Accumulation Of Buckwheat Flavonoid And Protein And Regulating Effect Of Nitrogen And Phosphrous Fertilizer

Buckwheat is one of the staples in alpine region and areas with poor soil. Rich in flavonoid which is absent in other food crops, and protein whose content is higher than that of rice, wheat and maize and property is distinctive, buckwheat has important nutritive and medicinal value. At present, researches on flavonoid and protein focus on the extraction methods and nutrition determination, the improvement of contents, furthermore improving its processing and utilization is great urgent.In order to provide foundation for scientific management and production of high quality buckwheat, this study investigated the subunit property of buckwheat protein component, analyzed the dynamics of flavonoid and protein content with seeds maturing, and the effect of ratios of nitrogen and phosphrous on the content. It got the following main conclusions:1. Subunits composition of albumin, globulin and glutamine of common and tartary buckwheat,two cultured species,were determined using SDS-PAGE method. The results showed that high polymorphism was revealed among different common buckwheat cultivars while that among tartary buckwheat was limited. The albumin of buckwheat was composed of subunits with low molecular weight. Common buckwheat globulin was composed of 5-12 subunits from low to middle molecular weight whereas only 8 subunits constituted tartary buckwheat globulin. Common buckwheat glutelin was composed of 3-5 subunits with molecular weight ranging within 43-66.2kD. Tartary buckwheat glutelin was composed of 2 subunits whose molecular weight ranged within 31-43kD.2. Flavonoid content of common buckwheat seed was higher in the early grain-filling stage, and slowly decreased before rising at the seed maturing stage; Flavonoid content of tartary buckwheat was also higher in the early grain-filling stage, and gradually decreased. At the maturing stage, the flavonoid content was slightly increased.3. The dynamics of albumin and globulin content of common buckwheat and tartary buckwheat showed similar tendency. Albumin content was higher at the early grain-filling stage, and gradually decreased with seeds maturing; Globulin content was lowest and a negligible uptrend was observed in the grain-filling stage; Prolamin content of common buckwheat was also lower and a slightly downtrend was observed, glutamine content was higher with an increasing trend, but declined at the late stage of grain-filling stage; a tendency of"low, high, low"was observed for glutamine content of tartary buckwheat,which was also applicable to prolamin content.4. Flavonoid content of leaves and stems in development stage decreased with high level of fertilizer. High level of fertilization had a more negative effect on the flavonoid content of common buckwheat leaves than that of stems, a more negative effect on the flavonoid content of common buckwheat leaves than that of tartary buckwheat leaves, and an insignificant negative effect was also observed on the tartary buckwheat stems. In addition, because of tolerance to barren soil for a long time, nitrogen utilization of buckwheat is inefficient; therefore fertilization was not an ideal way for improving flavonoid content.5. Content of protein component of common buckwheat seed was more easily affected by P compared with N, and the demand of P was different, its globulin content was improved with higher level of P, which was not favorable to gliadin accumulation; As for tartary buckwheat, its globulin and gliadin content was more easily affected by fertilization level compared with albumin, moreover, moderate level of nitrogen and phosphorus was favorable to the accumulation of globulin and gliadin. However, fertilization level had no significant impact on the glutamine content of common buckwheat and tartary buckwheat.