Physiological basis of the regulation of seedling emergence of rice plant

对水稻稳定直播所需的淹水出苗相关性状进行了研究。利用北方杂交和原位杂交技术，证实Ramy 3D基因编码的淀粉酶H亚型是淹水条件下淀粉分解的最主要限制性酶。此外，还研究了乙醇脱氢酶在幼苗出苗调控中的作用。然而，ADH的作用并不总是平行的种子发芽在淹水条件下，其他限制步骤的参与。膨胀素是水稻幼苗在淹水条件下萌发所必需的胚芽鞘伸长的调控因子。膨胀素的两种异构体被认为是淹水条件下胚芽鞘长度调节的可能因子。从而阐明了至少有3个主要限制步骤参与了淹水条件下水稻出苗的调控过程。

Traits related with the seedling emergence under flooded condition which is required for the stabilized direct seeding of rice were studied. Isoform H of Amylase which is encoded with Ramy 3D gene was identified as one of the most limiting step for the decomposition of starch under flooded condition both by northern blotting and by in situ hybridization methods. Besides, the involvement of alchohol dehydrogenase in the regulation of seedling emergence were examined. However, the role of ADH was not always in parallel with the seeding emergence under flooded condition and the participation of other limiting steps was suggested. As the possible factors for the regulation of coleoptile elongation which is indispensable for the seedling emergence under flooded condition, the role of expansin was studied. Two isoforms of expansin was identified as the possible factors for the regulation of coleoptile length under flooded condition. Thus the participation of at least 3 major limiting steps was elucidated in the regulation process of seedling emergence of rice under flooded condition.