不同时间添加蚯蚓对矸石覆土生理生态的影响

Effect of adding earthworms at different time points on the physiological ecology of Vetiveria zizanioides in covering soil of gangue

为探究不同时间添加蚯蚓对矸石覆土中香根草(Vetiveria zizanioides)生理生态的影响,采用土柱试验,设置两种覆土厚度[30 cm(M)、50 cm(N)],每组覆土分别设4个处理组:单独种植香根草(CK)、接种蚯蚓20 d后添加香根草(A)、同时接种蚯蚓和添加香根草(B)、添加香根草20 d后接种蚯蚓(C)处理,分析覆土理化性质及香根草生理生态指标变化特征。结果显示:与CK相比,A、B和C处理均能使覆土pH显著降低趋向中性(P<0.05),提升覆土电导率(EC)、有机质(OM)、全氮(TN)和全磷(TP)含量。与CK相比,不同时间接种蚯蚓均能增加香根草发芽率、总重和叶绿素a含量,其中B处理光合色素(叶绿素a、叶绿素b、类胡萝卜素)含量、A处理叶绿素b含量和C处理根系总长较CK均显著提高(P<0.05)。与CK相比,B处理降低香根草可溶性蛋白和脯氨酸含量效果较强,30和50 cm厚度覆土下B处理香根草可溶性蛋白较CK分别降低9.34%和4.69%(P<0.05),50 cm厚度覆土下脯氨酸含量较CK降低了5.55%(P<0.05),而A处理能显著提高香根草丙二醛含量。同一覆土厚度下,A处理仅在30 cm条件下显著降低香根草过氧化氢酶活性;B、C处理香根草超氧化物歧化酶、过氧化物酶活性较CK相比均无显著差异(P>0.05)。冗余分析和相关性分析表明:A、C处理中覆土OM、TN是影响香根草生理生态特性主要环境因子,而B处理中覆土OM、TP是影响香根草生理生态特性的主要环境因子。研究结果可为蚯蚓-香根草联合应用于复垦土壤修复提供理论依据。

This study was conducted to reveal the influence of adding earthworms at different time points on the physiological ecology of vetiver grass(Vetiveria zizanioides)in covering soil on the gangue.A soil column experiment was set up for two groups of overburden soil thickness[30 cm(group M)and 50 cm(group N)].Each group was set up with four treatments:vetiver grass planting alone(CK),20 days inoculation with earthworms followed by the addition of vetiver grass(A),inoculation with earthworms and vetiver grass at the same time(B),and 20 days of vetiver inoculation followed by the addition of earthworms(C).The physicochemical properties of the overburden soil and the physiological ecology of the vetiver grass were analyzed for different treatments.The results showed that treatments of A,B,and C all significantly reduced pH towards neutral and increased electrical conductivity(EC),organic matter(OM),total nitrogen(TN)and total phosphorus(TP)compared to CK(P<0.05).In comparison with CK,inoculation with earthworms at different times all increased vetiver grass germination,total weight and chlorophyll a content;treatment B increased photosynthetic pigment(chlorophyll a,chlorophyll b and carotenoid)content;treatment A increased chlorophyll b content;and treatment C increased root length(P<0.05).Treatment B was more effective in reducing the soluble protein and proline content of vetiver grass than other treatments.The reduction rate of soluble protein content in treatment B was 9.34%and 4.69%(P<0.05)in the 30 and 50 cm group,respectively,and proline content in treatment B was 5.55%(P<0.05)in the 50 cm group,as compared with the CK.While treatment A significantly increased the MDA content of vetiver grass.At the same thickness,treatment A reduced the CAT activity of vetiver grass only in the 30 cm group,but there was no significant difference in SOD and POD activities of vetiver grass in B and C treatments compared to CK(P>0.05).Correlation and redundancy analysis revealed that,soil OM and TN were the main environmental factors affecting physiological ecology of vetiver grass in treatments A and C,while soil OM and TP were the main environmental factors affecting physiological ecology of vetiver grass in treatment B.This study will provide a theoretical basis and data support for the combined application of earthworm and vetiver grass in reclaimed soil remediation.