Study On Screening Of Low P And K Tolerant Sweet And Waxy Corn Varieties And Its Mechanism

Three treatments N1P1K0(N and P fertilizer were applied without K), N1P0K1(N and K fertilizer were applied without P), N1P1K1(NPK fertilizers were applied) were established in order to study the low P and K tolerant traits of 19 sweet and waxy corn varieties in green house. 19 varieties were divided into three categories: low P and K tolerant varieties, low P and K medium tolerant varieties, Low P and K sensitive varieties by fuzzy comprehensive evaluation and cluster analysis based on the morphological and physiological characteristics of the varieties.Five sweet and waxy maize varieties screening from Seedling experiment were used for field trials to study the effects of substances accumulation physiological, photosynthetic physiology, resistance physiology, yield and its component factors under low P and K stress. The research indicates:1.The results of green house showed: The plant height, stem diameter, root volume,root number, root dry weight and shoot dry weight, root P and K accumulation, shoot P and K accumulation of 19 varieties reduced. there is a significant difference of P and K resistance capability of varieties.2.High variation coefficient was used as an indicator of low P and K tolerant capability. Therefore, this test selected the root volume, root dry weight, shoot dry weight,root P and K accumulation, shoot P and K accumulation as the evaluation index.3.The results of fuzzy comprehensive evaluation of agronomic traits showed: low K stress on Jinkenuo 209, Meiyuxiangtian 16 th, Huameitian 8th affectted less than Huami,Yanhejin 2005. Low P stress on Jinkenuo 209 and Huameitian 8th affected larger than Meiyuxiangtian 16 th, Huami, Yanhejin 2005.4.P and K promote not only the accumulation of dry matter, but also can increase plant N, P, K accumulation in sweet,waxy corn. Low P, K stress will reduce the accumulation of sweet, waxy corn dry matter, and also can reduce plant N, P, K accumulation.5.There are a significant differences of Chlorophyll content among different varieties under the same treatment, there are also among different treatments of the same varieties.There are no difference of chlorophyll content of the same varieties in different periods.Chlorophyll content of Yanhejin 2005 was less affacted than that of other varieties underPhosphorus Deficiency. Chlorophyll content of Meiyuxiangtian 16 th was less affacted than that of other varieties under potassium deficiency,while chlorophyll content of Jinkenuo209 was more affected than that of other varieties under P and K deficiency. Low P, K stress will reduce the photosynthetic rate, and had a significant differences among different varieties. Photosynthetic rate of Yanhejin 2005 was more affacted than that of other varieties under low P, K deficiency. while the photosynthetic rate of Jinkenuo 209 was less affacted.6.Low P, K stress inhibited the activity of superoxide dismutase. Superoxide dismutase activity decreased from jointing to maturity stage. Huameitian 8th was more affected under low K stress, while Huami was less affected. Yanhejin 2005 was more affected under the low P stress, while Jinkenuo 209 was less affected. There are differences of malondialdehyde content among different varieties.malondialdehyde content of sweet,waxy corn increased. Meiyuxiangtian 16 th was more affacted under low P, K stress, while Huami was less affacted. There was a significant differences of proline content among different varieties under low P and K stress and the same treatment, there are also among different treatments of the same varieties except jointing stage. Sweet and waxy corn proline content increased gradually from the jointing stage to maturely. Proline content of Huami was more affacted, while Huameitian 8th was less affected under low P, K stress.