A Study On Physiological And Biochemical Characteristics Of Broad Bean Under Al And Water Stress

Broad bean (Vicia Faba L) is herbage legume which grows one or two years. Broad bean is used broadly, not only as food but also as medicine. It has a high economic value and possesses the fixation of nitrogen. Broad bean can be inter-species with other crops which is conducted to improve soil fertility. Most of broad bean is grown on the acid soil in the south of china. Its growth and yield is affected by the aluminum toxicity and water stress in winter.The secretion of organic acid was considered as an important mechanism for the plant to resist aluminum toxicity. Many crops had been studied, for example wheat, soybean, buckwheat and stylosanthes gracilis. But at the present time, there was no study for mechanism to resist aluminum toxicity for broad bean. This paper studied the mechanism of resistant Al toxicity for broad bean under Al stress using four variety, yundou 83324, 2003-456,2003-7290 and 8363. The secretion of oxalic acid and citric acid in broad bean under Al stress was discovered by thin layer chromatography. The secretion of broad bean could effectively mitigate the damage of alfalfa root caused by Al toxicity. The strongest variety to resist Al toxicity in four varieties were yundou83324.In addition, broad bean also secreted a amount of alanine under Al stress.The development and growth of broad bean was great affected by water stress. The study of water stress on yundou 83324 with stronger resistant Al toxicity was conducted. Broad bean damage under water stress was midigated through stomatal closure, which led to reduce leaf evaporation. Biomass as well as the rate of aboveground and underground dry weight was seriously affected by water stress. The fresh weight, the dry weight and the leaf area in control were 2,3.5 and 2 times higher than that under water stress,respectively. The rate of the root and aboveground biomass under the water stress was significantly higher than the control. The praline content at branching phase and flowering phase under water stress was increased by 4-11 and 2.3-4.2 times than control,respectively. Under the water stress, Plant potassium content was slightly higher than the control,but sodium content significantly higher than the control.The drought-resistant protein which in broad bean leaves was induced by water stress. The size was 88Kda and 60Kda,47Kda, respectively.Taken together, broad bean could secret oxalic and acid citric acid to resist Al oxicity under Al stress. Under water stress,broad bean could close the stomatal,increase the rate of the root and aboveground biomass and the content of proline in broad bean as well as induce rought-resistant protein to resistant to the water stress.These results provides theoretical foundation for taking agricultural measures to improve aluminum toxicity and tolerance to drought for broad bean and further for enhancing plant resistance through plant genetic engineering.