极端干旱区胡杨细根的垂直分布和季节动态  

Vertical distribution and seasonal dynamics of fine roots in Populus euphratica plantation in the extremely drought area

作　　者：夏延国[1] 董芳宇 吕爽[1] 王键铭[1] 井家林[1] 李景文[1] 

机构地区：[1]北京林业大学林学院

出　　处：《北京林业大学学报》2015年第7期37-44,共8页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(310575332);林业行业公益重大专项(201404304)

摘　　要：以额济纳胡杨天然林为研究对象,用Minirhizotron方法对胡杨细根的垂直分布和季节动态进行了研究。研究结果表明：1）总体上,0~20 cm土层中胡杨细根的根长密度和根表面积密度最大,且与其他各层存在显著差异（P〈0.05）;2）在生长季,0~40 cm土层胡杨细根的生长率和生死之比均大于40~80 cm土层;3）胡杨细根的根长密度、根表面积密度和生长率均表现出单峰的季节变化趋势;死亡率在生长季呈逐渐增大的趋势;生死之比在生长季呈现出逐渐减小的季节变化趋势,而且仅在末期小于1,说明胡杨细根的季节动态是一个以生长占优势的生死交织的过程;4）生长率和死亡率均与土壤温度存在极显著正相关性（P〈0.01）;生长率与土壤含水量存在极显著正相关性（P〈0.01）,而死亡率与土壤含水量的相关性均不显著（P〉0.05）。Using the minirhizotron technique,we investigated the vertical distribution and seasonal dynamics of fine roots of Populus euphratica,the dominant tree species of the riparian forests in the extremely drought area in Ejina,Inner Mongolia. The results showed that： 1） In general,the maximum of root length density and root surface area density appeared in the 0- 20 cm soil layer（ P〈0. 05）. 2） The average growth rate and the ratio of growth rate to death rate in the top soil layer（ 0- 40 cm） were both higher than those in the deep soil layer（ 40- 80 cm） in the growing season. 3） As a whole,the root length density,root surface area density and growth rate showed a similar seasonal tendency with the peak value occurring in the middle period of growing season,but the death rate increased gradually. Meanwhile,the ratio of growth rate to death rate decreased gradually from April to September and dropped to 〈1 at the end of the growing season. 4） The seasonal changes of growth rate and death rate were significantly and positively correlated with soil temperature（ P〈0. 01）,and there was a significant correlation between growth rate and soil water content（ P〈0. 01）. However,no significant correlation could be detected between seasonal change of death rate and soil water content（ P〉0. 05）.

关 键 词：胡杨 细根 生长 土壤温度 土壤含水量 

分 类 号：S718.59[农业科学—林学] S792.119