Effect Of Nitrogen Fertilizer On Key Enzymes Activities Of Nitrogen Metabolism And Yield And Quality Of Kidney Bean

Kidney bean(Phaseolus vulgaris L.) is rich in nutrition, with high contents of protein and carbohydrates. It is one of the main coarse cereals and economic crops with a large planting area in China. Heilongjiang province is one of most important production area as well as the largest exportation province of such a crop in China with a yearly exportation amount of about one and a half of the total national exportation. Nitrogen is important in terms of plants growth since it is a constituent part of living substances such as protein, nucleic acids and phospholipids.In this paper, four varieties, Pinyun2, British red kidney bean, Longyun6and Longyun4, were used as experimental materials, and five nitrogen fertilizer treatments such as without nitrogen(NO),15kg(N15),30kg(N30),45kg(N45),60kg(N60) per hectare) were designed to systematically study the effect of nitrogen on key enzymes activity of nitrogen metabolism, chlorophyll content, nitrogen efficiency, yield and grain nutrition quality of kidney beans. Research results clarified the mechanism of grain protein formation, the rules of activity changes of key enzymes such as nitrate reductase (NR)、glutaamine synthetase(GS)、glutamate oxaloacetate transaminase(GOT) and glutamate pyruvate transaminase(GPT) under different nitrogen rate. It revealed the regulation effect of nitrogen application rate on the yield and quality of kidney bean and provided theory basis for reasonable application of nitrogen for production and quality improvement.Conclusions are listed as follows:1. The chlorophyll content in functional leaves of the four varieties presented a single peak curve during the growth period, and reached its highest at the pod bearing stage; The activities of NR, GS, GOT and GPT in functional leaves of the four varieties showed a single peak curve during the whole growth stage. The activity of NR reached its peak at the flowering stage, while other enzymes under different nitrogen application reached their peaks at the pod bearing stage; A rates of30kg pure nitrogen per hector can effectively improve the chlorophyll contents, NR, GS, GOT and GPT in kidney bean leaves.2. The nitrogen uptake amount of the four varieties increased with the accumulation of dry matter; nitrogen uptake of Pinyun2, British red kidney bean and Longyun6were at a high under N45treatment in each period; for Longyun4, nitrogen uptake of N30was higher than other treatments during different growth period; The recovery efficiency of N30was higher than other treatments in the four varieties; But low nitrogen treatment was positive in improving agriculture utilization efficiency of kidney bean; With the increase of nitrogen rates, nitrogen partial productivity was reduced; Physiological utilization of Pinyun2and British red kidney bean hit the highest at N15, while that of Longyun6and Longyun4reached their peaks at N60and N30respectively.3. The grain protein contents of Pinyun2and Longyun4presented bimodal curve after podding, peaks appeared on the21st day and the35th day after podding; while grain protein contents of British red kidney bean and Longyun6presented single peak curve after podding, which appeared on the28th day after podding; For Pinyun2, Longyun6and Longyun4, the grain protein contents were higher than other treatments under N30treatment, while the grain protein content in British red kidney bean shows its highest value under N45tretment.4. The yield of the four varieties was the largest under N30treatment. Via regression fitting equation it can be calculated that the ralations is close between Nitrogen fertilizer and yield. The best rates for nitrogen application were:39.01kg/hm2,29.82kg/hm2,33.72kg/hm2, and32.15kg/hm2respectively for Pinyun2, British red kidney bean, Longyun6, Longyun4, and theoretically the highest yields were respectively2795.16kg/hm2,2583.24kg/hm2,2596.39kg/hm2,2762.43kg/hm2.5Considering the grain nutritional quality of kidney bean, the effect for N30treatment to protein, straight starch, amylopectin, total starch and crude fat is best.6Through related analysis we know that the relations between the chlorophyll content, activities of NR, GS, GOT and GPT enzyme of kidney bean and the grain protein or starch content and yield and yield formation factors are close.