不同施肥处理对盆栽不同品种茶树根系生理活性及CsAMT2s基因表达的影响

Effects of different fertilization treatments on the physiological activities of roots and the expression of CsAMT2s in potted tea cuttings of different varieties

NH_(4)^(+)作为植物吸收氮素的低耗能方式,其吸收利用效率直接影响植物的生长发育,铵转运蛋白(ammonium transporter,AMT)具有介导植物NH_(4)^(+)跨膜转运的功能,在其吸收和代谢过程中发挥着重要作用.茶树具有偏好吸收NH_(4)^(+)-N特性,合理施肥对于茶树铵转运蛋白发挥转运NH_(4)^(+)的功能具有重要意义.以等氮量“0.25 g/kg”土进行不同施肥处理,选择不同氮吸收型的福鼎大白茶(氮高效型)、黄棪(高氮高效型)及毛蟹(低氮高效型)盆栽苗为供试材料.将无施肥处理作为对照,进行纯化肥处理、纯有机肥处理以及化肥有机肥配施处理,对茶树根系活力水平、根系总氮含量、根系NH_(4)^(+)-N含量、土壤理化性质以及CsAMT2s基因表达量进行检测,并对具有高亲和性CsAMT2.2和CsAMT2.3蛋白进行亚细胞定位试验.结果显示,有机肥与化肥配施处理有利于茶树盆栽苗根系的生长发育以及土壤理化性质的改善;根系CsAMT2.2和CsAMT2.3转录水平显著高于其他CsAMT2s基因,并且在纯有机肥处理与有机肥化肥配施处理下表现出较高表达水平;茶树根系活力、根系含氮量及根系NH_(4)^(+)-N含量与CsAMT2s基因存在不同程度正相关关系;亚细胞定位结果表明,CsAMT2.2和CsAMT2.3蛋白均定位于细胞质膜上.本研究表明CsAMT2.2和CsAMT2.3具有转运NH_(4+)的能力,不同施肥处理中有机肥与化肥配施最利于茶树CsAMT2s基因的表达及铵态氮的吸收代谢.

As a low-energy-consuming method of nitrogen uptake by plants,the absorption and utilization efficiency of NH_(4)^(+)directly affect plant growth and development.The ammonium transporter(AMT)mediates the transmembrane transport of NH_(4)^(+)in plants and plays an important role in its absorption and metabolism.Tea plants prefer NH_(4)^(+)-N uptake;therefore,reasonable fertilization is important for the ammonium transporter protein to transport NH_(4)^(+).Different fertilization treatments were applied to potted plants with 0.25 g/kg of nitrogen in the soil per pot:Fuding Dabaicha(nitrogen high efficiency),Huang Dan(high nitrogen,high efficiency),and Mao Xie(low nitrogen,high efficiency)were used as test materials.The no-fertilizer treatment group was used as the control,and the potted tea plants were divided into chemical,organic,and combined chemical and organic fertilizer treatment groups.The relevant detection indices included root vitality,root nitrogen content,root NH_(4)^(+)-N content,soil physical and chemical properties,and CsAMT2s gene expression.Subcellular localization experiments were performed with high-affinity CsAMT2.2 and CsAMT2.3,and the combined chemical and organic fertilizer treatment group showed the best effect.CsAMT2.2 and CsAMT2.3 could transport NH_(4+)and were highly expressed specifically in the roots.Both CsAMT2.2 and CsAMT2.3 were localized to the plasma membrane.CsAMT2.2 and CsAMT2.3 could transport NH_(4)^(+).Organic fertilizer with chemical fertilizer was the most conducive for the expression of CsAMT2s genes and the absorption of ammonium nitrogen in tea plants.The results provide a scientific and effective reference for guiding fertilization and improving the utilization rate of ammonium-nitrogen in tea plants.At the molecular level,laying a theoretical foundation for high-quality tea is necessary.