芦竹的强碱适应策略及在赤泥堆场生态修复中的应用研究

Studies on strong alkali adaptive strategies of plants have been the foundation and focus of ecological restoration and development and utilization of alkaline tailings and saline-alkali soils. Red mud is waste residue with strong alkalinity after extracting alumina from bauxite. Due to difficult to resource utilization, red mud is treated mainly by outdoor pile-up, which occupied a lot of lands and will pollute the surrounding ecological environment and influence industrial and agricultural production and people's health. Therefore, this project will focus on Arundo donax, which is strong alkali resistance and has high energy value, and red mud disposal sites in Aluminum Corporation of China Limited, Guangxi branch. Through mixed cultivation soil and red mud, different levels of alkali stress and heterogeneous alkaline environment will be setup and then strong alkali adaptive strategies of A. donax will be studied from growth dilution/sacrifice, clonal integration, and interspecific facilitation. On this basis, the optimum ecological restoration technologies and management methods of A. donax will be explored, with the aims to reduce the ecological risk and to generate considerable economic benefits of red mud disposal sites. The project will provide new breakthrough point for researches on plant stress adaptation strategies and basis for pedogenesis, planting, harmless and economic use of red mud disposal sites, and also provide the reference and the model for ecological management and economic use of other similar tailings or saline-alkali soils.

植物对强碱胁迫的适应策略一直是碱性尾矿或盐碱地生态修复及开发利用研究的基础与热点。赤泥是铝土矿提炼氧化铝后排放的红色废渣，数量巨大且呈强碱性。由于资源化利用难度大，赤泥主要以露天堆存的形式占用大量的土地，而且易通过粉尘飘散或附液下渗污染周边生态环境，严重影响工农业生产及人们的身心健康。为此，本项目以耐强碱且具能源价值的芦竹及中国铝业股份有限公司广西分公司的赤泥堆场为研究对象，通过栽培土与赤泥混合设置不同程度的碱胁迫或异质性碱环境，从生长稀释/牺牲、克隆整合、邻体促进等全新的角度研究芦竹的强碱适应策略，并在此基础上，探索芦竹在赤泥堆场生态修复过程中的应用技术与管理方法，以降低赤泥堆场的生态环境风险并产生一定的经济效益。本项目的实施，将为植物逆境适应策略研究提供新的切入点，而且可为赤泥堆场的土壤化、绿化、无害化及经济利用提供依据，也为其他类似尾矿库或盐碱地的生态治理与经济利用提供参考与样板。

赤泥堆场是铝土矿提炼氧化铝后露天堆放红色废渣--赤泥的场所。由于赤泥强碱性（pH 10-12）、养分贫瘠、透水透气性差等，很少有植物能在堆场上生长，赤泥堆场的生态修复也鲜有成功的范例。芦竹是一种耐盐碱等多种逆境的能源植物，可用于盐碱地及适当改良或加有少量客土的赤泥堆场的植物修复。为阐明芦竹适应强碱的机制与策略及在强碱赤泥堆场的生态修复应用，本项目通过赤泥理化性质分析、芦竹水培扦插育苗研发、强碱胁迫下芦竹苗的转录组分析等，研究了芦竹的强碱适应策略、生态修复潜力与应用前景。在此基础上，研发了赤泥降碱等基质改良技术并以芦竹为主要修复植物建立了赤泥堆场生态修复示范点1个，面积约600 m2。转录组分析发现，强碱胁迫（pH 11）下芦竹共有10701个差异表达基因，其中有6896个上调基因，3805个下调基因。对差异表达基因进行GO富集分析，显著富集的GO terms包括对karrikin的响应、β-1,3-葡聚糖酶活性、氨基酸结合等。通过KEGG通路富集分析，差异表达基因主要涉及的代谢通路为氨基酸、半乳糖代谢途径等。同时，激素信号转导途径（如生长素、脱落酸）和转录因子（如ERF、WRKY、NAC家族）也被强碱胁迫诱导。这些结果表明芦竹通过调控氨基酸代谢、激素转导、转录因子表达等多基因合作提高其耐碱性，其强碱适应策略以生长稀释为主。应用于强碱赤泥堆场的生态修复时，芦竹仅需少量客土与有机肥添加至定植穴中，节约了巨大的覆土成本，而且整个定植过程简单易行，便于操作，易于快速绿化裸露的赤泥堆场。