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| Root water and nitrogen uptake are key processes for plant growth and soil water and nitrogen transport in the soil-plant system. Enormous effort has been made to set up the rational root-water-uptake (RWU) and root-nitrogen-uptake (RNU) models on the basis of root length to simulate soil water and nitrogen dynamics. However, the diversities of root uptake activity among different roots or different parts of a root, and the effect of soil nitrogen level on RWU were ignored. In this study, two greenhouse experiments with winter wheat seedlings cultured in nutrient solution (Exp. 1) and sand soil columns (Exp. 2) were conducted to investigate the relationship between root water/nitrogen uptake activity and root length, root nitrogen mass (RNM) of winter wheat under optimal water condition. Results showed that the potential RWU and RNU coefficients (per unit root length) changed sensitively with root age and soil nitrogen level. Nevertheless, when RNM was taken into consideration, RWU and RNU were found to be linearly correlated with RNM, and the potential RWU coefficient per unit RNM was almost a constant for both the whole root zone and different soil layers, independent of root age and soil nitrogen level but dependent linearly on the free water surface evaporation rate. The interrelations between RWU, RNU and RNM of winter wheat under optimal water condition would be helpful to set up rational RWU and RNU models for simulating soil water and nitrogen movement in the soil-wheat system. |
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| Keywords: root-water-uptake, root-nitrogen-uptake, root nitrogen mass, winter wheat |
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