Studies On Mechanism Of Cucumber (Cucumis Sativus L.) "Blunt With Blossom" In Greenhouse

In this research, we selected JinChunNO.3, TM and dwarfNO.1 as experimental and studied on the effect of different sunshine hours, different temperature and different sowing time on blunt with blossom and studied on relationship between five endogenous plant hormones and blunt with blossom.. The detail results indicated:(1) Different sowing period had a great affect on JinChunNO.3, The blunt with blossom proportion of this species was very low in spring sowing, but the blunt with blossom proportion was very high, up to 89.2% in autumn sowing. Sowing time has a little affect on TM and no affect on dwarfNO.1.(2) The relationship with different species and blunt with blossom indicated: JinChunNO.3 is easier to blunt with blossom, TM is contrast, The rate of blunt with blossom of dwarfNO.1 is 100%.(3) The blunt with blossom has closely relationship with the environment also except for variety. The continuous low temperature and short sunshine is a main factor leading to cucumber blunt with blossom in greenhouse. However, higher temperature and longer sunshine is not benefit to blunt with blossom for cucumber. The low temperature critical value is about 10℃±1℃; The short sunshine critical value is about 7 hours.(4) The five hormones expressed the likely distribution in cucumber. Their contents is all high in up and young tissues ( stem apex, up leaf) higher and is lower in down tissues ( except ETH and ABA).When JinChunNO.3 is sowed in spring and autumn, the change tendency of the five hormones along with growth period indicated: ETH had a closely relationship with blunt with blossom, During all growth period, the blunt with blossom is serous when ETH content is low. High ETH content is benefit to blunt with blossom as ETH. Only is the affect efficiency different with ETH. High level GA3, especially in middle and last growth period inhibited blunt with blossom. On the contrary, If GA3 level is low during middle and last period the blunt with blossom happened seriously. The blunt with blossom is not easy to happen when IAA content is higher. But IAA content shouldn't too high and should have a threshold value. The(5) affect of ZR on blunt with blossom is very similar with GA3 and the higher level during middle and last period also inhibited the happen of blunt with blossom. ABA may be has a little relationship with blunt with blossom.(6) The analysis on changes of five hormones content in different species and the same sowing period along with the growth period indicated: The affect of the other four hormones on blunt with blossom is mainly the same as the affect in (5), except IAA.(7) The affect of rate of among five hormones on blunt with blossom in the same sowing period (in autumn) and different species (JinChunNO.3 and TM) showed: The ratio of GA3 and ETH had a closely relationship with blunt with blossom. When this ratio is high, blunt with blossom is not easy to happen and when it is low, blunt with blossom is easy to happen.