Differences in Starch Chain Length Distribution and Structure Characteristics of Early-Indica Rice Under Different Temperature Treatments During Grain Filling

摘要

Effects of temperature during grain-filling on chain length distribution and structure characteristics of 4 early-season indica rice cultivars were investigated under the environment-controlled conditions. The plants at flowering stage were subjected to two temperature treatments until maturity (the mean dairy air temperature, 22 and 32℃ for optimum temperature treatment and high temperature treatment, respectively). The result showed that high temperature during grain-filling significantly decreased the long B-chain content and increased the intermediate B-chain content. But the effect of high temperature on other starch chains appeared to be cultivar-dependant. The crystalline characteristics of rice starch were also affected by temperature during grain-filling. The intensity at 18° 2 θ of X-ray diffraction pattern of rice samples under high temperature was higher than those under optimum temperature, though all rice starches performed A-crystalline type. Moreover, the intensity at 18° 2 θ was positive correlation with intermediate B-chain content and negative correlation with long B-chain content.