连香树人工林细根生物量分布及根系分泌速率季节变化研究

摘要

[目的]研究30年生连香树不同土层细根分布与生物量及根系分泌速率的季节动态变化过程,揭示根系分泌速率与细根之间的关系.[方法]以大沟流域30年生的国家二级濒危保护植物连香树人工林为研究对象,于2014年4、7、9和12月测定根系分泌速率和不同土层下细根的生长形态及生物量,比较他们在各季节间的变化情况,分析潜在的生态学意义.[结果]连香树细根在不同土层分布比例不一致,70.77%分布在0~15 cm土层,细根的根长、根重、根体积等形态参数随季节变化呈降低趋势,细根生物量呈先升高后降低的单峰型变化,7月最高,达280.74 g/m2,与其他月份的差异显著(P<0.05).随着季节的变化,根重分泌物DOC、TN速率、根长分泌物DOC、TN速率、根表面积分泌物DOC、TN速率均呈先升高后降低趋势,各季节间差异均显著,均在7月最高,12月最低.[结论]该研究可为连香树天然种群的保护和人工栽培提供科学依据.%[Objective]The study aimed to reveal the seasonal dynamics of fine root distribution and biomass of Cercidiphyllu mjaponicm Sideb.et Zucc.[Method]Taking the 30-year-old national endangered Cercidiphyllu mjaponicm Sideb.et Zucc plantation of the Dagou Valley,the root exudates and the growth and biomass of fine roots in different soil layers were measured in April 2014,the potential ecological significance was analyzed.[Result]The distribution of fine roots in the different soil layers was not consistent,70.77% in 0-15 cm soil layer.The root length,root weight and root volume of fine roots showed a decreasing trend with the seasonal variation (P<0.05).With the alternation of seasons and the change of temperature,fine root proliferation,the proliferation of fine roots in summer was the fastest,the root weight DOC,TN secretion rate,root length,TN DOC secretion rate,root surface area of DOC and TN secretion rate showed first increased and then decreased,the difference between each season was significantly,the highest in July and lowest in December.[Conclusion]The study can provide scientific basis for the conservation and artificial cultivation of natural populations Cercidiphyllu mjaponicm Sideb.et Zucc.