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| DOI：10.13522/j.cnki.ggps.2020311 |
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| The Response of Gas Exchange Parameters of Winter Wheat Leaves to Water Stress |
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ZHANG Yushun, LU Zhenguang, ZHANG Mingzhi, DING Pengfei,WANG Hongming, YANG Haochen, QIU Xinqiang
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1. Henan Provincial Water Conservancy Research Institute/Center of Efficient Irrigation Engineering and Technology Research of Henan Province, Zhengzhou 450003, China; 2. Xuchang Experiment and Extension Station of Farmland Water Conservancy, Xuchang 461000, China
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| Abstract: |
| 【Background】Henan province is a key agricultural base in Huang-Huai-Hai plain of China, but its production is constrained by water shortage. Winter wheat is the main crop grown in this region and during its growth season the precipitation can only meet 25%~40% of its demand. As such, two-three irrigations are needed to ensure its yield. Identifying water status of the winter wheat is hence crucial to maximizing water use efficiency of the wheat in designing irrigation schedule.【Objective】The objective of this paper focuses on physiology of the wheat, investigating experimentally how gas exchange parameters of the wheat leaves respond to water stress and its consequence for yield.【Method】The experiment was conducted in lysimeters. We took the variety of Zhoumai22 as the model plant and measured in the experiment the variation in leaf gas exchange parameters, grain yield, water consumption of the wheat under water stress occurring at different growth stages.【Result】Drought occurring at any growth stage of the wheat led to a reduction in its total water consumption, especially when the drought was severe. Average reduction in the yield and water consumption over the two experimental seasons were 9.89% and 2.89% (light drought), 14.72% and 7.46% (moderate drought), 23.62% and 21.85% (severe drought), respectively. The impact of drought occurring at the seedling stage had limited effects on leaf gas exchange in the early stage but became noticeable after the jointing stage. Severe drought significantly reduced Pn, Tr and Gs, while rewetting after the jointing stage following a light drought could compensate the loss. The stomatal limit value was linearly correlated with Gs and Tr, and its value was less than 0.3. The values of WUE under different water stresses were calculated from its dependence on Pn, Tr.【Conclusion】Keeping the roots at seedling stage under a certain degree of water stress is beneficial to promoting their growth. After the jointing stage, severe water stress or long- term continuous drought could significantly impede gas exchange in the leaves and thus should be avoided. Our results showed that the leaf gas exchange parameters can be used to diagnose water stress and help design irrigation. |
| Key words: winter wheat; water stress; water use efficiency; stomatal limit; Variety of Zhoumai 22 |
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