Responses of photosynthesis, dry mass and carbon isotope discrimination in winter wheat to different irrigation depths
2018
Zheng, L. J. | Ma, J. J. | Sun, X. H. | Guo, X. H. | Jiang, J. | Ren, R. | Zhang, X.-L.
In order to test the effects of irrigation depth on winter wheat photosynthesis, four treatments were applied in a field experiment using PVC growth tubes (identical amounts of water were applied on the land surface, and at 60, 75, and 90% of the depth for the winter wheat root distribution, denoted as D0, D60, D75, and D90, respectively). Compared to the surface irrigation treatment D0, the leaf area index, chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance, and intercellular CO₂ concentration increased with irrigation depths. The values of these indicators obtained by the underground irrigation treatment D75 were higher than those of D60 and D90, and thus D75 was found to be the optimum irrigation depth. Furthermore, a positive but not significant correlation (r = 0.62) between carbon isotope discrimination (Δ¹³C) and grain yield was found. This study improves our understanding of the mechanism of underground water distribution control with depth, and the efficiency of water-saving irrigation for winter wheat.
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