麻育秧膜对机插水稻秧苗根区氧供应及根系呼吸代谢的影响

在育秧平盘底面垫铺麻育秧膜可显著促进机插水稻秧苗根系生长发育，提高秧苗素质，其机理尚不明确。前期研究表明麻育秧膜秧苗根系特征与增氧栽培水稻根系具有高度一致性，考虑到三叶期前水稻秧苗尚未形成完善的通气组织，易处于缺氧状态，我们推测麻育秧膜增加了根表皮细胞与空气的直接接触，提高了根系摄氧，进而促进了秧苗特别是三叶期前秧苗根系呼吸代谢。本项目拟从根区氧供应的角度，探索麻育秧膜在水稻机插育秧中的作用机理，并进一步探索根际增氧对水稻秧苗的影响及其与叶龄的关系。包括：通过直接测量和间接观测分析秧盘中氧浓度时空分布规律，研究麻育秧膜对秧苗根区氧供应的影响；通过正向和逆向分析麻育秧膜对秧苗根系呼吸代谢的影响，明确氧供应在其中的角色；通过主动通气在育秧硬盘中创造不同氧浓度环境进行育秧，结合通气水培育秧，研究根系呼吸代谢对根区氧供应的响应及其与叶龄的关系。项目实施可丰富水稻机插育秧理论，完善水稻机插育秧技术。

Matting a bast fiber seedling film on the bottom surface of seedling tray significantly promotes rice seedling root growth and improves its quality, however, the mechanism is not clear. Previous studies showed a highly consistency in root characteristics between the rice seedlings raised by bast fiber seedling film and by oxygen-enriched culture. Considering that the rice seedling before three-leaf stage is susceptible to hypoxia as a result of lack of mature aerenchyma, we speculate that bast fiber seedling film could increase root oxygen intake by increasing direct contact area of root epidermal cell with air, consequently promote root respiratory metabolism of rice seedling, especially rice seedling before three-leaf stage. This project aims to explore the mechanism from the perspective of oxygen supply in root zone, and further to explore the effect of rhizosphere aeration on rice seedling and its relationship with leaf age. The main content includes: exploring effects of bast fiber seedling film on oxygen supply in root zone through investigating the spatial and temporal distribution of oxygen concentration in seedling tray by direct measurement and indirect observation; exploring effects of bast fiber seedling film on root respiratory metabolism of rice seedling through forward and backward analysis, with a clear definition to the role of oxygen supply; exploring response of root respiratory metabolism to oxygen supply in root zone and its relationship with leaf age through two ways: raising rice seedling in seedling strays of different oxygen environment by aeration under their bottom, and raising rice seedling in aerated culture solution. This project will provide theoretical basis for improving raising technology of machine-transplanted rice seedling.