高产优质毛白杨良种施肥响应特性解析

Analysis of the fertilization response characteristics of improved variety for high yield and high quality Populus tomentosa

【目的】探寻林木最佳栽培方法是切实提高森林生产力的重要举措。由于毛白杨是杂种起源,其种内无性系间施肥响应特性差异显著。为保证人工林建设的速生丰产特性,同时减轻环境保护压力,应该大量推广毛白杨良种配制最佳施肥配比。【方法】以3个毛白杨良种为研究对象,利用不同施肥处理探明影响其重要生长性状的最佳施肥配比,并对高产优质毛白杨良种施肥响应特性相关的候选基因表达模式进行系统解析。【结果】‘毅杨1号’最佳施肥配比为N(3 g)+P2O5(2. 25 g)+K2O(1 g);‘毅杨2号’最佳施肥配比为N(3 g)+P2O5(2. 25 g)+K2O(0.5 g);‘毅杨3号’最佳施肥配比为N(7 g)+P2O5(2. 25 g)+K2O(0.5 g)。其中,氮元素是影响毛白杨毅杨良种的苗高、地径以及生物量最为显著的营养元素。为进一步解析其遗传调控基础,对与氮素运输、同化、代谢相关的16个重要候选基因在不同氮肥施肥水平下在叶片以及根系中的表达模式进行了解析。候选基因表达模式分析结果表明,毛白杨良种氮素相关候选基因在叶片以及根中聚类成不同的模块,并且无性系之间表达模式差异显著。【结论】本研究阐明了毅杨毛白杨良种的施肥响应特性,系统分析其转录调控特异性将有利于解析其氮肥响应特性形成的分子机制,并对进一步针对氮素吸收利用效率开展遗传改良的分子设计育种具有重要意义。

[Objective]The most suitable cultivation method for forest trees has an important impact on the improvement of forest productivity.Based on hybrid origin,Populus tomentosa individuals are significantly different in fertilization treatment response.In order to ensure the rapid growth and high-yield of plantation forest and reduce the pressure on environmental protection,the most suitable fertilization proportion should be formulated for elite of P.tomentosa.[Method]In this study,three improved varieties of P.tomentosa were used for different fertilization treatments.The most suitable fertilization proportion affecting their important growth traits were profiled.And the candidate gene expression patterns related to fertilizer utilization were systematically analyzed.[Result]The experimental results showed that the optimum fertilization proportion of‘Yiyang 1’is N(3 g)+P2O5(2.25 g)+K2 O(1 g);the optimum fertilization proportion of‘Yiyang 2’was N(3 g)+P2O5(2.25 g)+K2 O(0.5 g);‘Yiyang 3’was the best fertilization proportion of N(7 g)+P2O5(2.25 g)+K2 O(0.5 g).Among them,nitrogen is the most significant nutrient element affecting the seedling height,ground diameter and biomass of the improved species of P.tomentosa.To analyze the genetic basis of nitrogen utilization in poplar,the expression patterns of 16 candidate genes related to assimilation and metabolism of nitrogen transport in leaves and roots under different nitrogen fertilization levels were analyzed.The candidate genes’expression pattern analysis indicated that the nitrogen-related candidate genes of P.tomentosa were clustered into different modules in leaves and roots,and the expression patterns of clones were significant different.[Conclusion]This study preliminarily clarified that three improved forest varieties of P.tomentosa has significantly different fertilization response characteristics.Systematic analysis of their transcriptional regulation specificity will facilitate the analysis of molecular mechanism of their nitrogen fertilizer response characteristics and help for further molecular design of genetic improvement of nitrogen absorption and utilization efficiency in P.tomentosa.