci. Agar. Napoli, 3: 252--263. Punjabi, B., Paria, N.C. and Basu, R.N., 1974. Opposing effects of morphactin on the rooting of cuttings in the presence or absence of auxin. J. Hortic. Sci., 49: 252--256. Sadhu, M.K., Naskar, B. and Basu, R.N., 1972. Auxin synergists in the rooting of air layers of tropical fruit trees. Indian Agric., 16: 251--257. Sen, P.K. and Basu, R.N., 1960. Effect of growth substances on root formation in cuttings of Justicia gendarussa L. as influenced by varying levels of nitrogen nutrition of stock plants. Indian J. Plant Physiol., 3: 72--83. Sen, P.K., Basu, R.N., Bose, T.K. and Roychoudhury, N., 1968. Rooting of mango cuttings under mist. Curr. Sci., 37 : 144--146. Somogyi, M., 1945. A new reagent for determination of sugars. J. Biol. Chem., 160: 61--68. Stoltz, L.P. and Hess, C.E., 1966. Effect of girdling upon root initiation: carbohydrate and amino acids. Proc. Am. Soc. Hortic. Sci., 89: 734--743. Taylor, G.G. and Odom, R.E., 1970. Some biochemical compounds associated with rooting of Carya illinoensis stem cuttings. J. Am. Soc. Hortic. Sci., 95: 146--151.
363
EFFECT OF PRETREATMENT OF STOCK PLANTS OF MANGO WITH CYCOCEL, ETHREL AND MORPHACTIN ON THE ROOTING OF CUTTINGS AND AIR LAYERS
M.K. SADHU
University College of Agriculture, Calcutta University, Calcutta 700019 (India) (First received 25 July 1 9 7 8 ; i n revised form 7 December 1978)
ABSTRACT Sadhu, M.K., 1979. Effect of pretreatment of stock plants of mango with cycocel, ethrel and morphactin on the rooting of cuttings and air layers. Scientia Hortic., 10: 363--368. Pretreatment of stock plants with cycocel or ethrel induced rooting on cuttings and air layers of mango (Mangifera indica L.), a difficult-to-root fruit plant which normally does not regenerate roots. Application of IBA to the cuttings and air layers made from pretreated shoots improved rooting, cycocel pretreatment being more effective than ethrel. Morphactin pretreatment inhibited rooting, fully counteracting the auxin-induced rooting.
INTRODUCTION
Propagation of mango (Mangifera indica L.) by cutting or air layering is difficult, because shoots of mature plants do not regenerate roots easily and sufficiently under normal conditions. However, auxins and preconditioningtreatments such as girdling and etiolation of shoots have been shown to induce rooting on mango cuttings and air layers (Guhathakurta and Dutta, 1941; Mukherjee et al., 1967; Sen et al., 1968). The suppression of vegetative growth of easy-to-root stock plants by various cultural manipulations, such as nutritional starvation (Sen and Basu, 1960; Basu and Ghosh, 1974), girdling of shoots (Stoltz and Hess, 1966) and spraying with growth-retarding chemicals (Pugliano, 1968; Punjabi et al., 1974), has been found to be associated with increased rooting. However, it is yet to be seen whether the conclusion drawn from such materials would hold true for difficult-to-root materials. The present study was therefore initiated in order to investigate the rooting-performance of mango, a difficult-to-root fruit plant, pretreated with 3 growth regulators, cycocel, ethrel or morphactin.
