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The effects of various night-temperature regimes on the vegetative growth and fruit production of tomato plants
Scientia Horticulturae, 27 (1985) 9--13
9
Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
THE EFFECTS OF VARIOUS NIGHT-TEMPERATURE REGIMES ON THE VEGETATIVE GROWTH AND FRUIT PRODUCTION OF TOMATO PLANTS
E. KHAYAT, D. RAVAD and N. ZIESLIN
Department of Ornamental Horticulture, The Hebrew University of Jerusalem, Rehovot 76100 (Israel) (Accepted for publication 8 May 1985)
ABSTRACT Khayat, E., Ravad, D. and Zieslin, N., 1985. The effects of various night-temperature regimes on the vegetative growth and fruit production of tomato plants. Scientia Hortic., 27: 9--13. The fruit production of tomato cultivar 'Moneymaker' was not reduced by interruption of the optimal night-temperature regime by short intervals of lower temperature. The same treatment increased the yield of 'Cherry' by 82% in the comparison with a constant night temperature of 18°C. The increase in yield of this cultivar was due to a larger number of fruits per plant. Interruption of the optimal night-temperature regime by a pulsing temperature regime (PTR) may be introduced as a method in the cultivation of greenhouse tomato plants for energy saving and for promotion of fruit-set in certain tomato cultivars. Keywords: energy saving; temperature; tomato. Abbreviations: HTR = high-temperature regime; LTR = low-temperature regime; PTR = pulsing temperature regime.
INTRODUCTION
Partial replacement of optimal temperature conditions by periods of suboptimal temperature is used for conserving energy in the cultivation of greenhouse crops (Gent et al., 1979). The response to this heating technique varied according to the plant species examined. A small effect was exhibited on the growth and fruit or flower production of tomatoes and lilies when a portion of the optimal night-temperature period was replaced by a lower temperature, a method known as "split night-temperature regime" (Gent et al., 1979). Flower production of roses was reduced and flowering was postponed by using this technique (Hanan, 1979; Shanks and Osnos, 1980). However, interruption of the night-temperature regime by shorter, but repetitive, intervals of sub-optimal temperature-pulsing temperature regime 0304-4238/85/$03.30
© 1985 Elsevier Science Publishers B.V.
10
(PTR) did not cause a reduction in the number of flowers of certain rose cultivars, while one of the cultivars examined even responded with an increase in the number of flowers formed (Zieslin et al., 1985a). Positive responses were also observed in preliminary experiments with some other plant species when PTR was used (Zieslin et al., 1985b). MATERIALS AND METHODS
Seeds of 2 tomato cultivars, 'Moneymaker' and 'Cherry 35070E Danmark' (Cherry 688, FA Israel) were sown on 28 December 1983. A night temperature of 18°C was maintained during the germination period. Following germination, seedlings with one true leaf were planted in 5-1 containers with a growth medium which contained peat-moss and volcanic scoria (1:1 v/v). The plants were irrigated once or twice daily with a nutrient solution containing microelements. The plants were transferred on 6 January 1984 to 3 greenhouse compartments with 3 different night-temperature regimes: (1) HTR, minimum of 18 + 1°C constantly (high-temperature regime), (2) LTR, minimum of 12 + I°C constantly (low-temperature regime), (3) PTR, 18 and 12°C repeated every 2 h (pulsing-temperature regime). The minimal and maximal day temperatures of 18 and 30°C, respectively, were maintained in all the 3 compartments. The data were collected individually from each plant; 12 plants per treatment. The statistical analysis was made by multiple range test, and figures accompanied by different letters are significantly different at P = 0.05. RESULTS
