Study On Effects Of NPK Ratio On Growth, Development And Metabolism Of Cucumber In Solar Greenhouse

Aimed at the practice of excessive and unbalanced using of chemicalfertilizer in solar greenhouse, based on the nutrient character of grennhousesoil sampled from Shouguang and Linzi of Shandong province, the soil-cultured and soilless-cultured experiments were carried out with "Xintaimici"cucumber(Cucumis Sativus L.) in solar greenhouse. Referring to the previousdata, eight treatments in each culture way were designed: Treatment 1(T1,J1)was the control and its NPK ratio was 1:0.5:1.2, the NPK ratios fromTreatment 2 to Treatment 8 were just as follows: 2:0.5:1.2, 4:0.5:1.2, 1:1:1.2,1:2:1.2, 1:0.5:2.4, 1:0.5:4.8, 1:1:0.3. The effects of different NPK ratio oncucumber growth, development and physiological metabolism were studied inthe and the main results were as follows:1. Adding P could improve greatly the growth and yields of cucumber; Addingthe rate and ratio of N, P decreased the contents of soluble protein and vitaminC in cucumber fruit, but increased the soluble sugar content and nitrate contentremarkably. Adding K improved soluble sugar content, decreased the nitratecontent in fruit, and the more rate and ratio of K used, the more obvious theeffects were.As a result, in the experiments, the best NPK ratio was 1:2:1.2.2. Increasing the ratio of N or P improved chlorophyll a and chlorophyll bcontents, and increasing K improved carotene content in cucumber leaf.Adding N, P were benefit to leaf photosynthesis, as a result, ΦPSⅡandFv/Fm roused significantly, adding phosphorus had more remarkable effect onphotosynthesis, but adding K was less effective.3. Adding N, P could improve cucumber root activity, increased the absorptionof N, P and Mg, decreased that of K; Adding N improved the contents of Ca,Fe, Mn and Zn in leaves, and adding P accelerated absorption of cucumberroot to Fe. Adding K decreased the contents of N, P in leaves, but increased K,Fe content, contents of Ca, Mn and Zn decreased at the same time.4. Adding the rates and ratio of N, P, and K increased the activity of SOD incucumber leaves and root. The changes of POD activity were complex, maybeP played the more important role. The treatments of adding N or P and theTreatment 7 improved CAT activity in leaves and root of cucumber.