甘蓝型油菜氮素高效吸收的植株形态与生理特性研究

为阐明甘蓝型油菜氮素高效吸收的形态和生理机制,利用6个氮素效率差异显著的甘蓝型油菜为供试材料,分析低氮条件下甘蓝型油菜抽薹期地上部和根系形态、叶片和根系生理特性的基因型差异及这些指标与高效氮素吸收的关系。结果表明,3个氮高效基因型在表型性状（株高、叶片数、最大叶长×宽、地上部干重、茎基粗、根长、根表面积、根体积、根平均直径和根干重）、生理（叶片可溶性糖含量、游离氨基酸总量、根系吸收总面积、活跃吸收面积、游离氨基酸总量和根系活力）和光合方面（净光合速率、气孔导度、胞间CO₂浓度、蒸腾速率和氮素光合效率）均高于3个氮低效基因型。甘蓝型油菜抽薹期根平均直径、最大叶长×宽、蒸腾速率和根系硝酸还原酶共同决定了氮素吸收效率的92.10%。

Studies on Plant Morphological and Physiological Characteristics of High Nitrogen Absorption in Brassica napus L.

In order to clarify the morphological and physiological mechanism of rapeseed (Brassica napus L.) with high nitrogen (N) absorption, six varieties with significantly different nitrogen efficiency were used as test materials, the genotype difference of shoot and root morphology, and characteristics of leaves and roots at bolting stage under the condition of low N application, as well as the relationships between these indexes and high-efficient absorption of nitrogen were analyzed. The results showed that the phenotypic traits (plant height, number of green leaves, length × width of maximum leaf, shoot dry weight, basal stem diameter, root length, root surface area, root volume, root diameter and root dry weight), physiological indexes (soluble sugar content and total free amino acid content of leaves, total absorption area, active absorption area, total free amino acid content of roots and root activity) and photosynthetic characteristics (net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate and nitrogen photosynthetic efficiency) of the three genotypes with high N nutrient efficiency were higher than those of the three genotypes with low N nutrient efficiency. Root mean diameter, length × width of maximum leaf, transpiration rate and root nitrate reductase were jointly determined 92.10% of nitrogen absorption efficience at bolting stage.