籼型和粳型水稻响应孕穗期干旱胁迫的生理特性差异

Difference of physiological characteristics between Indica rice and Japonica rice in response to drought stress at booting stage

【目的】系统比较分析籼稻和粳稻响应孕穗期干旱胁迫的生理特性差异,以期为后续解析籼、粳型水稻抗旱能力差异的生理机制打下前期基础。【方法】以具有不同耐旱能力的籼稻珍汕97B(ZS97B)和粳稻日本晴(NP)为材料,以正常浇水保持土壤湿润为对照,孕穗期停止浇水,干旱胁迫10 d后分别检测不同处理的水稻气孔密度、气孔开放度、光合指标、蒸腾指标、水分生理相关指标、抗氧化酶活性及丙二醛含量等;干旱处理13 d后复水,统计复水10 d后水稻存活率,比较分析孕穗期ZS97B和NP对干旱胁迫的适应性。【结果】孕穗期停止浇水10 d后,ZS97B的存活率为90.3%,极显著高于NP(77.8%)(P<0.01,下同);干旱胁迫对2种水稻的气孔密度和气孔运动均无显著影响(P>0.05),但ZS97B的气孔密度在处理前后显著(P<0.05,下同)或极显著高于NP;尽管ZS97B的叶卷曲度更大,但其净光合速率并没有受到更严重影响,ZS97B的净光合速率下降31.2%,而NP下降62.9%;此外,干旱胁迫下NP的叶片失水速率上升,其叶片功能损伤更严重;ZS97B在干旱胁迫后叶片POD活性极显著上升至32.46 U/(g·min),对干旱胁迫的响应更快,而NP的MDA含量也在干旱胁迫后显著上升至1.55μmol/g,表明叶片细胞膜损伤程度更严重。【结论】与粳稻品种NP相比,籼稻品种ZS97B更高的气孔密度缓解了孕穗期干旱胁迫下其光合速率的降低;同时,ZS97B通过增加叶卷曲度而降低叶片蒸腾速率;此外,ZS97B抗氧化酶系统的迅速响应也能有效清除活性氧,减少细胞膜损伤,对孕穗期干旱胁迫的适应性更强。

【Objective】This study systematically compared and analyzed the physiological characteristics of Indica rice and Japonica rice in response to drought stress at the booting stage,hoping to lay the foundation for the subsequent analysis of the physiological mechanism of the drought resistance difference between Indica rice and japonica rice.【Method】Indica rice Zhenshan 97 B(ZS97 B)and Japonica rice Nipponbare(NP)with different drought tolerance capabilities were used as materials,normal watering and maintaining soil moist as control,stopped watering at booting stage,the stomata density and stomata opening degree,photosynthetic indexes,transpiration indexes and water physiological related indexes,antioxidant enzyme activity and malondialdehyde content were measured after 10 d of drought treatment. Rewatering after13 d of drought treatment,the survival rate of rice after 10 d of rewatering was calculated statistically,comparison and analysis of the adaptability of ZS97 B and NP to drought stress at the booting stage were conducted.【Result】After 10 d of stopping watering at the booting stage,the survival rate of ZS97 B was 90.3%,which was extremely significantly higher than that of NP(77.8%)(P<0.01,the same below). The stomata density and stomata movement of two rice cultivars had no significant effect compared to the control(P>0.05),but the stomata density of ZS97 B was significantly(P<0.05,the same below)or extremely significantly higher than that of NP before and after the treatment. Although the leaf rolling index of ZS97 B was higher than NP,its photosynthetic rate was not severely affected. The photosynthetic rate of ZS97 B decreased by 31.2%,while NP decreased by 62.9%. In addition,the leaf water loss rate of NP increased significantly under drought stress,and its leaf function damage was more serious than ZS97 B. POD activity in leaves of ZS98 B was extremely significantly increased to 32.46 U/(g·min)after drought stress,it was speculated that ZS97 B responded more quickly to drought stress than NP;while the MDA content of NP also significantly increased to 1.55 μmol/g after drought stress,indicating that the damage of cell membrane was more severe than ZS97 B.【Conclusion】Compared with the Japonica rice variety NP,the higher stomatal density of the Indica rice variety ZS97 B alleviates the decrease in photosynthetic rate under drought stress at booting stage. At the same time,ZS97 B reduces leaf transpiration rate by increasing leaf rolling index. In addition,the rapid response of ZS97 B antioxidant enzyme system can also effectively eliminate active oxygen reduces cell membrane damage,and is more adaptable to drought stress at the booting stage.