不同喀斯特小生境下普定杜鹃花土壤酶活性变异特征

Variation characteristics of soil enzyme activity of Rhododendron pudingense habitat in different karst microhabitats

  • 摘要: 【目的】研究典型喀斯特不同小生境下土壤酶活性及其变异特征,为喀斯特地区植被恢复提供科学依据。【方法】以贵州喀斯特区(镇宁县、晴隆县、望谟县)的圆果化香树+普定杜鹃花(Rhododendron pudingense)群落为对象,通过测定3种小生境(土面、石沟、石面)中土壤胞内酶(脲酶、蔗糖酶、纤维素酶、蛋白酶)和胞外酶[(酸性磷酸酶(AP)、过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)]活性,分析其在不同小生境中的变异特征及其与环境因子的相互关系。【结果】 3种小生境下胞内酶和胞外酶均呈现出土面>石沟>石面,且胞内酶活性均小于胞外酶,胞外酶约占总体酶活性的93%;不同小生境下土壤酶活性差异显著(P<0.05),除晴隆的群落土壤脲酶、POD和SOD活性表现为土面>石面>石沟外,其余的土壤酶活性均为土面>石沟>石面;土壤酶活性受到群落中植物物种多样性影响,晴隆的群落中植物生长最旺盛,土壤酶活性相较于镇宁和望谟更高;小生境间的差异性影响土壤酶活性变化,尤其是水分、温度、腐殖质含量及土壤厚度等影响较大,而生境间差异导致地上植物多样性丰度不均,对底物供应也具有一定影响;喀斯特土面小生境条件最优,最适合植物生长,石沟小生境次之,石面小生境条件最差。【结论】喀斯特生境土壤酶活性受小生境类型影响,土面小生境土壤的酶活性普遍高于石沟和石面,土壤酶活性变化一定程度解释特有种普定杜鹃花生长在喀斯特小生境。

     

    Abstract: 【Objective】 To investigate soil enzyme activity and its variation characteristics in different microhabitats of typical karst areas, and to provide scientific basis for vegetation restoration in karst regions.【Method】 Platycarya longipes+ Rhododendron pudingense communities in karst regions of Guizhou(Zhenning County,Qinglong County and Wangmo County)were taken as research object. Activities of soil intracellular enzymes(urease,sucrase,cellulase and protease) and extracellular enzymes[acid phosphatase(AP),peroxidase(POD),catalase(CAT)and superoxide dismutase(SOD)] in 3 microhabitats[soil surface (SS), rock gully (RG), rock surface (RS)]were determined to analyze variation characteristics of enzymes activity in different microhabitats and their relationships with environmental factors.【Result】 In 3 microhabitats,activity of intracellular and extracellular enzymes was as SS>RS>RG,and activities of all intracellular enzymes were lower than activities of extracellular enzymes which accounted for 93% of total enzymes activity; significant difference in soil enzyme activity was found among different microhabitats(P<0.05). Except for that the urease,POD,and SOD activities in Qinglong’s community showed a trend of SS>RS>RG,activity of the rest soil enzymes followed a trend of SS>RG>RS;soil enzyme activity was influenced by plant species diversity in the community,and as plants grew the most vigorously in the community of Qinglong,soil enzyme activity in Qinglong was higher than that in Zhenning and Wangmo.Differences among microhabitats (especially differences in moisture,temperature, humus content, and soil thickness)greatly affected soil enzyme activity,and differences among microhabitats led to uneven abundance of above-ground plant diversity,thereby influencing substrate supply,which imposed a certain impact;in karst region,SS boosted the best microhabitat condition,which was the most suitable for plant growth,followed by RG,and RS had the poorest condition. 【Conclusion】Soil enzyme activity in karst habitats is influenced by microhabitat type and soil enzyme activity in microhabitat of soil surface is usually higher than that of rock gully and rock surface. Variation of soil enzyme activity explains the growth of endemic R. pudingense in karst microhabitats to a certain degree.

     

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