Effects of Growth Regulators on Quality of Cucumber(C.sativus L.) Seedlings by Plug Seedling

[Objective]The aim was to study the effects of daminozide(B9),paclobutrazol(PPP333) and cycocel(CCC) quality of cucumber seedlings by plug seedling.[Method]There were 12 treatment groups and 1 control group in the test.B9 concentration was 50,100,500,1 000 mg/L respectively,PPP333 concentration was 5,10,30,50 mg/L respectively,CCC concentration was 20,50,80,100 mg/L respectively.The growth regulators were sprayed at the first and the second central leaf appearing,namely about 10 and 15 days after seedling emergence.The plant height,stem diameter,maximum leaf area,dry and fresh weight of overground part and underground part,root volume,chlorophyll content and electrical conductivity of each treatments cucumber were investigated at 3 leaves and 1 central leaf.[Result]The results showed that B9,PPP333 and CCC could all control the excessive growth of the seedlings effectively,promoted root development,improved the physiological function of leaves and the healthy seedling index,while different growth regulators had different suitable concentration and usage time.The usage time of B9 and PPP333 were really strict.Delaying or advancing could both affect seedlings quality.Thereinto,B9 was suitable for using at about 10 days after seedling emergence and the optimal concentration was 500 mg/L,while the PPP333 was suitable for using at 15 days after seedling emergence and the optimal concentration was 10-30 mg/L,and the best concentration was 20 mg/L.The usage time of CCC was not that strict,it could be used at 10-15 days after seedling emergence,and the optimal concentration was 500 mg/L.[Conclusion]The study confirms the optimal concentration and usage time of B9,PPP333 and CCC in cucumber plug seedling,provides a theoretical and practical basis for industrial growing seedling of cucumber.