Abstract:

【Objective】 To investigate the response of fruit endogenous hormone to different night temperatures and the relationship with fruit development, the effects of different night temperatures on the content of endogenous hormone were studied.【Method】 Endogenous hormone contents in fruit during expanding were determined utilizing HPLC and the relationship between endogenous hormone and increment rate of single fruit were analyzed. 【Result】 The results showed that endogenous GA3 and ZT had peaks at prophase of fruit expanding period. IAA climbed the highest position in the later of fruit expanding period while ABA remained low all long. What was more, the content of endogenous hormone had a great changer after treatment with different night temperatures. Compared to other treatments, GA3, ZT, IAA reduced in evidence and GA3/ABA, ZT/ABA was also reduced significantly, and ABA increased at the last stage of fruit development after 9℃ in night with the extraordinary significant difference, while GA3 and GA3/ABA was smaller after treatment of 18℃in night than that of 15℃ and 12℃. Otherwise, endogenous hormone had no obvious change between 15℃ and 12℃ in night. In addition, the analysis of the relationship between fruit endogenous hormone and the increment rate of single fruit indicated that there existed an extremely positive significant linear relationship between GA3/ABA and increment rate of single fruit in different night temperatures, with determination slops smaller under unsuitable night temperature, especially 9℃. However, except for 15℃ and 18℃, there was no significant linear relationship between ZT/ABA and increment rate of single fruit. 【Conclusion】 In a word, these results suggested that different night temperatures had different effects on endogenous hormone. Otherwise, decreased fruit development in unsuitable night temperature may not only have relevance to GA3 and GA3/ABA, but also be affected by other factors.

Key words: melon (Cucumis melo L.)')">melon (Cucumis melo L.), night temperature, fruit development, endogenous hormone