364 MATERIALS AND METHODS
The experiment was conducted on 10-year old mango trees (cultivar 'Langra') receiving uniform cultural treatments in the orchard of the Agri-Horticultural Society of India, Calcutta. Two trees of uniform growth and vigour were sprayed with each of the following growth-regulating chemicals: Cycocel (2-chloroethyltrimethylammonium chloride, 10000 mg 1-1); Ethrel (2-chloroethylphosphonic acid, 250 mg 1"1); Morphactin (chlorflurenol, 50 mg 1-1). The chemicals were applied in aqueous sprays with Tween-20 (0.1%) as wetting-agent to the point of run off. The control trees received an aqueous spray of Tween-20 (0.1%) only. The first spraying was done in the middle of June and was repeated twice at weekly intervals. Three days after the last spray, 2X 40 terminal shoots of uniform growth were used for making cuttings and air layers. For making cuttings, 40-cm long terminal shoots were collected from the stock plants. The bases of half of the cuttings were dipped in indol-3-yl-butyric acid, 2X 10 -2 M (IBA) in 90% ethanol for 30 s and planted in sterile sand for rooting in an intermittant-mist-propagation chamber. For making air layers, a 5-cm long ring of bark was removed from the base of a b o u t 40-cm long shoots, and IBA, 2X 10 -2 M in 90% ethanol was applied at the upper end of the ring with a camel-hair brush. The treated area was then covered with a thick layer of moist sphagnum moss and then wrapped in polyethylene to prevent desiccation. Data on the number of cuttings and air layers rooted, number of roots per cutting or air layer, and dry weight of roots per cutting or air layer, were recorded after 60 days. The criterion of synergism was adopted from Gorter (1969) using the formula (d+a)--{b+c); where a, b, c and d stand for the number of roots per cutting or air layer under control, IBA, non-auxin chemical and IBA-plus-non-auxin chemical, respectively. The level of significance of the synergistic effect was determined by using 2-way interaction tables and F test (Fisher, 1948). For chemical analysis, 4-cm long basal segments of the pretreated shoots were sampled on the day of making cuttings and air layers. Sugars were estimated by the copper reduction m e t h o d of Somogyi (1945) and acid hydrolysable polysaccharides by the same method after removing soluble sugars and hydrolysing the residue with 6 N HC1 on a boiling-water bath for 3 h. Total nitrogen was determined b y the microkjeldahl procedure of Pregl (1930). Soluble nitrogen was determined by the above method after precipitating the proteins from the extracts of fresh material with trichloroacetic acid. For extraction and chromatography of endogenous root-promoting and -inhibiting compounds, the m e t h o d described by Taylor and O d o m (1970) was followed with certain modifications. Twenty-five-gram samples were extracted for 24 h with 75 ml aliquots of absolute ethanol at --5°C in darkness. The extraction was repeated three times. The extracts were then combined,
365
filtered and evaporated to dryness under reduced pressure at a b o u t 35 ° C. The residue was taken up in 2 ml of chilled 80% ethanol and stored at 0 ° C for future use. Two-gram equivalent of fresh plant material was streaked on 25 cm X 2.5 cm strips of Whatman No.3 MM paper and ascending chromatographic separation was carried o u t using isopropanol:water (8:2 v/v) as solvent, until the solvent front had advanced 20 cm from the starting-line. The paper chromatograms then were dried at room temperature and cut transversely into 10 equal parts. Each section was placed in a separate small glass vial. The bioactive factors resolved on the chromatograms were tested for their root-promoting or -inhibiting activity using cuttings of mung bean (Phaseolus aureus, Roxb.) made from 7-day old seedlings (Hess, 1964). Chromatogram sections were eluated with 5 ml IAA (5X 10 -s M) in phosphate buffer containing 1% sucrose. Ten uniform cuttings were placed in each vial. The solution was taken up within 24 h and glass-distilled water was then added to the vials daily to maintain the original solution volume. Data on root number were recorded after 7 days. As measures of the net rooting-factor activity, units of promotion values were calculated from the histograms as the difference between the area of promotion and that of inhibition (Taylor and Odom, 1970). RESULTS AND DISCUSSION
Cycocel, ethrel and morphactin pretreatments inhibited shoot extension to 35.6, 28.0 and 6.5% of the control, respectively. Ethrel caused yellowing of leaves after the third spray. These leaves appeared non-functional and abscised within 7 days after making of cuttings and air layers. However, ethrel-pretreated cuttings and air layers sprouted early, producing y o u n g active leaves. Leaves on cuttings and air layers under cycocel were dark green in colour and remained intact for a long time. Morphactin-treated shoots produced small, dark green leaves. Pretreatment of stock plants with cycocel or ethrel improved rooting on cuttings and air layers in the presence of IBA (Table 1). The effect of cycocel was synergistic and that of ethrel was mostly additive. Although the application of morphactin brought a b o u t significant growth reduction in stock plants, the pretreatment did n o t show any beneficial effect on rooting. Morphactintreated shoots failed to initiate roots even in the presence of IBA. This is in contrast to the findings of Punjabi et al. (1974), who recorded synergistic increase in rooting of bean cuttings made from morphactin-pretreated stock plants. It was further noted that the r o o t systems produced on cuttings and air layers of pretreated shoots in the presence of IBA were more branched, vigorous and less brittle than those produced on cuttings or air layers treated with IBA only. The dry weights of such roots were also much higher than under IBA alone. Apparently, this improvement in the quality of roots was instrumental in the better survival of cuttings and air layers (Table 1).
