酸雨对植物地上部生理生态的影响研究进展与展望

Research advances and prospects for effects of acid rain on aboveground physiology of plants and related alleviation countermeasures

酸雨已成为我国长江以南和云南—贵州以东地区重要的生态环境问题之一.酸雨会给地面上植物产生"首当其冲"的影响,使其生长受阻.为全面了解酸雨对植物地上部生长产生的影响,详细阐述酸雨对植物地上部形态结构、物质代谢、抗氧化系统和光合作用等方面影响的研究进展,并进一步分析植物受酸雨胁迫的相关生理机制.酸雨首先会破坏植物叶绿体、线粒体等细胞结构,酸胁迫严重时会在叶上部和叶边缘产生明显的伤斑甚至导致植物萎蔫和死亡.其次,酸雨向植物体内输入过量的H+和氮硫化合物,会破坏氮代谢平衡,将矿质元素淋洗出来,造成植株营养缺失,进而影响叶绿素的合成和分解,降低植物的光合作用和生产力,影响植株的生长.与此同时,酸雨会导致植物体内活性氧的过量积累.此外,总结几种缓解酸雨对植物地上部危害的技术措施,如喷施叶面肥、喷施植物生长调节剂和接种外生菌根等.基于酸雨研究的现状与进展,未来该领域研究的重点可从以下几方面开展:(1)从形态结构学、生理生化和分子生态学等角度揭示酸雨胁迫下植物地上部与地下部的互作效应与机理;(2)加大酸雨和其他因素(如土壤重金属超标、紫外胁迫、病害胁迫等)复合胁迫的野外定位观测和田间试验综合研究;(3)从修复酸性土壤、开展生态栽培与环境友好型技术研究、调整种植结构等多方面研究植物酸害缓解措施.

Acid rain is widely distributed around the southward area of the Yangtze River and the eastward area of the Yunnan-Guizhou Plateau. It has become one of the most serious environmental problems in China. Acid rain first affects plants on the ground and hinders plant growth. To understand the stress and harm of acid rain on plant growth, this study reviewed and analyzed the research progress of acid rain on the morphological structure, material metabolism, antioxidant system, and photosynthesis of plant shoots through a literature review and analysis, and presented the relevant physiological mechanisms of acid rain stress in plants. Firstly,acid rain can destroy the cell structure of plant chloroplasts and mitochondria. When acid stress is severe, it can also produce obvious scars and cause plant wilting. Secondly, acid rain inputs excessive H+ and nitrogen and sulfur compounds into plants, disrupting the balance of nitrogen metabolism, leaching mineral elements,and causing plant nutrition deficiency. It then affects the synthesis and decomposition of chlorophyll, reducing photosynthesis and productivity of plants and affects plant growth. Acid rain simultaneously causes the excessive accumulation of reactive oxygen species in plants. This study summarizes several technical measures to alleviate the damage caused by acid rain to above-ground plants, such as spraying foliar fertilizer, spraying plant growth regulators, and inoculating ectomycorrhiza. As a continuation of the current status and advances in acid rain research, the focus of future research may include the following aspects: 1) to further determine the interaction effect and mechanism of the above-ground and underground parts of plants under acid rain stress, 2)to establish field experimental studies regarding the compound stress from acid rain and other factors, and 3) to investigate diversification measures to mitigate acid damage to plants.