Analysis of Dynamic Changes of Endosperm Starch Content and Related Gene Expression at Different Stages of Rice Seed Germination

Abstract

When seeds reach full maturity, they store large amounts of nutrients such as starch, which serve as the energy base for the subsequent germination process. This study took rice seeds as the research object, focusing on analyzing the changes in endosperm starch content at different germination stages and the expression of key genes involved in starch hydrolysis. Multiple technical methods were adopted, such as iodine staining microscopy, total RNA extraction, and reverse transcription-quantitative PCR (RT-qPCR), to detect and analyze the shape, quantity, and staining intensity of endosperm starch granules, and the relative expression of the OsAmy1A gene in rice seeds germinated for 1, 3, and 5 days. The results showed that during rice seed germination, the seeds presented obvious temporal developmental characteristics: no obvious germination phenomenon at 1 day, radicle protrusion at 3 days, and seedling emergence at 5 days. The endosperm starch content showed a continuous downward trend, which was consistent with the energy demand of seed development. As a key gene for starch hydrolysis, the relative expression of OsAmy1A increased gradually, with a significant increase between 3 and 5 days of germination. These two dynamic changes were closely related, which proved that the OsAmy1A gene accelerates the hydrolysis and transformation of endosperm starch by regulating the synthesis of α-amylase, thus providing the necessary energy and materials for seed germination and early seedling growth. The results of this study provide an experimental basis for further exploring the regulatory mechanism of material metabolism during rice seed germination, and also provide practical reference for optimizing rice seed storage, improving processing technology, and enhancing rice quality.