| In order to identify nitrogen-efficient cultivars by the morphological and quantitative root traits at early seedling stage,the relationships between the nitrogen use efficiency of seedling and the morphological and quantitative root traits of 18 wheat cultivars in the Huanghuai plains were studied by solution culture method under normal nitrogen(5 mmol·L-1) and high nitrogen(45 mmol·L-1) conditions. Nitrogen use efficiency of the plant was evaluated by both dry weight and nitrogen accumulation combined with root morphological and quantitative parameters,and hence different types of nitrogen use efficiency were grouped. Under two nitrogen conditions,coefficients of variation for root dry weight,shoot dry weight,plant dry weight,root nitrogen concentration,shoot nitrogen concentration,plant nitrogen concentration,total root length,total root surface area,total root volume,root tips per plant of the tested cultivars were all more than 15%,which can be used as comprehensive evaluation indices of nitrogen use efficiency. Total root length,total root surface area,total root volume,root tip sand nitrogen accumulation per plant were significantly positively correlated. Total root length,total root surface area,total root volume,root tips per plant of cultivars with different nitrogen use efficiency ranked as high nitrogen efficiency > middle nitrogen efficiency > low nitrogen efficiency. A predictive model for nitrogen accumulation in seedling and the morphological and quantitative root traits was established,by gradual regression analysis with a fitting precision higher than 91.91%.There were significant differences in total root length,total root surface area,root tips per plant of wheat cultivars with different nitrogen use efficiency,and hence nitrogen use efficiency of different cultivars can be indicated according to the morphological and quantitative root traits at seedling stage. |
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