Effect Of Potassium Level On Cucumber Growth, Physiological Indices And Yield Under Sub-optimum Temperature And Light Intensity

Longterm sub-optimum temperature and light intensity were main factors to effected cucumber growth in northern China Greenhouse. Effect of potassium level on cucumber growth, physiological indices and yield under sub-optimum temperature and light intensity were studied to provide a theoretical basis for the application of potash fertilizer.The seedings of cucumber ‘Zhong Nong No.26’ were used as material. The normal temperature(25-30℃/15-20℃)and light intensity(600-800μmol/m2·s)were as control; After 5, 10 and 15 days of the suboptimum temperature(15-18℃/10-12℃)and light intensity( 165-300μmol/m2·s), the growth was detected with different K fertilizer treatment.The test were made in greenhouse, Studies of K+concentration which were 6,9,12, 15mmol/L four potash treatments on growth and yield and quality of cucumber under sub-optimum temperature and light intensity were made.The seedling test results showed that with the increase of potash fertilizer, the growth of cucumber seedlings first rise and then decreased. The plant height, shoot ratio, chlorophyll content, the root activities and protective enzyme contents were obvious increased under adding twice the potash treatment compared with suboptimum temperature and light intensity normal Potash treatment. The activities of plasma membrane H+-ATPase of cucumber seedling leaves were rise and then decreased after 5, 10 and 15 days of the treatment and the activities of leaves were higher than the roots. Adding twice the potash deal was 4.62μmol·Pi/mg·h after 15 days treatment,which was 47.90% for normal processing of potash, it was just 2.26μmol·Pi/mg·h。Accumulation of mineral elements were significant differences with the increase of the concentration of mineral elements. K element accumulation in blade was higher than in stem, root, while Ca element was opposite. Mg element changed a little in various parts of the plant. It indicated that the roots of cucumber seedlings preferentially absorbed N elements and leaves for Ca elements to met growth under sub-optimum temperature and light intensity. Increasing potassium promoted the growth of cucumber seedlings. Adding twice the potash treatment and the potassium ion concentration is 12mmol/L, cucumber seedlings growing best.The results of the test results were the same with the seedling test results. the potash treatment and the potassium ion concentration is 12mmol/L, cucumber seedlings growing best and the root activities were highest. The activities of plasma membrane H+-ATPase of cucumber leaves and roots were rise and then decreased. Accumulation of mineral elements were significant differences in leaves, stems, roots and fruits with the increase of the concentration of mineral elements. K element accumulation in blade was higher than in stem, root, while Ca element was opposite. Mg element changed a little in various parts of the plant. Potassium fertilizer can increase fruit weight and yield of cucumber, improve the quality of cucumber, the most significant effect of treatment was the potassium ion concentration is 12mmol/L, Community production was 12.28% higher than the control.Comprehensive the results, adding certain potash promoted the growth of cucumber, yield and quality also improved.