干湿交替灌溉对抗旱性不同水稻品种产量的影响及其生理原因分析

【目的】旨在阐明全生育期干湿交替灌溉对抗旱性不同水稻品种产量的影响。【方法】以抗旱性差异显著的4个水稻品种(籼稻扬稻6号和两优培九,粳稻旱优8号和镇稻88)为材料,以常规水层灌溉(CI)为对照,在盆栽条件下研究了轻干湿交替灌溉(WMD)和重干湿交替灌溉(WSD)对水稻产量、根系、叶片及籽粒部分生理特性的影响。【结果】与CI相比,WMD处理下抗旱性较强品种扬稻6号和旱优8号产量分别提高6.90%和7.45%,抗旱性较弱品种两优培九和镇稻88产量分别降低7.28%和8.10%。WSD处理下,4个水稻品种的产量均显著下降,抗旱性较弱的品种产量降幅远高于抗旱性较强的水稻品种。WMD处理下,扬稻6号和旱优8号复水后根系氧化力、根系与叶片细胞分裂素(玉米素+玉米素核苷)含量、叶片光合速率和籽粒中蔗糖-淀粉代谢途径关键酶的活性均较CI有不同程度提高,而两优培九和镇稻88上述指标则与CI持平或有不同程度降低。WSD处理下,4个品种上述指标均较CI不同程度降低。【结论】轻干湿交替灌溉条件下,根系活性强、叶片细胞分裂素含量和光合速率高、籽粒中蔗糖-淀粉代谢途径关键酶活性强是抗旱性较强水稻品种的基本生理特征。

Effects of Alternate Wetting and Drying Irrigation on Grain Yield in Rice Cultivars with Different Drought Resistance and Its Physiological Mechanism

【Objective】We aim to reveal the effects of alternate wetting and irrigation during whole growth period on grain yield in rice cultivars with different drought resistance and its physiological mechanisms.【Method】With four rice cultivars differed in drought resistance, Yangdao 6 and Liangyoupeijiu (indica), Hanyou 8 and Zhendao 88 (japonica), as materials, three water management regimes, i.e. CI (conventional irrigation), WMD (alternate wetting and moderate drying irrigation) and WSD (alternate wetting and severe drying irrigation) during the whole growing season were conducted to investigate their effects on grain yield in a pot experiment.【Result】Compared with CI, WMD significantly increased the grain yields of Yangdao 6 and Hanyou 8 with higher drought resistance by 6.9% and 7.5%, and decreased those of Liangyoupeijiu and Zhendao 88 with lower drought resistance by 7.28% and 8.10%, respectively. Under WSD, the grain yields of four cultivars all decreased significantly, but the yield declines in Liangyoupeijiu and Zhendao 88 were much higher than those in Yangdao 6 and Hanyou 8. Under WMD, root oxidation activity, cytokinin (zeatin + zeatin riboside) content in roots and leaves, leaf photosynthetic rate and water potential, activities of enzymes involved in sucrose-to-starch conversion in grains were all significantly increased in Yangdao 6 and Hanyou 8 after re-watering and they were all nearly the same or decreased in Liangyoupeijiu and Zhendao 88. Under WSD, these indices were all decreased in four rice cultivars. 【Conclusion】 Stronger root oxidation activity, higher cytokinin (zeatin + zeatin riboside) content in roots and leaves, greater photosynthetic rate and water potential of leaves and activities of enzymes involved in sucrose-to-starch conversion in grains after re-watering were the basic physiological characteristics in rice cultivars with strong drought resistance under WMD.