不同氮素利用效率小麦苗期的根系形态数量性状分析

为在苗期可通过根系形态数量性状对氮高效小麦品种进行鉴别,利用营养液培养法,在正常氮(5mmol·L~(-1))和高氮(45mmol·L~(-1))处理下,研究了黄淮平原区18个主栽小麦品种苗期氮素利用效率与根系形态数量性状的关系;通过干物重和氮积累量与根系形态指标相结合的方式对供试小麦品种植株氮效率进行了综合评价,并划分不同氮效率类型。结果发现,在两种氮处理下,供试小麦品种的根干重、茎叶干重、单株干重、根氮含量、茎叶氮含量、单株氮含量、单株总根长、根总表面积、根总体积、根尖数的变异系数均大于15%,可作为氮效率评价指标。小麦的单株总根长、根总表面积、根总体积、根尖数与植株氮积累量呈显著正相关,可以作为育种早期筛选高氮效率材料的指标。不同氮效率类型的单株总根长、根总表面积、根总体积、根尖数均表现为氮高效型氮中效型氮低效型。通过逐步回归分析,建立了小麦幼苗植株氮积累量和根系形态数量性状的预测模型,拟合精度在91.91%以上。小麦不同氮效率类型间的单株总根长、根总表面积、单株根尖数的差异均达显著水平,生产上可根据小麦苗期根系的主要形态数量性状判断其氮效率高低。

Analysis on Morphological and Quantitative Seedling Root Traits of Cultivars with Different Nitrogen Use Efficiency in Wheat(Triticum aestivum L.)

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.