两种不同污染生态型假俭草对重金属铅吸收、转运及耐性差异机制研究

Ecological, food and human health problems caused by heavy metal are urgent, and phytoremediation is significant to urban ecological environment. Centipedegrass（Eremochloa ophiuroides (Munro) Hack.）, as an excellent groundcover plant in urban plant communities, is outstanding in endurance and accumulation of heavy metal lead (Pb), but little is available to explain this fundamental cause. In previous experiments, we found metallicolous (M) and nonmetallicolous (NM) centipedegrass which showed significant different proformance in the phytoremediation of Pb. In this project, taking into account of the difference mechanism between two ecotypes, techniques such as stable isotope tracing, EXAFS, NMT, ICP-MS were used to examine Pb absorption, transport pathway and tolerance characteristics from the physiological and biochemical level under hydroponic culture. By using a combination of transcriptomics and Lable-free proteomics analyses, molecular mechanisms of Pb tolerance and accumulation are studied. The research is great significance to establish theoretical foundation about the ecological restoration function and selection of garden plants under the background of dual urban renovation.

土壤重金属铅引发的生态、食品和人体健康问题已成为刻不容缓的社会问题，园林植物修复城市生态环境具有重大现实意义。假俭草（Eremochloa ophiuroides (Munro) Hack.）是城市园林中优良的地被植物，对重金属铅（Pb）具有很强的耐受和积累能力，目前对其铅吸收、转运及耐性机制尚不清楚。本课题以前期筛选出的铅富集与耐受性明显不同的两种不同铅污染生态型假俭草为研究材料，采用溶液培养法，运用同位素示踪技术、EXAFS技术、NMT、ICP-MS等对比分析不同生态型假俭草对铅吸收、转运和耐受的生理机制。利用转录组测序和Label-Free 技术分析假俭草在铅处理前后转录及蛋白水平的变化，从转录组和蛋白质组学角度解析其在耐铅过程中的分子机制。该研究从生理、分子生物学水平科学阐明假俭草对重金属铅的修复机制，为城市双修背景下发挥园林植物生态修复功能及园林植物的选择奠定坚实理论基础。

土壤重金属铅引发的生态、食品和人体健康问题已成为刻不容缓的社会问题，园林植物修复城市生态环境具有重大现实意义。假俭草（Eremochloa ophiuroides (Munro) Hack.）是城市园林中优良的地被植物，对重金属铅（Pb）具有很强的耐受和积累能力，目前对其铅吸收、转运及耐性机制尚不清楚。本项目以前期研究获得的重金属铅土壤适应型（ME型）和非重金属铅土壤适应型（NME型）假俭草为试验材料，采用溶液培养法，对比研究了两种生态型假俭草在梯度浓度铅胁迫处理下的毒害症状、生长状况、酶活性和非酶物质含量变化、抗逆生理指标的相关性及生理抗性贡献，揭示了ME型假俭草更耐受铅的生理调控机制；通过测定假俭草各部位铅含量、铅积累量及转运系数，明确了两种生态型假俭草铅吸收、转运的差异。在此基础上，根据前期研究结果，重点以ME型假俭草为研究材料，运用电感耦合等离子体质谱仪（ICP-MS）、透射电子显微镜（TEM）、傅里叶光谱（FTIR）和荧光染色等技术，综合探讨了外源低分子有机酸对假俭草铅吸收积累、铅耐受性的影响及其介导的铅解毒机制；同时拓展研究了生物可降解螯合剂氨三乙酸（NTA）对假俭草矿质元素及铅吸收转运的调控作用，探明了NTA促进假俭草高效转运铅的作用机理。该研究科学阐明了假俭草耐受和修复重金属铅的生理生态机制，为城市双修背景下发挥假俭草生态修复功能提供了坚实理论基础，并为假俭草联合外源辅助措施在土壤铅污染修复中的应用提供了科学依据。