Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China.
Institute of Cotton Research of CAAS/State Key Laboratory of Cotton Biology, Anyang, Henan 455000, China.
J Plant Physiol. 2018 May-Jun;224-225:30-48. doi: 10.1016/j.jplph.2018.03.001. Epub 2018 Mar 9.
The objective of this study was to investigate the root growth compensatory effects and cotton yield under drought stress. The results indicate that the root dry weight, boll weight, and cotton yield increased in both the drought-resistant cultivar (CCRI-45) and the drought-sensitive cultivar (CCRI-60). Compensation effects were exhibited under the three-day drought stress treatment at a soil relative water content (SRWC) of 60% and 45% during the seedling stage, and flowering and boll-forming stage over two years. The yield of the drought-resistant cultivar (CCRI-45) was higher than the control, however, following the six-day 45% SRWC drought treatments, the yield of the drought-sensitive cultivar (CCRI-60) was lower than the control. The soluble sugar content, proline content, superoxide dismutase (SOD) activity, and peroxidase (POD) activity of the roots increased under drought stress and then decreased after re-watering, although the values remained higher than those of the controls for a short period. These physiological measures may represent stress reactions and thus may not indicate factors that result in compensation effects. However, catalase (CAT) activity and gibberellic acid (GA) content of the roots decreased under drought stress. After re-watering, the CAT activity and the GA content increased and were significantly higher than those of the controls under the six-day 60% SRWC and 45% SRWC drought treatments. The abscisic acid (ABA) content of the roots increased under drought stress. After re-watering, the ABA content decreased to a lower level under the three and six-day 60% SRWC and 45% SRWC drought treatments than in the controls. According to an analysis of various indicators, the interaction between ABA and GA signals may play an important role in root growth compensatory effects. In summary, the results demonstrate that moderate drought stress is beneficial to root growth and yield. This conclusion is of great significance to improving our understanding of the maximum utilization of limited water resources.
本研究旨在探究干旱胁迫下棉花根系生长补偿效应与产量变化。结果表明，在土壤相对含水量（SRWC）分别为 60%和 45%、持续 3 天的苗期干旱胁迫和两年中开花结铃期持续 2 天的干旱胁迫下，抗旱品种（CCRI-45）和感旱品种（CCRI-60）的根系干重、铃重和产量均有所增加。在抗旱品种（CCRI-45）中，产量高于对照，但在 6 天 45%SRWC 干旱胁迫后，感旱品种（CCRI-60）的产量低于对照。干旱胁迫下根系的可溶性糖、脯氨酸、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性升高，复水后下降，但仍短时间高于对照。这些生理措施可能是一种应激反应，不一定是导致补偿效应的因素。但干旱胁迫下根系的过氧化氢酶（CAT）活性和赤霉素（GA）含量降低，复水后 CAT 活性和 GA 含量升高，在 6 天 60%SRWC 和 45%SRWC 干旱胁迫下显著高于对照。干旱胁迫下根系的脱落酸（ABA）含量增加，复水后 ABA 含量在 3 天和 6 天 60%SRWC 和 45%SRWC 干旱胁迫下均低于对照。综合各项指标分析，ABA 和 GA 信号的相互作用可能在根系生长补偿效应中起重要作用。综上所述，适度干旱胁迫有利于根系生长和产量形成。该结论对充分利用有限水资源具有重要意义。
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