Liu Jiahuan, Zhang Kangkang, Bi Junguo, Yu Xinqiao, Luo Lijun, Hu Liyong
Ministry of Agriculture and Rural Affairs (MARA) Key Laboratory of Crop Ecophysiology Farming System in the Middle Reaches of the Yangtze River, College of Plant Science Technology, Huazhong Agricultural University, Wuhan, China.
Shanghai Agrobiological Gene Center, Shanghai, China.
Front Plant Sci. 2023 May 8;14:1171331. doi: 10.3389/fpls.2023.1171331. eCollection 2023.
The application of nitrogen fertilizer within a normal range has been found to increase the leaf nitrogen content and photosynthetic rate of canola plants ( L.). Despite numerous studies on the separate effects of CO diffusion limitation and nitrogen allocation trade-off on photosynthetic rate, few have examined both these factors in relation to the photosynthetic rate of canola. In this study, two genotypes of canola with varying leaf nitrogen content were analyzed to determine the impact of nitrogen supply on leaf photosynthesis, mesophyll conductance, and nitrogen partitioning. The results showed that the CO assimilation rate (), mesophyll conductance ( ), and photosynthetic nitrogen content ( ) increased with an increase in nitrogen supply in both genotypes. The relationship between nitrogen content and followed a linear-plateau regression, while had linear relationships with both photosynthetic nitrogen content and , indicating that the key to enhancing is increasing the distribution of leaf nitrogen into the photosynthetic apparatus and , rather than just increasing nitrogen content. Under high nitrogen treatment, the genotype (QZ) with high nitrogen content had 50.7% more nitrogen than the other genotype (ZY21), but had similar , which was primarily due to ZY21's higher photosynthetic nitrogen distribution ratio and stomatal conductance ( ). On the other hand, QZ showed a higher than ZY21 under low nitrogen treatment as QZ had higher and compared to ZY21. Our results indicate that, in selecting high PNUE rapeseed varieties, it is important to consider the higher photosynthetic nitrogen distribution ratio and CO diffusion conductance.
研究发现，在正常范围内施用氮肥可提高油菜（L.）植株的叶片氮含量和光合速率。尽管已有众多研究分别探讨了CO扩散限制和氮分配权衡对光合速率的影响，但很少有研究同时考察这两个因素与油菜光合速率的关系。在本研究中，对两种叶片氮含量不同的油菜基因型进行了分析，以确定氮供应对叶片光合作用、叶肉导度和氮分配的影响。结果表明，两种基因型的CO同化速率（）、叶肉导度（）和光合氮含量（）均随氮供应的增加而增加。氮含量与之间的关系呈线性-平台回归，而与光合氮含量和均呈线性关系，这表明提高的关键在于增加叶片氮向光合机构和的分配，而不仅仅是增加氮含量。在高氮处理下，高氮含量的基因型（QZ）比另一个基因型（ZY21）的氮含量多50.7%，但其相似，这主要是由于ZY21具有更高的光合氮分配比例和气孔导度（）。另一方面，在低氮处理下，QZ的比ZY21高，因为与ZY21相比，QZ具有更高的和。我们的结果表明，在选择高光合氮利用效率的油菜品种时，考虑较高的光合氮分配比例和CO扩散导度很重要。
