施氮水平对不同氮效率苎麻渗透调节的影响

Effects of Nitrogen Application on Osmotic Adjustmentof Ramie (Boehmeria nivea L.) with Different NitrogenEfficiency

苎麻是重要的天然纤维作物,也是优质的生物质资源。前期研究表明,常规农作物中苎麻氮农学效率低下(NAE=23.2%~27.8%),且普遍存在过量施氮的问题。植物渗透调节对环境胁迫积极响应并对植物抗性改进发挥重要作用,但由于复杂的植物-环境互作关系及对特定物种的深入分析,研究结论并不一致。通过改良渗透调节提高苎麻产量,该研究以氮高效基因型苎麻H2000-03和氮低效基因型苎麻册亨家麻为材料,设置5个施氮水平(N0-0 mmol/L、N6-6 mmol/L、N9-9 mmol/L、N12-12 mmol/L和N15-15 mmol/L),探讨了施氮和渗透调节在增进苎麻生长和产量中的作用。结果表明:苎麻通过渗透调节适应不同施氮水平,而渗透调节物质含量仅在特定的生长阶段表现出显著差异。两个基因型苎麻的产量、游离脯氨酸(Pro)、可溶性蛋白(SP)、可溶性糖(SS)、丙二醛(MDA)等渗透调节物质含量、氮敏感指数(NSI)和综合评价值随氮素水平提高,其变化曲线均出现明显的拐点。该研究认为,在较低的氮水平和适当的生长阶段全面提高苎麻的渗透调节能力是提高苎麻的氮农学效率的合理途径。

Ramie (Boehmeria nivea L.) is one of the most important fiber crops and biomass materials. However, previous studies showed that ramie presented a very low nitrogen agronomy efficiency (NAE, 23.2%~27.8%) in traditional farming, and the nitrogen fertilizer was applied excessively in ramie field. Plant osmotic adjustment (OA) responses to environmental stresses positively and exhibits improvements in plant tolerance. Whereas results varied due to the complexity of plant-environment interactions and lack of insights of specific species. In order to improve ramie production through osmoregulation, our current study investigated the role of nitrogen application and osmotic adjustment in improving the growth and yield in two varieties of ramie (H2000-03 and Ceheng Jiama) with contrasting nitrogen use efficiency (NUE) grown at 5 different N rates including N0, N6, N9, N12 and N15;0, 6, 9, 12 and 15 mmol/L N, respectively. The results showed that ramie adapted to different nitrogen rates through OA and significant differences of osmolyte content between varieties only presented at the particular growth stage. Obvious inflexion of yield, osmolyte content involving proline, soluble protein (SP), soluble sugar (SS) and malonaldehyde (MDA);nitrogen sensitive index (NSI) and comprehensive evaluation (D) in both varieties were observed. Our results recommended that the overall lifting of OA at a lower N level and at the proper growth stage would be a reasonable approach for improving ramie NUE.