| To solve the problem of melon seedlings growth inhibition,low quality and high node position of the first fruit caused by high temperature environment which is common in the summer melon seedling production,and growth inhibition,low quality and low node position of the first fruit caused by low temperature environment which is common in the early spring melon seedling production.This research studied the effect of short time cold or warm shock on growth,stress resistance and the node position of flowers of melon seedlings.1.The experiment was carried out,in which the average outdoor temperature is 32 ° C,the highest temperature is 49 ° C,the lowest temperature is 26 ° C in the summer and autumn and seedlings were treated every day in summer and autumn.The results showed that: in winter and spring,the treatment of 35? warm air-shock?20 minute with 9 times and 35? warm water-shock with 9 times relieved the growth inhibition of melon seedlings' shoot and root in low temperature condition,promoted seedling growth,improved the expansion of leaves and development of roots.Meanwhile,it increased stress resistance and elevated the node position of the first fruit.The leaf area,total root length,root surface area,root tip and seedling index of melon seedlings treated with 35 ? warm air for 20 minutes and 9 times were 71.6%,53.3%,43.9%,45.2% and 68.4% higher than the control,respectively;activity of SOD,POD and CAT was 23,181 and 288 U/m L,respectively;male flower buds were 5.6 knots lower than the control,and the node position of the first fruit was 7.6 knots higher than the control.The leaf area,total root length,root surface area,root tip and seedling index of melon seedlings treated with warm water at 35 ? for 9 times were 11.5%,61.1%,24.7%,19.7% and 82.3% higher than the control,respectively;activity of SOD,POD and CAT was 19,190 and 238 U/m L,respectively;the male flower buds were 4.5 knots lower than the control,and the node position of the first fruit was 6.9 knots higher than the control.With warm air treatment,it is necessary to increase the accumulated thermal of effective shock of 823.74 ? / h than the control treatment to increase the node position of the first fruit of the winter and spring melon to the optimum node.Under the warm water treatment,it is necessary to increase the accumulated thermal of effective shock of 1776.28 ? / h than the control treatment to increase the node position of the first fruit of the winter and spring melon to the optimum node.2.the experiment was carried out,in which the average outdoor temperature in winter and spring is 17 ° C,the highest temperature is 38 ° C,and the lowest temperature is 3 ° C and every two days on sunny and every three days on rainy days in winter and spring.The results showed that: while in the summer and autumn melon seedling production,treatment of 10? cold air-shock?30 minute with 9 times and 10? cold water-shock with 9 times relieved the growth inhibition of melon seedlings' shoot and root in high temperature condition,promoted seedling growth,improved the expansion of leaves and development of roots.Meanwhile,it increased stress resistance in summer and lowered the node position of the first female flower in summer.The leaf area,total root length,root surface area,root tip and seedling index of melon seedlings treated with 10 ? cold air for 30 minutes and 9 times were 48.4%,58.7%,33.2% and 57.5% higher than the control,respectively,the seedling index was 2.08 times than the control;activity of SOD,POD and CAT were 14,50 and 115 U/m L,respectively;male flower buds were 3.3 knots lower than the control,and the node position of the first fruit was 7 knots lower than the control.The leaf area,total root length,root surface area,root tip and seedling index of melon seedlings treated with cold water at 10 ? for 9 times were 50.5%,58.7%,53.6% and 72.8% higher than the control,respectively,the seedling index was1.05 times than the control;activity of SOD,POD and CAT was 21,135 and 190 U/m L,respectively;the male flower buds were 3 knots lower than the control,and the node position of the first fruit was 7.3 knots lower than the control.With cold air treatment,it is necessary to decrease the accumulated thermal of effective shock of 1096.36 ? / h than the control treatment to increase the node position of the first fruit of the winter and spring melon to the optimum node.Under the cold water treatment,it is necessary to decrease the accumulated thermal of effective shock of 106.8 ? / h than the control treatment to increase the node position of the first fruit of the winter and spring melon to the optimum node.This experiment provides theoretical and technical support for improving the quality of melon seedlings,promotion of stress resistance,regulation of the node position of flower and energy-saving control technology for factory melon seedling production. |
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