南亚热带4个不同演替阶段树种苗木环境适应性研究  

STUDY ON ADAPTABILITY TO ENVIRONMENT FOR 4 TREE SPECIES AT DIFFERENT SUCCESSIONAL STAGES GROWN IN SOUTH SUBTROPICAL ZONE

作　　者：杨小波[1] 

机构地区：[1]海南大学生物研究中心,海口570228

出　　处：《林业科学》2002年第1期56-60,共5页Scientia Silvae Sinicae

摘　　要：本文用净光合作用速率为指标从生态位宽度、重叠和理论生态位中心与现实生态位中心的偏离程度等方面来探讨不同演替阶段森林群落的优势树种苗木对环境适应性的问题 ,并采用同位素技术研究了光环境与苗木光合产物的输出和分配的关系。研究结果表明 ,森林演替先锋树种马尾松的苗木对土壤含水量变化 (变旱 )和全日照的光环境的适应性最强 ;演替后期种黄果厚壳桂对土壤含水量的变化的适应性最差 ;演替过渡种藜蒴对pH值的变化适应性最强 ,演替后期种黄果厚壳桂的适应性最差 ;生态位宽度与生态位中心偏离值都表现出演替过渡种藜蒴和荷木对矿物质浓度梯度变化适应性最强 ,这与它们苗木有较发达的根系相关密切 ,从而反映了森林演替过渡种比先锋树种和演替后期种有较强的对矿物质营养浓度等条件变化适应性。 4个树种苗木的生态位重叠度都较高 ,说明在森林演替过程中 ,各阶段的树种对资源的竞争是比较激烈的。同时光合产物输出与分配规律的研究结果还表明了 ,弱光对森林演替先锋树种马尾松的光合产物的输出与分配是不利的 。Response of dominant tree seedlings from secondary successional forests to gradients of pH value,moisture,nutrients and light was studied in order to further test the adaptability of dominant tree seedlings to the environment in the south subtropical zone,Guangdong Province,China.These species were Pinus massoniana (pioneer species),\%Schima superba and Castanopsis fissa\% (transitional species),\%Cryptocarya concinna\% (late successional species).The techniques to determine the response of these species seedlings to the gradients of the environment were ecophysiological technique by combining niche breadth,niche overlap and deviation from the central value of the niche.The data were the rate of net photosynthesis and the export and distribution of photosynthetic product determined by 14 C glucose treatment.The pioneer seedlings exhibited the highest rate of net photosynthesis and export and distribution of photosynthetic product to growth bud in the high light,also exhibited the largest niche breadth and deviation value at the soil moisture gradient,the late successional species seedlings was contrary.These values in the pioneer seedlings decreased when seedlings were transferred to low light condition for l year,and the seedlings of both transitional and late\|successional species had the highest rate of these in the forest gap habitats,no in some shade habitats. Because of the development of root system,the transitional tree seedlings showed the largest niche breadth and deviation value at the nutrient and pH value gradient,and pioneer seedlings were contrary at nutrient gradient,late\|successional seedlings were contrary.Finally,the value of the niche overlap of these seedlings showed that strong competition among tree species in the successional forest communities.

关 键 词：生态位 群落优势种 森林次生演替 环境适应性 苗木 净光合作用速率 

分 类 号：S718.54[农业科学—林学]