The number of leaves developed before the formation of the first inflorescence was reduced by LTR and by PTR in b o t h cultivars examined (Table I). Stem elongation of 'Cherry' was not affected by the different temperature treatments, and the observed differences in the final lengths were
TABLE I The influences o f n i g h t - t e m p e r a t u r e regimes o n the n u m b e r o f leaves p r e c e d i n g the form a t i o n o f t h e first i n f l o r e s c e n c e in 2 t o m a t o cultivars Night-temperature regime
'Cherry'
'Moneymaker'
C o n s t a n t at 18°C = HTR C o n s t a n t at 12°C = L T R 18/12 °C = PTR
10.7 a 8.4 b 8.6 b
8.0 a 7.2 b 7.3 b
11
insignificant (Fig. 1A). However, the stem length of 'Moneymaker' plants was significantly reduced by the LTR and to a greater extent by the PTR (Fig. 1B). In both cultivars the final number of leaves was reduced by LTR, but was n o t affected by PTR (Table II). The number of flower trusses of 'Moneymaker' was reduced by the LTR, while PTR had no effect on this parameter (Table III). A different response was shown by 'Cherry'. While the LTR did not affect the number o f flower trusses, an increase of 10% in this parameter was obtained under the PTR (Table III). The total fruit yield and some other parameters of tomato fruit production are summarized in Table IV. The data show the differences in the responses of the two cultivars to changes in the night-temperature regimes. Although the yield of 'Cherry' was not affected by the LTR, the yield of 'Moneymaker' was reduced by 23% in comparison with the HTR. The fruit I
,6° I
i
i
i
1
I
I
®'MON*EYM,K;R
CHERRY
'
' .
120
g :~LTR
z~
J L
7
L 14
I 24
I 30
1
37
l I I l I 48 56 7 14 24 DAYS FROM TRANSPLANTING
I
30
1
37
1
48
I
56
Fig. 1. The i n f l u e n c e o f n i g h t - t e m p e r a t u r e regimes o n the length o f t h e main s h o o t o f t o m a t o p l a n t s o f t w o cultivars: A, ' C h e r r y ' ; B, ' M o n e y m a k e r ' . o, 18°C = H T R ; *, 12°C = L T R ; *, 18/12°C = PTR. T A B L E II The i n f l u e n c e o f n i g h t - t e m p e r a t u r e regimes o n t h e n u m b e r o f leaves d e v e l o p e d o n the main s t e m o f t o m a t o plants. The figures are the average n u m b e r o f leaves p e r plant Night-temperature regime
'Cherry'
'Moneymaker'
C o n s t a n t at 18°C = H T R C o n s t a n t at 12°C = L T R 18/12 °C = P T R
30.0 a 27.5 b 29.5 a
28.7 a 26.8 b 28.0 a
12 T A B L E III T h e influence o f n i g h t - t e m p e r a t u r e regimes o n the n u m b e r o f f l o w e r trusses o n t o m a t o plants. T h e figures are average n u m b e r s o f f l o w e r trusses p e r p l a n t Night-temperature regime
'Cherry'
'Moneymaker'
C o n s t a n t at 18°C = H T R C o n s t a n t at 12°C = L T R 1 8 / 1 2 °C = P T R
6.6 b 6.0 b 7.3 a
6.8 a 5.6 b 6.6 a
T A B L E IV T h e e f f e c t o f t h e n i g h t - t e m p e r a t u r e regime o n various p a r a m e t e r s o f fruit yields o f tomato plants 'Cherry' and 'Moneymaker' Temperature regime
C o n s t a n t 18°C -- H T R C o n s t a n t 12°C = LTR 1 8 / 1 2 °C = P T R
Yield p e r p l a n t (g)
N u m b e r o f fruits per p l a n t
Av. fruit w e i g h t (g)
'Cherry'
'Moneymaker'
'Cherry'
'Moneymaker'
'Cherry'
'Moneymaker'
823 b
2027 a
49.0 b
25.1 b
16.7 a
80.6 a
909 b 1503a
1571 b 2267a
56.6 b 97.2a
31.0 a 29.4a
16.6 a 16.3a
50.5 b 77.0a
formation of 'Cherry' was stimulated by the PTR. The number of fruits per plant under the PTR was almost doubled compared to the HTR, and the total yield increased accordingly by 82%. However, such a response was not observed in 'Moneymaker', and the total fruit yield of this cultivar under the PTR was similar to that under the HTR. The average weight of the 'Cherry' fruits was unaffected by the temperature treatments, while the average fruit weight of 'Moneymaker' decreased by almost 40% under the LTR. DISCUSSION
