分根处理促进木薯氮的高效利用

Split-root Treatment Promoted Nitrogen Utilization Efficiency of Cassava

氮是农业生产中应用最多的肥料,也是植物生长最主要的限制因子。了解植物如何感知外界氮浓度变化的信号,调整自身代谢及根系形态以吸收氮素,获得较高的氮利用效率,是非常值得研究的课题。本研究采用分根系统对木薯根系两侧进行不同氮处理,并对均质和分根处理的木薯植株以及根际土的氮含量进行了测定。结果表明分根处理下的木薯在施用均质处理一半的硝酸盐条件下,株高、生物量与均质处理差异不大,但是块根发育进程更快,叶片中全氮含量更高,且分根两侧土壤中的有效氮含量更低,说明分根两侧土壤中的氮更多地吸收和转运到了木薯体内。此外,木薯可以感知系统低氮信号并促进氮吸收同化基因在分根的高氮一侧高表达,这有利于木薯在高氮一侧的氮吸收,进而促进木薯的氮高效利用。

Nitrogen is the most widely used fertilizer in agricultural production,but also the most important limiting factor for plant growth.Understanding how plants sense variable external nitrogen signals to adjust root architecture and achieve higher nitrogen utilization efficiency is a very important topic of research.Our experiment used split-root system treat cassava with heterogeneous and homogeneous nitrogen,and determined the nitrogen content of plants and rhizosphere soil.The results showed that the heterogeneous treatment,applied half of nitrogen,had no difference with homogeneous treatment in plant height and biomass,but the tuber development was speed up,and the total nitrogen content in the leaves is higher than homogeneous treatment.In addition,the available nitrogen content on the heterogeneous treatment is lower than homogeneous nitrogen treatment,indicating that more nitrogen in the soil on the heterogeneous treatment was uptook and transferred to cassava.Furthermore,cassava can sense the system low N signal and promote the expression of nitrogen uptake and assimilation genes in the high nitrogen side,which is conducive to the nitrogen absorption in the high nitrogen side of cassava,thus promoting the efficient utilization of nitrogen.