Morphactin
Ethrel
Air layers Control Cycocel
0
30
--
40
0
--
0
--
0
---
10
0
10
Ethrel
Morphactin
0 0
--
2.8-+0.23
--
0.4_+ 0 . 0 2
--
0.6-+0.03
---
--
81.6-+ 2 . 1 3
--
25.8+ 1.20
--
36.2_+3.42
---
Mean dry wt. of roots/cutt i n g o r air layer (mg)
0
60
90
40
0
30
10 50
Percentage rooting
Mean no. of roots/cutting o r air l a y e r
Percentage rooting
Percentage survival
IBA
Control
Cuttings Control Cycocel
Pretreatment
--
70
80
30
--
40
0 60
Percentage survival
--
(+0.4)
5.1-+ 0 . 3 2
(+5.0**)
6.9-+ 0 . 3 4
2.3-+ 0 . 1 9
--
(+0.3)
1.2_+0.06 5.8_+ 0 . 3 6 (+4.6**) 2.1-+0.15
Mean no. of roots/cutting o r air l a y e r
--
472.8-+ 2 1 . 6 1
745.5+31.65
260.6-+ 2 0 . 1 2
--
230.7+_24.50
121.3-+ 5 . 7 2 590.6+ 33.25
Mean dry wt. of roots/cutr i n g o r air layer (mg)
R o o t i n g - p e r f o r m a n c e o f m a n g o h a r d w o o d s t e m c u t t i n g s a n d air l a y e r s in r e s p o n s e t o p r e t r e a t m e n t s o f s t o c k p l a n t s . V a l u e s in p a r e n t h e s e s d e n o t e i n c r e a s e ( + ) in r o o t n u m b e r d u e t o s y n e r g i s m b e t w e e n t h e a u x i n ( I B A ) a n d t h e r e s p e c t i v e n o n - a u x i n c h e m i c a l ; ** = signif i c a n t at P = 0 . 0 1
TABLE 1
O$ O~
367
Table 2 shows increased accumulation of carbohydrate reserves in the rootforming region of shoots of cycocel- and ethrel-pretreated plants. Protein and total N content of shoots were higher in such plants. TABLE 2 Carbohydrate and nitrogen content (percent dry weight) of mango shoots as influenced by pretreatments. NS = Not significant Contents
Pretreatments Control
Total sugar Reserve polysaccharides Total carbohydrates Soluble nitrogen Protein nitrogen Total nitrogen C/N ratio
Cycocel
LSD Ethrel
Morphactin
(P=0.01)
6.9
8.3
8.1
7.4
0.9
12.0
13.9
13.5
12.8
1.2
18.9 0.40 0.24 0.64 29.53
22.2 0.33 0.30 0.72 30.83
21.6 0.31 0.40 0.71 30.42
20.2 0.36 0.34 0.70 28.85
1.5 NS 0.10 0.06 NS
Endogenous rooting-factors were detected in shoots from all treatments including control. Figure 1 shows that the highest content was present in cycoceltreated shoots, followed by ethrel. Morphactin showed the least accumulation. These rooting-factors were located at Rf zones 0.3--0.5, 0.7 and 0.9--1.0. With straight growth bioassay, however, these areas showed inhibition of coleoptile growth. The endogenous concentrations of plant-growth inhibitors increase during the period of growth suppression (Kefeli and Kadyrov, 1971). The involvement of abscisic acid and phenols in the process of regeneration has been reported by Gorter, 1969; Basu et al., 1969; Chin et al., 1969; Sadhu et al., 1972. However, the exact role of these substances in synergism is not known.
c I00, o
E .o
80 G0
~40 ~
20
nl
r-l CONTROL I~JcYCOCEL nlETHREL ~HORPHACTIN
Fig. 1. Accumulation of rooting-factors in mango shoots as influenced by certain pretreatments of stock plants.