The temperature optima of the tomato plants vary according to the parameters observed, the stage of plant development and the cultivar (Charles and Harris, 1972; Aung, 1979). These differences were also observed in the present study. In cultivation of greenhouse tomatoes, maintenance of higher temperatures is recommended during the vegetative growth of the seedling before the first inflorescence is formed, with a further decrease in the night temperature (Picker et al., 1985). Thus, growing different cultivars and/or plants at different stages of development often requires a compromise
13
temperature regime. This may lead to losses in the potential yield. Our data show that interruption of the established temperature optima by short periods of sub-optimal temperatures did not result in decreased production, as exhibited (Table IV) for the split night-temperature regime reported previously (Gent et al., 1979). Thus, substantial savings of 30--35% in the greenhouse energy consumption may be obtained by using PTR. An additional benefit of 82% increase in yield was obtained with 'Cherry' tomato (Table IV). This increase in the tomato fruit production of 'Cherry' was due to the effect of the PTR on certain yield components. The first was the decreased number of leaves required prior to the formation of the first inflorescences (Table I). This developmental stage of the tomato plant usually has lower temperature requirements (Picken et al., 1985a). The second component affected was the number of flower trusses, which was increased by the PTR (Table III). This component is also promoted by lower temperatures (Aung, 1979). The most profound phenomenon was the increase in number of fruits (Table IV). The number of tomato fruits tends to decrease with higher temperature due to a higher rate of abortion (Charles and Harris, 1972). On the other hand, the vegetative growth of tomato plants is stimulated by higher temperatures. Thus, it is possible that under PTR, more developmental processes are exposed to optimal temperature conditions than under constant high or low temperatures. However, the mechanism of the pulsing effect and the physiological basis for the differences among cultivars, as well as the optimal length of the high and low temperature intervals, require further investigation. The described method of greenhouse heating (PTR) may be introduced as an economical tool for saving energy and as a way of increasing production in tomato plants as well as in many other greenhouse crops. REFERENCES Aung, L.H., 1979. Temperature regulation of growth and development of tomato during ontogeny. Proc. 1st Int. Symp. Tropical Tomato, Asian Veg. Res, Dev. Cent., Shanhua, Taiwan, pp. 79--93. Charles, W.G. and Harris, R.E., 1972. Tomato fruit-set at high and low temperatures. Can. J. Plant Sci., 52: 497--506. Gent, M.P.N., Thorne, J.H. and Aylor, D.E., 1979. Split-night temperatures in a greenhouse: The effects on the physiology and growth of plants. Conn. Agric. Exp. Stn. Bull., 181: 1--15. Hanan, J.J., 1979. Observation of low temperature effect on roses. J. Am. Soc. Hortic. Sci., 104: 37--40. Picken, A.J.F., Hurd, R.J. and Vince-Prue, D., 1985. Lycopersicon esculentrum Mil. In: A.H. Halevy (Editor), Handbook of Flowering. CRC Press, Boca Raton, FL, Vol. 3, pp. 330--346. Shanks, J.B. and Osnos, G.O., 1980. Growth of greenhouse roses at several split nighttemperature regimes. Hortic. Sci., 15: 587. Zieslin, N., Khayat, E. and Mor, Y., 1985. The response of rose plants to different nighttemperature regimes. J. Am. Soc. Hortic. Sci., in press. Zieslin, N., Khayat, E. and Yoger, S., 1985b. The response of tropical foliage and other pot-plants to various night temperature regimes. Hassadeh, 66: in press.
