毛竹向杉木林扩展过程中细根适应策略

Fine root adaptation strategy of moso bamboo during its expansion into Chinese fir forest

毛竹向周边系统扩展的能力很强,研究毛竹扩展过程中细根的适应策略,可以为毛竹林扩展调控提供科学依据。本研究以毛竹-杉木林扩展界面为对象,分析了毛竹不同扩展阶段细根生物量、根长密度、比根长及细根养分含量和比值的变化。结果表明:随着毛竹扩展,细根生物量和根长密度增加,比根长、细根N和P含量降低;与扩展前期相比,扩展后期细根生物量、根长密度分别是扩展前期的7.03、1.57倍,分别为1683.04±188.17 g·m^2和6483.14±846.82 m·m^(-3);比根长从扩展前期的2.61±0.20 m·g^(-1)降低到到扩展后期的0.70±0.06 m·g^(-1),扩展前期是扩展后期的3.73倍;细根N含量从扩展前期的5.06 g·kg^(-1)降低到扩展后期的2.98 g·kg^(-1),降低了41.11%; P含量从扩展前期的0.30 g·kg^(-1)降低到扩展后期的0.17 g·kg^(-1),降低了43.33%。相关分析表明:细根生物量、比根长与细根N、P、K、C∶N之间的相关性达到极显著水平,毛竹细根养分含量与细根形态特征协同发生了变化;毛竹向杉木林扩展时,细根形态和主要养分含量随着环境的变化发生了适应性的改变,毛竹细根具有较强的可塑性;毛竹细根在扩展前期通过增加比根长和细根N、P含量的策略,实现在新环境中的快速生长和对土壤环境的高效利用。

Fine roots are important for the function of individual plants.To better reveal the fine root strategy of bamboo expansion,we explored its plasticity in the process of Phyllostachys edulis expanding into Chinese fir forest.We compared the functional traits of fine roots of moso bamboo in different stages and explored the morphological plasticity when it expanded into Chinese fir forest.The fine root biomass(FRB),root length density(RLD),specific root length(SRL),key nutrient contents and their ratios were measured.The results showed that the FRB and RLD increased with moso bamboo expansion.The SRL and the content of N and P decreased with moso bamboo expansion.The FRB and RLD at final expansion stage were 7.03 times and 1.57 times of that at the initial expansion stage.The FRB and RLD at final expansion stage were 1683.04±188.17 g·m2 and 6483.14±846.82 m·m-3,respectively.The SRL decreased from 2.61±0.20 m·g-1 at initial expansion stage to 0.70±0.06 m·g-1 at the final expansion stage,with the former being 3.73 times that of latter.The N content decreased by 41.11%,from 5.06 g·kg-1 at initial expansion stage to 2.98 g·kg-1 at the final expansion stage.The P content decreased by43.33%,from 0.30 g·kg-1 at initial expansion stage to 0.17 g·kg-1 at final expansion stage.There were significant correlations between N,P,K contents,C∶N and the FRB and SRL,indicating that the morphological traits and nutrient contents of fine roots varied with environmental changes and that the fine roots of moso bamboo had higher plasticity.The moso bamboo can grow quickly and use soil resources efficiently in new environment by increasing the SRL and N and P contents.