【摘要】 细根形态反映细根功能,以黄土高原陕西省永寿县15年生刺槐人工林为研究对象,采集刺槐完整根段,依据根序分成1～5级根,对其细根形态结构和生物量进行测定分析,为深入认识刺槐人工林细根形态特征提供参考。结果表明:1)1～2、2～3、3～4、4～5级根的平均分支比分别为4.52、2.06、4.03和4.17。其中,只有2～3级根的分支比与其他分支水平之间具有显著差异(P<0.05)。2)从1级根到5级根,随序级的升高,刺槐细根直径、根长呈升高趋势,而比根长呈降低趋势。各根序之间的细根直径、根长、比根长都具有显著差异(P<0.05)。3)刺槐1～5级细根生物量的排序为1级<2级<3级<5级<4级,且前4级之间的细根生物量具有显著差异(P<0.05)。1～5级细根总生物量为240.95g·m-2,4～5级根生物量之和占总生物量的75.88%,对总生物量有较大的贡献。1～5级细根各分支水平高级根与低级根的细根生物量之间具有显著的线性关系。更多还原

【Abstract】 Fine root morphology reflects the function of the fine root.This study was conducted in 15-yearold Robinia pseudoacacia plantations of the Loess Plateau,located in Yongshou County,Shaanxi Province,China.Intact fine root segments of R.pseudoacacia were collected by excavation in the plantations.Individual roots were dissected according to the branching order,starting from the distal end of the root system that was numbered as the first order and then increasing sequentially with each branch from the first order to fifth order roots.The fine root morphology and biomass of the first five orders were measured and analyzed.The results showed that:1)the average ratios of branching(Rb)of 1-2,2-3,3-4 and 4-5 levels were 4.52,2.06,4.03 and 4.17 respectively.The ANOVA demonstrated that the Rb of 2-3 level was significantly significant from those of 1-2,3-4 and 4-5 levels(P<0.05).2)From first order to fifth order root,fine root diameter and root length showed increasing trend with the increase of order,while specific root length showed decreasing trend with the increase of order.The root diameter,length and specific root length were significantly different among orders(P<0.05).3)From the first to fifth order,fine root biomass was in an order of 1<2<3<5<4.And the fine root biomass between the first four grades was significantly different(P<0.05).The total fine root biomass of the first to fifth order was 240.95 g·m-2.The fourth to fifth order roots accounted for 75.88%of the total biomass,and had a greater contribution to the total biomass.From the first to fifth order,there was a significant linear relationship between the fine root biomass of lower level and higher level.更多还原