9
Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
THE EFFECTS OF VARIOUS NIGHT-TEMPERATURE REGIMES ON THE VEGETATIVE GROWTH AND FRUIT PRODUCTION OF TOMATO PLANTS
E. KHAYAT, D. RAVAD and N. ZIESLIN
Department of Ornamental Horticulture, The Hebrew University of Jerusalem, Rehovot 76100 (Israel) (Accepted for publication 8 May 1985)
ABSTRACT Khayat, E., Ravad, D. and Zieslin, N., 1985. The effects of various night-temperature regimes on the vegetative growth and fruit production of tomato plants. Scientia Hortic., 27: 9--13. The fruit production of tomato cultivar 'Moneymaker' was not reduced by interruption of the optimal night-temperature regime by short intervals of lower temperature. The same treatment increased the yield of 'Cherry' by 82% in the comparison with a constant night temperature of 18°C. The increase in yield of this cultivar was due to a larger number of fruits per plant. Interruption of the optimal night-temperature regime by a pulsing temperature regime (PTR) may be introduced as a method in the cultivation of greenhouse tomato plants for energy saving and for promotion of fruit-set in certain tomato cultivars. Keywords: energy saving; temperature; tomato. Abbreviations: HTR = high-temperature regime; LTR = low-temperature regime; PTR = pulsing temperature regime.
INTRODUCTION
Partial replacement of optimal temperature conditions by periods of suboptimal temperature is used for conserving energy in the cultivation of greenhouse crops (Gent et al., 1979). The response to this heating technique varied according to the plant species examined. A small effect was exhibited on the growth and fruit or flower production of tomatoes and lilies when a portion of the optimal night-temperature period was replaced by a lower temperature, a method known as "split night-temperature regime" (Gent et al., 1979). Flower production of roses was reduced and flowering was postponed by using this technique (Hanan, 1979; Shanks and Osnos, 1980). However, interruption of the night-temperature regime by shorter, but repetitive, intervals of sub-optimal temperature-pulsing temperature regime 0304-4238/85/$03.30
© 1985 Elsevier Science Publishers B.V.
10
(PTR) did not cause a reduction in the number of flowers of certain rose cultivars, while one of the cultivars examined even responded with an increase in the number of flowers formed (Zieslin et al., 1985a). Positive responses were also observed in preliminary experiments with some other plant species when PTR was used (Zieslin et al., 1985b). MATERIALS AND METHODS
Seeds of 2 tomato cultivars, 'Moneymaker' and 'Cherry 35070E Danmark' (Cherry 688, FA Israel) were sown on 28 December 1983. A night temperature of 18°C was maintained during the germination period. Following germination, seedlings with one true leaf were planted in 5-1 containers with a growth medium which contained peat-moss and volcanic scoria (1:1 v/v). The plants were irrigated once or twice daily with a nutrient solution containing microelements. The plants were transferred on 6 January 1984 to 3 greenhouse compartments with 3 different night-temperature regimes: (1) HTR, minimum of 18 + 1°C constantly (high-temperature regime), (2) LTR, minimum of 12 + I°C constantly (low-temperature regime), (3) PTR, 18 and 12°C repeated every 2 h (pulsing-temperature regime). The minimal and maximal day temperatures of 18 and 30°C, respectively, were maintained in all the 3 compartments. The data were collected individually from each plant; 12 plants per treatment. The statistical analysis was made by multiple range test, and figures accompanied by different letters are significantly different at P = 0.05. RESULTS
