Magnesium fertilizer application increases peanut growth and pod yield under reduced nitrogen application in southern China

This study investigated the effect of magnesium application on peanut growth and yield under two nitrogen(N)application rates in acidic soil in southern China.The chlorophyll content,net photosynthetic rate and dry matter accumulation of the N-sensitive cultivar decreased under reduced N treatments,whereas no effect was observed on the relevant indicators in the N-insensitive variety GH1026.Mg application increased the net photosynthetic rate by increasing the expression of genes involved in chlorophyll synthesis and Rubisco activity in the leaves during the pegging stage under 50%N treatment,while no effect on the net photosynthetic rate was observed under the 100%N treatment.The rate of dry matter accumulation at the early growth stage,total dry matter accumulation and pod yield at harvest increased after Mg application under 50%N treatment by increasing the transportation of assimilates from stems and leaves to pods in both peanut varieties,whereas no effect was found under 100%N treatment.Moreover,Mg application increased the NUE under 50%N treatment.No improvement of NUE in either peanut variety was found under 100%N treatment,while Mg application under the 50%N treatment can obtain a higher economic benefit than the 100%N treatment.In acidic soil,application of 307.5 kg ha^(-1)of Mg sulfate fertilizer under 50%reduced nitrogen application is a suitable fertilizer management measure for improving carbon assimilation,NUE and achieve high peanut yields in southern China.

氮素调控花生共生结瘤的机制研究进展

氮是花生生长发育所需的大量元素,共生结瘤固氮是花生获取氮素的主要方式之一。花生共生结瘤固氮涉及复杂的调控机理,揭示氮素对根瘤固氮的调控机制对发挥生物固氮潜力具有重要意义。本文系统总结了花生根瘤形成的“裂隙侵染”机制、花生共生结瘤和数量调控的机制以及氮素影响花生结瘤的调控机制。目前,氮素影响慢生根瘤菌与花生互作进而调控结瘤的分子机理尚不清楚,因此未来的研究重点应该集中在氮素影响花生慢生根瘤菌与花生的信号交流、根瘤数调节和营养交换机制等方面,为提高花生结瘤固氮效率和产量、减少化学氮肥施用提供理论基础。