白龙江上游植被演替过程中表层根生物量的积累与分配

Accumulation and distribution of root biomass changedwith vegetation succession in the upper reachesof Bailong River

摘要:

根是植物固着与吸收养分的器官,了解不同植被类型根生物量分配及空间特征有助于揭示高山地区物种分布特征及生活史对策。采用土块全挖法,对白龙江沙滩林场森林植被演替过程中的3种植被类型(灌丛(柳)、红桦林和冷杉林)根生物量进行了测定。结果表明:亚高山森林植被演替过程中,粗根生物量与中根生物量垂直分布有差异性,且土层深度对中根生物量分配比例有显著影响。植被演替过程中,粗根系生物量先减小后增加,细根生物量先增加后减小。异速生长分析表明:林场区域内,中根生物量与细根生物量为等速生长,细根生物量与粗根以及中根的累计生物量为异速生长。

Abstract:

Roots are the most important organ for plant fixation and nutrient absorption.Understanding the distribution of root biomass and spatial characteristics would be helpful to reveal the distribution of species and their life history strategies in alpine areas.In August 2019,the root biomass of different stands including shrub(willow),red birch and fir at Bailongjiang Beach Forest Farm was determined by using the whole earth excavation method.The results showed that the vertical biomass distribution of thick roots was different from that of medium roots.Soil depth had a significant influence on the proportion of biomass of roots in medium thickness in the subalpine forest.In the process of vegetation succession,the biomass of thick roots first decreased and then increased,and the biomass of fine roots first increased and then decreased.The results of allosteric growth analysis showed that the biomass of medium roots and fine roots showed the same growth rate,while the biomass of fine roots,thick roots and medium roots showed different growth rates.The root distribution characteristics of forest vegetation reflected the difference in carbon assimilation,which would be helpful to reveal the dynamic mechanisms of forest growth and development,therefore providing scientific basis for forest structure optimization.