苏打盐碱区主推水稻品种根系形态及生理机制研究

Saline-sodic stress is one of the major obstacle factors affecting the rice production in western Jilin Province. The roots play critical roles in the formation of crop yield and adaptation to the environmental changes. It is necessary to study root morphology and physiological mechanisms of dominant rice varieties in western Jilin Province. On the basis of our preliminary studies, by using the 13 rice varieties, we will analyze the root growth dynamics in the seeding and major growth stages of the different varieties through agar culture, root-box system and in situ field experiment. Determine the key parameters of root architecture which is associated with the yield. We will further analyze the K +, Na + and H + ion flow dynamics on the different sites of rice seedling apex using scanning ion-selective microelectrode technique, investigate the primary response mechanism from the organizational levels under saline-sodic stress. Charactering spatiotemporal dynamics of the root bleeding sap and its ion composition, phytohormones contents, nutrient absorption, enzyme activity whereby revealing the physiological basis of root morphological adaptation mechanism to saline-sodic stress in different rice varieties. In addition, we will conduct quantitative analyses of the contribution of root growth plasticity changes and physiological function to rice yield under saline-sodic stress. Reveal the rice root morphological and physiological mechanisms of dominant rice varieties in saline-sodic area. Our study would provide theoretical and practical basis for deter-mining the potential of rice yield, root morphology improvement and yield-increasing in saline-sodic lands.

苏打盐碱胁迫是影响吉林省西部水稻产量的主要障碍因子之一，而根系对水稻产量形成及环境适应具有重要作用。因此，研究吉林省西部盐碱稻区主推水稻品种根系形态及生理机制十分必要。本项目拟在前期研究基础上，通过琼脂培养、根箱法及田间原位试验，以吉林省西部13个主推水稻品种为对象，明确水稻苗期及主要生育期根系建成动态，确定与产量相关的根构型关键参数；采用扫描离子选择微电极技术精确监测苏打盐碱胁迫对水稻根尖不同位点的K+、Na+和H+离子流动态，从组织水平探讨其对苏打盐碱胁迫的原初响应机制；阐明主要生育期水稻根系伤流液、营养吸收、保护酶活性和内源激素含量对根构型适应性反应的生理学基础，确定与产量相关的关键生育期及根系功能指标并定量分析其对产量的贡献，揭示苏打盐碱区主推水稻品种根系形态及生理机制。本项目对定向挖掘苏打盐碱地区水稻增产潜力，促进水稻根系性状改良及水稻增产具有重要的理论和实际意义。

苏打盐碱胁迫是影响吉林省西部水稻产量的主要障碍因子之一，而根系对水稻产量形成及环境适应具有重要作用。因此，研究吉林省西部盐碱稻区主推水稻品种根系形态及生理机制十分必要。本项目通过大田原位和盆栽实验，取得如下进展：（1）证明苏打盐碱地改良主要改善了水稻根系生长，减少了表层根系的生长，增加深层根系生长，而且根系活力增加；（2）揭示苏打盐碱胁迫下水稻根系剖面分布特征。即盐碱胁迫显著抑制水稻0～5cm根系总根长、根体积、根系表面积等；（3）明确苏打盐碱区水稻根系伤流液日变化规律，确定水稻根系伤流液的最佳取样时间；（4）苏打盐碱胁迫下主要生育期水稻根系伤流液动态呈单峰曲线，分蘖期与拔节期伤流液逐渐升高，齐穗期达到峰值，随着籽粒灌浆稻株衰老，根系伤流量逐渐降低；（5）揭示苏打盐碱胁迫下水稻根系生理特征，即轻度盐碱胁迫可以促进水稻根系伤流液分泌，但重度盐碱胁迫显著抑制水稻根系活力；（6）建立水稻根系特征快速推断方法，可以根据地上部生长性状推知根系的生长，水稻根系总根长、总表面积、总根体积与平均直径均与伤流液量、茎周长和穗数呈极显著正相关，总表面积和平均直径与绿叶数呈显著或极显著正相关；（7）水稻产量与返青期和分蘖期根角度呈极显著正相关。对定向挖掘苏打盐碱地区水稻增产潜力，促进水稻根系性状改良及水稻增产具有重要的理论和实际意义。