368 ACKNOWLEDGEMENTS T h a n k s are d u e t o the Secretary, Agri-Horticultural S o c i e t y o f India, Calcutta, for p r o v i d i n g o r c h a r d facilities, and t o Dr. R.N. Basu f o r e n c o u r a g e m e n t and a gift sample o f m o r p h a c t i n .
REFERENCES Basu, R.N. and Ghosh, S.K., 1974. Effect of nitrogen nutrition of stock plants of Justicia gendarussa L. on the rooting of cuttings. J. Hortic. Sci., 49: 245--252. Basu, R.N., Bose, T.K., Roy, B.N. and Mukhopadhyay, A., 1969. Auxin synergists in rooting of cuttings. Physiol. Plant., 22: 649--652. Chin, Ting-yun, Meyer, M.M., Jr. and Beevers, L., 1969. Abscisic acid-stimulated rooting of stem cuttings. Planta, 88: 192--196. Fisher, R.A., 1948. Statistical methods for research workers. Oliver and Boyd, Edinburgh. Gorter, C.J., 1969. Auxin synergists in the rooting of cuttings. Physiol. Plant., 22: 497-502. Guhathakurta, A. and Dutta, B.K., 1941. Vegetative propagation of mango from gootes (marcotte) and cuttings by treatment with high concentration of auxin. Cur.. Sci., 10: 297. Hess, C.E., 1964. Naturally occurring substances which stimulate root initiation. In: J.P. Nitsch (Editor), Regulateurs Naturels de la Croissance Vegetale. C.N.R.S., Paris, pp. 517--527. Kefeli, V.I. and Kadyrov, C.S., 1971. Natural growth inhibitors, their chemical and physiological properties. Annu. Rev. Plant Physiol., 22: 185--196. Mukherjee, S.K., Majumdar, P.K., Bid, N.N. and Goswami, A.M., 1967. Standardization of root stocks of mango (Mangifera indica L.). II. Studies on the effects of source, invigoration and etiolation on the rooting of mango cuttings. J. Hortic. Sci., 42: 83--87. Pregl, F., 1930. Quantitative organic microanalysis. (Eng. Trans. by E. Fyleman, 2nd edn.), Churchill, London. Pugliano, G., 1968. The rooting of simple cuttings of clones of Vitis berlandieri (Planchan) and its hybrid watered with 2-chloroethyltrimethyl ammonium chloride (CCC). Ann. Fac. Sci. Agar. Napoli, 3: 252--263. Punjabi, B., Paria, N.C. and Basu, R.N., 1974. Opposing effects of morphactin on the rooting of cuttings in the presence or absence of auxin. J. Hortic. Sci., 49: 252--256. Sadhu, M.K., Naskar, B. and Basu, R.N., 1972. Auxin synergists in the rooting of air layers of tropical fruit trees. Indian Agric., 16: 251--257. Sen, P.K. and Basu, R.N., 1960. Effect of growth substances on root formation in cuttings of Justicia gendarussa L. as influenced by varying levels of nitrogen nutrition of stock plants. Indian J. Plant Physiol., 3: 72--83. Sen, P.K., Basu, R.N., Bose, T.K. and Roychoudhury, N., 1968. Rooting of mango cuttings under mist. Curr. Sci., 37 : 144--146. Somogyi, M., 1945. A new reagent for determination of sugars. J. Biol. Chem., 160: 61--68. Stoltz, L.P. and Hess, C.E., 1966. Effect of girdling upon root initiation: carbohydrate and amino acids. Proc. Am. Soc. Hortic. Sci., 89: 734--743. Taylor, G.G. and Odom, R.E., 1970. Some biochemical compounds associated with rooting of Carya illinoensis stem cuttings. J. Am. Soc. Hortic. Sci., 95: 146--151.