The number of leaves developed before the formation of the first inflorescence was reduced by LTR and by PTR in b o t h cultivars examined (Table I). Stem elongation of 'Cherry' was not affected by the different temperature treatments, and the observed differences in the final lengths were
TABLE I The influences o f n i g h t - t e m p e r a t u r e regimes o n the n u m b e r o f leaves p r e c e d i n g the form a t i o n o f t h e first i n f l o r e s c e n c e in 2 t o m a t o cultivars Night-temperature regime
'Cherry'
'Moneymaker'
C o n s t a n t at 18°C = HTR C o n s t a n t at 12°C = L T R 18/12 °C = PTR
10.7 a 8.4 b 8.6 b
8.0 a 7.2 b 7.3 b
11
insignificant (Fig. 1A). However, the stem length of 'Moneymaker' plants was significantly reduced by the LTR and to a greater extent by the PTR (Fig. 1B). In both cultivars the final number of leaves was reduced by LTR, but was n o t affected by PTR (Table II). The number of flower trusses of 'Moneymaker' was reduced by the LTR, while PTR had no effect on this parameter (Table III). A different response was shown by 'Cherry'. While the LTR did not affect the number o f flower trusses, an increase of 10% in this parameter was obtained under the PTR (Table III). The total fruit yield and some other parameters of tomato fruit production are summarized in Table IV. The data show the differences in the responses of the two cultivars to changes in the night-temperature regimes. Although the yield of 'Cherry' was not affected by the LTR, the yield of 'Moneymaker' was reduced by 23% in comparison with the HTR. The fruit I
,6° I
i
i
i
1
I
I
®'MON*EYM,K;R
CHERRY
'
' .
120
g :~LTR
z~
J L
7
L 14
I 24
I 30
1
37
l I I l I 48 56 7 14 24 DAYS FROM TRANSPLANTING
I
30
1
37
1
48
I
56
Fig. 1. The i n f l u e n c e o f n i g h t - t e m p e r a t u r e regimes o n the length o f t h e main s h o o t o f t o m a t o p l a n t s o f t w o cultivars: A, ' C h e r r y ' ; B, ' M o n e y m a k e r ' . o, 18°C = H T R ; *, 12°C = L T R ; *, 18/12°C = PTR. T A B L E II The i n f l u e n c e o f n i g h t - t e m p e r a t u r e regimes o n t h e n u m b e r o f leaves d e v e l o p e d o n the main s t e m o f t o m a t o plants. The figures are the average n u m b e r o f leaves p e r plant Night-temperature regime
'Cherry'
'Moneymaker'
C o n s t a n t at 18°C = H T R C o n s t a n t at 12°C = L T R 18/12 °C = P T R
30.0 a 27.5 b 29.5 a
28.7 a 26.8 b 28.0 a
12 T A B L E III T h e influence o f n i g h t - t e m p e r a t u r e regimes o n the n u m b e r o f f l o w e r trusses o n t o m a t o plants. T h e figures are average n u m b e r s o f f l o w e r trusses p e r p l a n t Night-temperature regime
'Cherry'
'Moneymaker'
C o n s t a n t at 18°C = H T R C o n s t a n t at 12°C = L T R 1 8 / 1 2 °C = P T R
6.6 b 6.0 b 7.3 a
6.8 a 5.6 b 6.6 a
T A B L E IV T h e e f f e c t o f t h e n i g h t - t e m p e r a t u r e regime o n various p a r a m e t e r s o f fruit yields o f tomato plants 'Cherry' and 'Moneymaker' Temperature regime
C o n s t a n t 18°C -- H T R C o n s t a n t 12°C = LTR 1 8 / 1 2 °C = P T R
Yield p e r p l a n t (g)
N u m b e r o f fruits per p l a n t
Av. fruit w e i g h t (g)
'Cherry'
'Moneymaker'
'Cherry'
'Moneymaker'
'Cherry'
'Moneymaker'
823 b
2027 a
49.0 b
25.1 b
16.7 a
80.6 a
909 b 1503a
1571 b 2267a
56.6 b 97.2a
31.0 a 29.4a
16.6 a 16.3a
50.5 b 77.0a
formation of 'Cherry' was stimulated by the PTR. The number of fruits per plant under the PTR was almost doubled compared to the HTR, and the total yield increased accordingly by 82%. However, such a response was not observed in 'Moneymaker', and the total fruit yield of this cultivar under the PTR was similar to that under the HTR. The average weight of the 'Cherry' fruits was unaffected by the temperature treatments, while the average fruit weight of 'Moneymaker' decreased by almost 40% under the LTR. DISCUSSION
