Adequate supply of potassium improves plant water‐use efficiency but not leaf water‐use efficiency of spring wheat |
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| Authors: | Bálint Jákli Merle Tränkner Mehmet Senbayram Klaus Dittert |
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| Affiliation: | 1. Institute of Applied Plant Nutrition, University of G?ttingen, Carl‐Sprengel‐Weg 1, 37075 G?ttingen, Germany;2. Present Address: Department of Soil Science and Plant Nutrition, Harran University, 63200 ?anl?urfa, Turkey;3. Department of Crop Science, Section of Plant Nutrition & Crop Physiology, University of G?ttingen, Carl‐Sprengel‐Weg 1, 37075 G?ttingen Germany |
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| Abstract: | Enhancing crop water‐use efficiency (WUE) is a major research objective in water‐scarce agroecosystems. Potassium (K) enhances WUE and plays a crucial role in mitigating plant stress. Here, effects of K supply and PEG‐induced water deficit on WUE of spring wheat (Triticum aestivum L. var. Sonett), grown in nutrient solution, were studied. Plants were treated with three levels of K supply (0.1, 1, 4 mM K+) and two levels of PEG (0, 25%). WUE was determined at leaf level (WUEL), at whole‐plant level (WUEP), and via carbon isotope ratio (δ13C). Effects of assimilation and stomatal conductance on WUEL were evaluated and compared with effects of biomass production and whole‐plant transpiration (EP) on WUEP. Adequate K supply enhanced WUEP up to 30% and by additional 20% under PEG stress, but had no effect on WUEL. EP was lower with adequate K supply, but this effect may be attributed to canopy microclimate. Shoot δ13C responded linearly to time‐integrated WUEL in adequately supplied plants, but not in K‐deficient plants, indicating negative effects of K deficiency on mesophyll CO2 diffusion. It is concluded that leaf‐scale evaluations of WUE are not reliable in predicting whole‐plant WUE of crops such as spring wheat suffering K deficiency. |
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| Keywords: | 13C discrimination PEG potassium nutrition water deficit water use efficiency Triticum aestivum |
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