Kummerow Jochen, Krause David, Jow William
Botany Department, San Diego State University, 92182, San Diego, CA, USA.
Oecologia. 1978 Jan;37(2):201-212. doi: 10.1007/BF00344991.
Fine root extractions from soil cores of a south facing slope in the Southern Californian chaparral were used to study the dynamics of feeder root growth in a summer-dry area. The studies were concentrated on the root systems of Adenostoma fasciculatum, Arctostaphylos glauca, Ceanothus greggii, and Rhus ovata. The total fine root biomass of Adenostoma fasciculatum increased from 0.6 g dm in early spring to 3.6 g dm in late summer. Considering the specific soil conditions at this site and earlier gained information on fine root distribution with depth, the value of 3.6 g dm converts to 1.58 kg m of ground shaded by the shrub canopy. The observed seasonal biomass increase is mainly due to the accumulation of dead root material in the soil when low soil moisture contents presumably inhibited decomposition processes. The total length of living fine roots also increased during the season, e.g. from 0.8 m dm to more than 5 m dm (0.35 km m to 2.2 km m) in A. fasciculatum. Unusual summer rains in the research year stimulated vigorous fine root growth at a time when the normally low soil moisture would prohibit further fine root growth. The average fine root diameters and total lengths of fine roots beneath one square meter of ground surface allowed an estimate of root area indices (RAI) analogous to the leaf area indices (LAI). The data provide evidence for a significant fine root turnover in the chaparral.
从南加州丛林朝南斜坡的土壤芯中提取细根，用于研究夏季干旱地区须根生长的动态。研究集中在丛生腺柳、灰熊葡萄、格雷格氏鼠李和卵形盐肤木的根系上。丛生腺柳的细根总生物量从早春的0.6克/立方分米增加到夏末的3.6克/立方分米。考虑到该地点的特定土壤条件以及早期获得的细根随深度分布的信息，3.6克/立方分米的值换算为灌木冠层遮蔽地面的1.58千克/平方米。观察到的季节性生物量增加主要是由于土壤湿度较低可能抑制分解过程时，土壤中死根物质的积累。活细根的总长度在季节中也有所增加，例如丛生腺柳从0.8米/立方分米增加到超过5米/立方分米（0.35千米/平方米到2.2千米/平方米）。研究年份异常的夏季降雨在正常土壤湿度较低会阻止进一步细根生长的时候，刺激了细根的旺盛生长。一平方米地面下细根的平均直径和总长度使得能够估计类似于叶面积指数（LAI）的根面积指数（RAI）。数据为丛林中显著的细根周转提供了证据。
