Preliminary Study On Physiological And Biochemical Characteristics Of Common Buckwheat During Grain Filling

The physiological and biochemical characteristics in grains including grain filling, starch accumulation and the key enzyme activity involving in starch synthesis of different branchs of common buckwheat at different flowering stage exposing to different hormone combinations were investigated in this study using different cultivars.The main results were as follows:1 Analysis of grain filling characteristics of different branchPot experiments were performed to study grain filling process of grains in different branch of Fengtian 1 by using Richards equation. The results showed that the grain filling process followed a slow-fast-slow pattern. The initial grain filling potential(R0), date reaching the maximum grain-filling rate(tmax.G) and maximum grain filling rate(Gmax) showed the maximum values in the top branches, and the minimum values in the bottom branches. The contribution to endosperm weight during grain filling was followed by the order of middle stage>later stage> earlier stage.2 Analysis of grain filling character at different floweringPot experiments were performed to study fresh grain weight, grain moisture and grain filling process by Richards equation at different flowering stage of Fengtian1. The results showed that the fresh grain weight increased during grain filling, then decreased at the later stage, while the grain moisture content was declined during grain filling. The pattern of grain filling process followed a "S" curve. The R0,tmax.G and Gmax showed the largest values in treatment 2(flowing time was at October 7), treatment 6(flowing time was at October 19)and treatment 1(flowing time was at October4) for treatment1, respectively. The contribution to grain weight was followed by the order of middle stage>later stage> earlier stage excluded the treatment 6.3 Analysis of grain filling character of 2 common buckwheatTwo common buckwheat varieties Fengtian1 and Tongliaobendixiaoli were used as experimental materials to study their grain filling process. The results showed that the filling process was followed as a "S" curve. Fengtian1 showed the largest values of the R0 and tmax.G, while when the values of Gmax and grain filling rate reached the maximum, Tongliaobendixiaoli showed the larger values of growth and grain filling rate to final value of grain(I). The maximum value of starch synthase activity was at 7 days after flowering in Fengtian1,at 14 days after flowering in Tongliaobendixiaoli, while the minimum value of starch synthase activity at 21 days after flowering in Fengtian1, at 28 days after flowering in Tongliaobendixiaoli. The minimum value of ADP-glucose Pyrophosphorylase activity was at 14 days after flowering in Fengtian1, at 28 days after flower in Tongliaobendixiaoli. The content of total starch, amylose and amylose of two varieties showed a gradual upward trend, but when reached a certain level, the increasing of the amount almost stopped.4 Analysis of physiological and biochemical characteristics of common buckwheat during grain fillingThe common buckwheat varieties Fengtian 1, Yuqiao 4, Dingtianqiao 2 and Tongliaobendixiaoli were used as experimental materials to study their physiological and biochemical characteristics during grain filling. The results showed that the chlorophyll content and chlorophyll a/b values in section 3 and 4 leaves were gradually decreased during grain filling, the soluble sugar and soluble protein content in mid grain filling stage were higher. The pattern of grain filling process of all varieties showed a "S" curve. Yuqiao 4 showed the largest values of R0, Fengtiao 1 showed the largest values of tmax.G, while Dingtianqiao 2 showed the largest values of Gmax. The starch synthase activity was gradually decreased during grain filling, while the ADP-glucose Pyrophosphorylase activity of all buckwheat was decreased firstly then increased during grain filling excluding tongliaobendixiaoli, that showed a gradually reduced pattern of ADP-glucose Pyrophosphorylase activity during grain filling.5 Effects of exogenous hormones on grain filling of common buckwheatCommon buckwheat Tongliaobendiliaoli was usedas experimental material to study the effect of exogenous hormones on grain filling process, the content of total starch, amylose and amylopectin and starch synthesis related enzyme activity at 7 days and 21 days after the grain filling. The results showed that the filling process was followed asa "S" curve. The largest values of the tmax.G,Gmax and I were detected in A2B2C3, A2B1C1 and A0B0C0, respectively The activities of starch synthase and ADP-glucose Pyrophosphorylase at 7 days after flowering were higher than than those at 21 days after flowering, while the content of total starch, amylose and amylopectin in grains were increased from 7 to 21 d after grain filling.