Yu-Tao Huang, Wei Wu, Tiyuan Zhao
Sep 27, 2020
Journal of the science of food and agriculture
BACKGOUND Rice is an important food crop in China. Seed drying is an important link in the production of rice seeds. However, the regulatory mechanism of drying temperature on seed vigor of rice seeds with high initial moisture content (IMC) has not been examined. RESULTS This study presents hot-air drying of rice seeds with high IMC (>30%) to assess the effects of drying temperature (35°C, 41°C, and 47°C) on drying performance and seed vigor in terms of germination capacity. The results showed a significantly positive correlation between the drying rate, seed temperature, and drying temperature. High temperature drying tends to cause a large accumulation of reactive oxygen species (ROS) and increase the activities of antioxidant enzymes in rice seeds. Besides, high temperature drying significantly increased abscisic acid (ABA) content and decreased gibberellin (GA) content through the regulation of the activities of metabolism related-enzymes. Moreover, changes in GA and ABA metabolism during early seed germination might be an important reason for the decrease in seed vigor by high temperature drying. High temperature drying also significantly inhibited the activity of α-amylase during early seed germination. CONCLUSION A drying temperature of 35°C was safe for rice seeds with high IMC, whereas higher drying temperatures (41°C and 47°C) remarkably reduced rice seed vigor. The metabolism of reactive oxygen species (ROS), antioxidant enzymes, GA, ABA, and α-amylase might be closely involved in the regulation of drying temperature on the seed vigor of rice seeds with high IMC. The results of this study, therefore, provide a theoretical basis and technical guidance for mechanical drying of rice seeds. This article is protected by copyright. All rights reserved.