中国温带、亚热带和热带森林45个常见树种细根直径变异  

VARIATION IN ROOT DIAMETER AMONG 45 COMMON TREE SPECIES IN TEMPERATE,SUBTROPICAL AND TROPICAL FORESTS IN CHINA

作　　者：常文静[1] 郭大立[2] 

机构地区：[1]北京大学深圳研究生院,深圳518055 [2]北京大学城市与环境学院生态学系,北京100871

出　　处：《植物生态学报》2008年第6期1248-1257,共10页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金资助(90511002和30470294)

摘　　要：细根在发挥植物功能以及生态系统碳和养分循环过程中起着重要作用。为了解我国不同森林生态系统细根直径变化规律,提供建立根系模型的基础,该文研究了我国温带、亚热带和热带45个常见树种1～5级根直径的变异以及直径与根序的关系。结果表明:1)在所有树种中,1级根直径最细,5级根直径最粗,直径随根序的增加而增加。此外,同一根序的直径在不同树种间变异较大,在不同生态系统中,各树种1级根的总体平均直径呈现温带<亚热带<热带的格局。2)不同生态系统树种同一根序平均直径变异程度不同,各个根序都是温带最小,亚热带次之,热带最大。3)细根内部各个根序的平均直径变异的52%由根序解释,33%由树种解释,生态系统类型和生活型分别解释7%和2%。不同系统不同树种直径的变异说明无法用统一的直径级来研究根的功能,也无法用统一的根序和直径间的关系来建立根系形态模型。今后的研究需要进一步认识根序和直径在不同树种中如何与根的功能相联系。Aims Fine roots play an important role in plant functioning and ecosystem carbon and nu- trient cycling. We studied root diameter across the first five branch orders of 45 tree species from three forest ecosystems in China, in order to： 1） examine fine root diameter distributions of various tree species in temperate, subtropical and tropical forests in China; 2） identify factors influencing the variations in root diameter; and 3） analyze the relationship between branch order and diameter. Methods Fine roots of 45 tree species were sampled by branch order in temperate, subtropical and tropical forests in summers of 2006 and 2007. Study sites included Beijing Baihua, Shanxi Guandi, Shanxi Zhongtiao and Guangdong Dinghu Mountains and Yunnan Xishuangbanna. We excavated soil blocks of 20 cm×20 cm×10 cm to sample intact fine root branches containing at least the first five branch orders, dissected these intact root branches by order and measured the diameters of individual roots of each order. Important findings Root diameter increases from first to fifth order, although the diameter of the same order varied markedly among species. On average, the diameter of tree species in the three forests is temperate 〈 subtropical 〈 tropical. Variations in diameter among species were different for the three forests： temperate 〈 subtropical ≤ tropical. Branch order can explain 52% of diameter variations, species 33%, ecosystem 7% and life form 2%. Key words fine root, diameter, order, temperate, subtropical, tropical

关 键 词：细根 直径 根序 温带 亚热带 热带 

分 类 号：Q944[生物学—植物学]