摘要
以郁闭度分别为40%、60%和70%的蒙古栎林、针阔混交林和次生杂木林3种生境下野生刺五加种群为材料,考察了其生长发育、光合色素和光合特性的变化,探讨刺五加种群对光照条件的适应机制,寻找有利于刺五加种群生长和更新的适宜天然条件,为人工抚育生境的选择和促进天然次生林更新提供科学依据.结果表明:(1)不同生境下刺五加种群个体株高、基径和生物量均表现为蒙古栎林>针阔混交林>次生杂木林;随着郁闭度的增加,刺五加种群叶构件生物量比率呈现增加的趋势,而茎构件和根茎构件生物量比率则呈现下降的趋势.(2)刺五加种群叶绿素a、叶绿素b、类胡萝卜素含量随着生境郁闭度增加呈逐渐增加趋势,而叶绿素a/b却呈下降趋势.(3)随着郁闭度的增加,刺五加种群的净光合速率、气孔导度、蒸腾速率、水分利用效率、气孔限制值、光饱和点、光补偿点和暗呼吸速率等光合参数均显著降低,而胞间二氧化碳浓度却显著提高.(4)蒙古栎林下刺五加种群具有相对较高的净光合速率和水分利用效率,从而带动种群各构件旺盛生长,使其个体株高、基径、各功能构件生物量均显著高于针阔混交林和次生杂木林种群;光能不足是限制次生杂木林刺五加种群生长的主要因子之一.因此,在抚育刺五加人工林的过程中,应该充分考虑郁闭度对刺五加种群生长发育的影响,同时还要考虑其他植物对刺五加种群生态位的竞争,并以在郁闭度40%的蒙古栎林下抚育为佳.
The experiments took wild Acanthopanax senticosus（Rupr.et Maxim.） Harms in three different habitats of Quercus mongolica forest（canopy density of 40%）,theropencedrymion（canopy density of 60%） and secondary miscellaneous forest（canopy density of 70%） as material,and the growth,photosynthetic pigments and photosynthetic characteristics of A.senticosus were studied,in order to investigate the adaptability of the species to different light conditions,determinate the feasible natural condition for growth and regeneration of A.senticosus and provide scientific evidences for selecting artificial tending of woods and promoting regeneration of natural secondary forest.The results showed：（1）the height,basal diameter and biomass were the order of that Q.mongolica foresttheropencedrymionsecondary forest.The leaves biomass ratio increased with the increasing of canopy density,but the stems and rhizomes biomass ratio decreased.（2）The contents of chlorophyll a,chlorophyll b and carotenoids in leaves increased with the increasing of shading levels,however,the variation trend of chlorophyll a/b was contrary.（3）The net photosynthetic rate,stomatal conductance,transpiration,water use efficiency,stomatal limitation values,light saturation point（LCP）,light compensation point（LSP） and Rd decreased markedly with the increasing of canopy density,but the intercellular CO2 concentration increased significantly.（4）A.senticosus population had higher net photosynthetic rate and water use efficiency in Q.mongolica forest with canopy density of 40%,which bring every module grow well.The height,basal diameter and each module＇s biomass of the A.senticosus population in Q.mongolica forest were larger than that in theropencedrymion and secondary miscellaneous forest.The weak illumination was one of the most important environmental factors constraining plant population growth in the secondary miscellaneous forest.So the effects of canopy density on growth of A.senticosus population must be carefully considered in artificial nurturing of the species,and the competitions of other plants on ecological niche of A.senticosus population also should be considered.And our results suggest that Q.mongolica forest with canopy density of 40% should be selected when nurturing of A.senticosus.
出处
《西北植物学报》
CAS
CSCD
北大核心
2011年第9期1852-1859,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
吉林省科技发展计划重大项目(20075022)
吉林农业大学博士启动基金(2011112)
关键词
生物量
净光合速率
叶绿素
郁闭度
biomass
net photosynthetic rate
chlorophyll
canopy density
