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| DOI：10.13522/j.cnki.ggps.2017.0555 |
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| Effects of Alternating Drought and Watering on Growth, Photosynthesis and Yield of Wither Wheat |
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LI Yanbin, ZHU Yanan, LI Daoxi, GAO Yang
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1.College of Water Conservancy，North China University of Water Resources and Electric Power， Zhengzhou 450000, China; 2. Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China
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| Abstract: |
| 【Objective】 The purpose of this paper is to study the effect of alternating water stress and rehydration on growth, photosynthesis and yield of winter wheat at different growth stages.【Method】 We took the variety of Aikang 58 as the model plant and examined four levels of water stress: slight water stress (60%~70% of field capacity), moderate water stress （50%~60% of field capacity）, severe water stress （40%~50% of field capacity） with each occurring at jointing, or heading or filling stages. The control （CK） was to keep the soil moisture at 70%~80% of field capacity. In each treatment, we measured the physiological and growth characteristics under different drought-watering cycles.【Result】 Moderate and severe water stress occurring at the jointing, heading and filling stage significantly reduced plant height and leaf area, especially at the jointing stage where moderate and severe water stress reduced the plant height by 18.6% and 29.0% and leaf by 18.2% and 49.5%, respectively, compared to the CK. Net photosynthetic rate and stomatal conductance were sensitive to water stress. Watering can restore the reduced net photosynthetic rate and stomatal conductance after a slight water stress, but not after a moderate or severe drought. The net photosynthetic rate and stomatal conductance were more difficult to recover after moderate or severe drought occurring at the filling stage than occurring at the jointing or heading stage. Grain filling stage was most water-demanded for photosynthesis, during which slight, moderate and severe drought reduced the stomatal conductance by 28.7%, 34.0% and 49.4%, and the net photosynthetic by 10.5%, 23.2% and 28.0%, respectively, compared to the CK. The yield under moderate and severe water stress differed significantly, and water stress during the jointing and heading period reduced not only panicle number and the number of grains per spike, but also the yield and 1000-grain weight. 【Conclusion】 A slight water stress can save water without compromising yield. The grain filling stage is the key period for wheat photosynthesis and keeping sufficient water at this stage is critical to achieve high yield. |
| Key words: wheat; drought; re-watering; photosynthesis; yield |
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