The temperature optima of the tomato plants vary according to the parameters observed, the stage of plant development and the cultivar (Charles and Harris, 1972; Aung, 1979). These differences were also observed in the present study. In cultivation of greenhouse tomatoes, maintenance of higher temperatures is recommended during the vegetative growth of the seedling before the first inflorescence is formed, with a further decrease in the night temperature (Picker et al., 1985). Thus, growing different cultivars and/or plants at different stages of development often requires a compromise
13
temperature regime. This may lead to losses in the potential yield. Our data show that interruption of the established temperature optima by short periods of sub-optimal temperatures did not result in decreased production, as exhibited (Table IV) for the split night-temperature regime reported previously (Gent et al., 1979). Thus, substantial savings of 30--35% in the greenhouse energy consumption may be obtained by using PTR. An additional benefit of 82% increase in yield was obtained with 'Cherry' tomato (Table IV). This increase in the tomato fruit production of 'Cherry' was due to the effect of the PTR on certain yield components. The first was the decreased number of leaves required prior to the formation of the first inflorescences (Table I). This developmental stage of the tomato plant usually has lower temperature requirements (Picken et al., 1985a). The second component affected was the number of flower trusses, which was increased by the PTR (Table III). This component is also promoted by lower temperatures (Aung, 1979). The most profound phenomenon was the increase in number of fruits (Table IV). The number of tomato fruits tends to decrease with higher temperature due to a higher rate of abortion (Charles and Harris, 1972). On the other hand, the vegetative growth of tomato plants is stimulated by higher temperatures. Thus, it is possible that under PTR, more developmental processes are exposed to optimal temperature conditions than under constant high or low temperatures. However, the mechanism of the pulsing effect and the physiological basis for the differences among cultivars, as well as the optimal length of the high and low temperature intervals, require further investigation. The described method of greenhouse heating (PTR) may be introduced as an economical tool for saving energy and as a way of increasing production in tomato plants as well as in many other greenhouse crops. REFERENCES Aung, L.H., 1979. Temperature regulation of growth and development of tomato during ontogeny. Proc. 1st Int. Symp. Tropical Tomato, Asian Veg. Res, Dev. Cent., Shanhua, Taiwan, pp. 79--93. Charles, W.G. and Harris, R.E., 1972. Tomato fruit-set at high and low temperatures. Can. J. Plant Sci., 52: 497--506. Gent, M.P.N., Thorne, J.H. and Aylor, D.E., 1979. Split-night temperatures in a greenhouse: The effects on the physiology and growth of plants. Conn. Agric. Exp. Stn. Bull., 181: 1--15. Hanan, J.J., 1979. Observation of low temperature effect on roses. J. Am. Soc. Hortic. Sci., 104: 37--40. Picken, A.J.F., Hurd, R.J. and Vince-Prue, D., 1985. Lycopersicon esculentrum Mil. In: A.H. Halevy (Editor), Handbook of Flowering. CRC Press, Boca Raton, FL, Vol. 3, pp. 330--346. Shanks, J.B. and Osnos, G.O., 1980. Growth of greenhouse roses at several split nighttemperature regimes. Hortic. Sci., 15: 587. Zieslin, N., Khayat, E. and Mor, Y., 1985. The response of rose plants to different nighttemperature regimes. J. Am. Soc. Hortic. Sci., in press. Zieslin, N., Khayat, E. and Yoger, S., 1985b. The response of tropical foliage and other pot-plants to various night temperature regimes. Hassadeh, 66: in press.