落叶松凋落物层和土壤层1～5级细根形态和结构特征

Morphological and Structural Characteristics of 1-5 Order Roots in Litter and Soil Horizons of Larix gmelinii Rupr. Plantation

以黑龙江省帽儿山地区兴安落叶松(Larix gmelinii Rupr.)人工林为研究对象,比较了凋落物层和土壤层(0～30 cm深度,10 cm为间隔)1～5级细根直径、比根长、组织密度、分支比和分支强度的差异,以及这些特征在整个生长季中的变化。结果表明,随垂直层深度的增加,3～5级根直径增加、比根长下降,1～2级根的变化不明显,而组织密度没有明显变化规律。分支比和分支强度在凋落物层和土壤层间没有显著的差异。取样时间对直径、分支比和分支强度有显著影响,但与根序和垂直层存在交互作用。这些发现证实,落叶松根系资源觅食策略随生长环境的不同做出了改变。

We examined the underlying differences in the diameter,specific root length,tissue density,branching ratio and branching intensity of the first to the fifth order roots between litter and three soil horizons(0-30 cm depth with 10-cm intervals),and determined their variations among seasons in a Larix gmelinii Rupr. plantation in Maoershan Mountains,Heilongjiang Province,China. Our results showed that root diameter of the third to the fifth orders increased,specific root length decreased associated with vertical depth increasing,but those of the first two order roots did not show apparent trends. Tissue densities of all five order roots did not show clear variations with depth increasing. There were no significant differences in branching ratio and branching intensity of roots between litter layer and soil layers. Sampling time had significant impacts on root diameter,branching ratio and branching intensity,with significant interactions with branch order and vertical layer. Our findings suggested that root resources foraging strategy of L. gmelinii varied with the growing environments.