抽穗期土壤干旱对水稻根系和叶片生理特性的影响

Effects of Soil Drying at Heading Stage on Physiological Characteristics in Root and Leaf of Rice

研究目的干旱是限制水稻作物产量的主要生态因子之一,抽穗期是水稻生长对干旱胁迫比较敏感的时期,因此研究根系和叶片对抽穗期不同程度水分胁迫的生理响应具有重要的意义;方法以水稻品种丰华占为实验材料,研究了抽穗期控水时间长短对水稻根系活力、叶片水势和保护酶活性等生理特性的影响;结果抽穗期干旱胁迫后叶片水势显著下降,复水后均可回复到对照水平。干旱3,6,9d根系活力分别上升28.83%,123.30%和50.16%,而干旱12d则下降82.25%。除长期干旱处理造成保护酶活性下降外,其他不同程度土壤干旱胁迫均造成叶片和根系的超氧化物歧化酶(SOD)、过氧化物酶(POD)酶和过氧化氢酶(CAT)酶活性活性显著提高,而且干旱胁迫时间越长,保护酶活性上升越高,复水后可恢复到对照水平。研究还表明,无论干旱与否,叶片的SOD、POD和CAT活性均远远高于根部。结论水稻在抽穗期经受短期干旱能有效地进行生理调节,根系与叶片在适应干旱逆境方面具有协调统一性。

[OBJECTIVE]Water stress is one of the most important ecological factors which affect yield and quality of rice （Oryza sativa L. ）, heading stage is the most sensitive stage to water stress for rice growth. Our objective was to elucidate the physiological response of leaf and root system to drought at heading stage; [METHOD]Rice variety Feng-Hua-Zhan was chosen through pot experiment to study the effects of soil drying at heading stage on leaf water potential, root system activity, protective enzyme activity in leaf and root; [RESULTS]Leaf water potential was significantly decreased after soil drying and it could be restored to the normal level after re-irrigation. Root activity was increased by 28.83%, 123.30% and 50.16% when soil drying lasted 3 d, 6 d and 9 d at heading stage, it could restore to normal level except 9 d treatment after reirrigation, but root system activity was decreased by 82.25% when soil drying lasted 12 d. Except for the treatment with 12 days of soil drying, superoxide dismutase （SOD）, catalase （CAT）and peroxidase （POD）activity in leaf and root increased significantly after soil drying, and they could restore to normal level after reirrigation. SOD, POD and CAT activity in leaf had higher level than that in root whatever irrigation or not; [CONCLUSION]Rice plant could effectively adjust physiological equilibrium after short-term drought at heading stage, root system and leaves had the similar change trend.