甲壳素对连作条件下平邑甜茶幼苗生长及土壤环境的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 甲壳素对连作条件下平邑甜茶幼苗生长及土壤环境的影响 DOI: 10.5846/stxb201501270221 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 现代农业产业技术体系建设专项资金（CARS-28）；教育部长江学者和创新团队发展计划（IRT1155）；泰安市科技发展计划项目（32802） Effects of chitin on the growth of Malus hupehensis Rehd. seedlings and soil environment under replant condition Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究在苹果连作土壤中添加甲壳素对苹果幼苗生长、土壤酶及土壤真菌群落结构的影响，探讨甲壳素缓解苹果连作障碍的可能性，为防控苹果连作障碍提供依据。盆栽条件下，以平邑甜茶幼苗为试材，在苹果连作土壤中分别添加0，0.5，1.0和2.5 g/kg的甲壳素，测定了连作土壤中添加不同量的甲壳素后，幼苗生物量、根系保护酶活性、土壤主要酶（蔗糖酶、脲酶、磷酸酶等）活性以及土壤中真菌群落结构的变化。9月份结果表明，与对照相比，1.0 g/kg的甲壳素处理连作土，可显著提高平邑甜茶幼苗株高和干鲜重，分别比对照增加了36.8%、82.1%和100.8%；甲壳素处理能增加幼苗根系保护酶活性，其中1.0 g/kg甲壳素处理SOD、POD和CAT活性最高，其次为0.5 g/kg，而2.5 g/kg甲壳素处理显著抑制了幼苗根系保护酶活性。1.0 g/kg甲壳素处理可提高土壤中细菌/真菌值，并且提高了土壤中蔗糖酶、脲酶、蛋白酶、磷酸酶、过氧化氢酶和多酚氧化酶活性，分别比对照提高了8.6%、40.5%、81.1%、15.3%、18.7%和49.8%，2.5 g/kg甲壳素处理则降低土壤酶活性或者使土壤酶活性与对照相当。根据T-RFLP的图谱中OUT的数量、种类及丰度，分别计算了不同处理土壤的真菌多样性，发现1.0 g/kg甲壳素处理的连作土具有最高的多样性、均匀度和丰富度指数，分别比对照增加了52.2%、8.0%和87.1%。主成分分析（PCA）结果显示，不同剂量甲壳素处理的连作土壤中真菌被PC2分成了两部分，其中0.5 g/kg和1.0 g/kg的甲壳素添加量分布在PC2的负方向上，而CK和2.5 g/kg的甲壳素处理分布在PC2的正方向上，这说明添加不同量的甲壳素对连作土壤真菌群落多样性有显著影响，添加量太多或者太少均会造成土壤真菌多样性下降，只有适量的甲壳素可提高真菌群落结构多样性。实验结果表明1.0 g/kg的甲壳素可提高连作平邑甜茶幼苗生物量，改善连作土壤环境，有效缓解平邑甜茶的连作障碍。 Abstract:The effects of different concentrations of chitin on the activity of enzymes and fungal communities existing in replant soils were explored, for enrichment of soils to alleviate apple replant disease (ARD). In this study, Malus hupehensis Rehd. seedlings potted in replant soil were treated with four concentrations of chitin (0, 0.5, 1.0, and 2.5 g/kg). The growth of seedlings was monitored though plant height, fresh and dry weight, antioxidant enzyme activities, such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and lipid peroxidation in roots. Simultaneously, soil enzyme activities, soil microbial load, and fungal community structure, which was measured by terminal-restriction fragment length polymorphism (T-RFLP) profiles, were determined in soil samples subjected to the four chitin treatments. Compared with the control, seedlings treated with 1.0 g/kg chitin showed 36.8%, and 82.1% and 100.8% increase in plant height, and fresh and dry weight, respectively. The optimal dose of chitin could increase antioxidant enzyme activity in the root system of the seedlings, whereas high doses inhibited enzyme activity. The effectiveness of chitin treatment for inhibiting the activity of SOD, POD, and CAT in the root system of M. hupehensis seedlings decreased in the following order:1.0 g/kg > 0.5 g/kg > 0 g/kg > 2.5 g/kg. Chitin treatment at 1.0 g/kg enhanced the bacterial-fungal ratio, and resulted in a "bacteria-rich soil"; consequently, sucrase, urease, protease, phosphatase, catalase, and polyphenol oxidase activities increased by 8.6%, 40.5%, 81.1%, 15.3%, 18.7%, and 49.8%, respectively. Remarkable differences in T-RFLP profiles were observed among control, 0.5 g/kg, 1.0 g/kg, and 2.5 g/kg treatments. A significant difference in fungal community structure was observed with the application of different doses of chitin. The Shannon diversity, evenness, and richness indexes were the highest in replanted soil treated with 1.0 g/kg chitin and the least in soil treated with 2.5 g/kg chitin. Principal component analysis indicated that fungal community structure of soil treated with 1.0 g/kg chitin was considerably different from that of the control soil and soil treated with 2.5 g/kg chitin. The present study showed that low concentrations of chitin could alleviate ARD stress in M. hupehensis Rehd. seedlings, whereas high concentrations could aggravate ARD stress. Collectively, these findings suggest that chitin applied to replant soil at 1.0 g/kg obviously enhanced plant height, fresh and dry weight, improved the soil environment, and effectively alleviate ARD stress in M. hupehensis Rehd. seedlings, therefore, a chitin dose of 1.0 g/kg was considered optimal for replant soil. 参考文献 相似文献 引证文献