Nutritional Effect Of Selenium On Tartary Buckwheat

The buckwheat is dicotyledonous polygonaceae plant, which is considered as the best organic food in the 21st century by the International Agricultural Nutrition and the Health Organization. The buckwheat is widely grown in some places in Chongqing, but because of the aged and combination variety, fragmentary and disperser planter and backwardness management, the output of the buckwheat is low. The regional advantages of buckwheat production in Chongqing can not be displayed well. The research of buckwheat in our country concentrates in the product processing now, but basic research, such as applying fertilizer is lacking and little research is considered on applying trace elements fertilizer of buckwheat to optimize the nutriments structure. Selenium is an essential trace element. Selenium in 72% areas of China is low or deficient, which lead to various kinds of endemic diseases. Buckwheat contains higher selenium, so studying the selenium nutritional effects of physiological mechanism from the perspective of nutritional control has a very important significance and will increase the yield, optimize the nutritional structure and improvement the development of buckwheat. It will give the green food stronger health function and market vitality. In this paper, the NO. 1 golden buckwheat, a kind of local species in Hechuan zone of Chongqing, was employed. Pot experiments in four selenium levels and chemical analysis methods were adopted to study the effect of selenium on buckwheat growth, nutritional effects and character of soil. The main results were as follows:1. Early growth of buckwheat was restrained after applying Se, and plant height and dry weight all dropped. However, plant height under the 0.5mg/kg treatment and dry weigh under the 0.5 mg/kg and 1 mg/kg treatments were all higher than those of the control. The results showed that selenium improved growth in the late period. Applying Se could improve growth of overground part, but root growth was restrained and made root/canopy ratio little. Compared with the control, kernel number head, yield, weight and 100-kernel weight all increased markedly under the 0.5 mg/kg and 1 mg/kg treatments, which respectively increased 132% and 41%. When the concentration of Se was 2.0mg/kg, the growth and development of buckwheat were seriously restrained and the yield decreased, and the buckwheat seemed to be poisoned. It was suitable for buckwheat growth when the concentration of Se was 0.5mg/kg or 1.0mg/kg, and 0.5 mg/kg concentration range was considered the optimum density scope.2. Selenium level of buckwheat was significantly improved after applying Se, but the content of selenium was different in the buckwheat organ at different growth stage. Order of content of Se in the buckwheat organ at the seedling stage was as follow: roots＞leaves＞stems. The order of the selenium content in the organs of buckwheat at the flowering stage was: flowers＞roots＞leaves＞stems. The highest and lowest selenium content was respectively in the flower and the stem. Transfer law of selenium in the buckwheat was from the underground to the organs of the ground and from nutrition to the genital organ. Leaves and stems were the main storage organs of selenium in the buckwheat. Selenium contents in the leaves and stems almost were 72-79% of the whole plant., the storage proportion of selenium in the grain which was a direct use part for humans was different under different Se level and the order was as follow:T2＞T3＞T4＞T1.3. Accumulation of dry matter in buckwheat mostly happened at the middle and late stage of buckwheat development, and the peak value of accumulation rate was on the 60th Day. After applying Se, the accumulation rate of dry matter reduced slowly at the middle and late stage, which meant that the growth period of buckwheat was extended. Selenium accumulated constantly in the whole growing period of buckwheat. The accumulation rate of selenium was maximum at the mature stage of buckwheat at the low selenium concentration. There were great differences on the accumulation rate of selenium in organs among different treatments. It showed that the transport process of Se in plants was complex. However, the law of change was approximate at 0.5-1.0mg/kg selenium concentrations. The accumulation concentration of Se in the different organs was leaves＞stems＞seeds＞roots＞blossoms. Employing Se at 0.5-1.0mg/kg concentration could enhance dry matter accumulation of buckwheat, and it could also enhance Se accumulation of buckwheat. Within this concentration range of Se, the extra significant positive correlation(r=0.9748^**) was observed between dry matter accumulation and Se accumulation.4. The Se content of the Buckwheat seeds increased by 8.8-11.5 times after applying Se. Applying Se also increased the content of N, P, Ca, Zn and Mn, while decreased the contents of Cu and Fe. Se content of buckwheat seeds had significant positive correlation with the P and Ca content, extremely significant positive correlation with the Zn content, and it had significant negative correlation with the Cu and Fe content. The starch content of buckwheat seeds decreased, while the crude fat and crude protein content increased after employing Se. The starch, crude fat and crude protein contents were all increased remarkably after applying Se at 0.5-1.0mg/kg concentrations. Generally speaking, applying Se improved the nutrition structure of buckwheat seeds and its quality.5. Available Se content in soil increased at parabola after applying Se. Relativity between plant selenium content and the soil available selenium content was remarkable (r=0.950^*). Simultaneously, applying Se could increase the content of available P and available K, but the influence to available N was not orderly.