汶川震区不同气候区受损植被土壤有机碳储量和碳密度分布特征

采用ISSR分子标记技术,对广西特有珍稀濒危植物小花异裂菊6个野生种群的遗传多样性进行了研究。结果表明：10条引物对141个个体共检测到96个位点,其中29个位点具有多态性,多态位点百分率( PPB)为30.21％。在物种水平上,小花异裂菊 PPB 为30.21％, Nei ’ s 基因多样性指数( H )为0.1054, Shannon’s信息指数(I)为0.1546。在种群水平上,PPB 为9％~19％,H 为0.0212~0.0513,I 为0.0339~0.0805。基于Nei’ s遗传多样性分析所得出的种群间基因分化系数Gst＝0.6905,表明种群内的遗传变异为30.95％,种群间的遗传变异为69.05％,小花异裂菊的遗传变异主要存在于种群间。 AMOVA分析结果与前面结果相符。小花异裂菊种群间的基因流( Nm)为0.2242。从遗传距离看,杨堤和兴坪种群的遗传距离最小,为0.0398,白沙和阳朔之间的遗传距离最大,为0.1609。在UPGMA聚类图中,6个种群可分为两组,阳朔和高田为一组,普益、白沙、兴坪、杨堤聚为一组。研究认为小花异裂菊的自交亲和的繁育系统和分布区域的片段化可能是导致种群遗传多样性较低和种群间高遗传分化的主要原因。该研究结果为该物种种质资源的保护提供了科学依据。

Distribution characteristics of soil organic carbon storage and carbon density from damaged vegetation under different climate types in Wenchuan earthquake region

Taking typical regions affected by Wenchuan earthquake as research area including semi-arid dry warm river valley and subtropical humid monsoon climates, we set up the undestroyed region(UR)and destroyed and treated region(DR)as sampling plots. We determined soil water content, bulk specific gravity and organic carbon(soil organic carbon, SOC)content in different levels(0-5, 5-10, 10-20 cm). We analyzed the distribution characteristics between undestroyed region and destroyed and treated region in different climatic regions. The results were as follows:(1)SOC content of each soil layer in UR was significantly higher than that of DR in two typical climatic regions(P<0.05), while SOC increased first and then decreased with the soil depth. The SOC content in different soil layers in the same climatic region had no significant difference(P>0.05)with a fluctuated trend.(2)SOCD in UR was significantly higher than that in DR(P<0.05)and increased with the soil depth. It did not show significantly different(P>0.05)in different soil layers in the same climatic region.(3)Treatments in both climatic regions significantly influenced SOC content, but the interaction between treatments and soil layers and the influence of different soil layers was not significant(P>0.05). Different treatments and soil layers as well as their correlation significantly influenced SOCD(P<0.01), the interation between treatments and climate types was significantly different(P<0.05). The results indicate that soil organic carbon content in destroyed and treated region is lower than that in undestroyed region. Our results will supply the data for evaluating the effects of ecological restoration measures.