Abstract:

In order to study the effect of GA₃ on cucumber in greenhouse. Fruiting cucumber cv.‘Zhongnong 26’was selected and different concentration 0（control），10，50，100 and 200 mg · L^-1 of gibberellin（GA₃）was applied to plant as spray and water was applied in control in greenhouse. The effect of GA₃ on physiological characteristics，yield and quality of cucumber were studied. The results showed that foliar applied GA₃ promoted the growth of cucumber compared with the control. Plant height，stem diameter，number of leaves and pigment content，net photosynthetic rate（P_n）as well as contents of N，P，K，Ca，Mg and Fe of cucumber were highest treated with 50 mg · L^-1 GA₃. The content of chlorophyll a and b，content of carotenoid and P_n treated with 50 mg · L^-1 GA₃ was increased by 27.16%，24.22%，29.24% and 22.44% respectively compared with that of control. Application of GA₃ also increased the fruit setting rate，number of fruits and yield per plant significantly. The 24% increase was recorded in yield of cucumber treated with 50 mg · L^-1 GA₃（18.22 kg · m^-2）compared with control. In addition the quality of cucumber was improved. The results indicated that the adverse effects of suboptimum temperature and light condition in greenhouse on cucumber in early spring could be alleviated by foliar applied GA₃ and the best concentration was 50 mg · L^-1.

Key words: cucumber, gibberellin, greenhouse, growth, yield