Salinity-alkalinity stress (SAS) is one of the major abiotic stresses affecting the growth and development of plants and has been a severe problem that restricts crop production and even the development of the ecological environment.It is vital to understand the mechanisms behind the response to SAS in plants for effective reclamation and utilization of salinealkali soil.Plants vary in response to salt and alkali stresses,but salt stress has generally been the focus of numerous SAS studies.In addition,alkali stress is more severe than salt stress because of the accompanying high pH stress,which can inhibit uptake of ions and disrupt the ionic balance of cells.This article briefly describes the damage caused by these stresses and interprets the mechanisms in terms of the influences on biomass,photosynthesis,ion balance,and membrane permeability using a comprehensive summary of the advances in research on the physiological and biochemical responses to SAS.We focused on the alleviating mechanisms of plants under SAS with regard to selective ion absorption and pH balance,the synthesis of osmotic regulation substances,improvement of enzymatic antioxidant capacity,and the expression of genes relevant to SAS tolerance.Furthermore,this article proposes five ways to cope with SAS,including the addition of exogenous substances,synergistic effects of fungi,use of biotechnological tools,SAS acclimation,and breeding cultivars for SAS tolerance.Significant progress has been made using traditional methods to improve SAS tolerance,although genetic tools play a major role and comprise the direction of our further research as well.There is an urgent need to select SAStolerant varieties through biotechnological methods.The prospects for developing SAS tolerance are also discussed,with the aim of providing a reference for improving plant resistance to stresses and increasing crop yield.1) Although SAS limits crop growth and reduces agricultural productivity,it may also improve the quality of some fruits.It is,therefore,important to determine a balance between the yield and quality of plants.It is also necessary to determine the dominant factors in salt-alkali tolerance.Some indices have been frequently used in past studies,and a breakthrough in new indices is required.2)The differentially expressed proteins detected in plants have not been completely understood.The revelation of useful information related to SAS tolerance will lead to some unexpected discoveries.In the near future,it is important to increase the tolerance of plants to SAS by using genetic engineering technologies.The importance of genes in negative regulation needs to be considered.High throughput analysis of the differences in SAS tolerance between salt-tolerant plants and saltsensitive plants may aid in determining the root causes of the differences.More economic and ecological benefits can be achieved by cultivating additional SAS-tolerant plants and exploring the beneficial effect of saline-alkali tolerant plants on saline-alkali land that requires restoration and amelioration.These analyses also provided new insights into understanding the potential tolerance systems within plants.%盐碱胁迫是制约植物生长发育的主要非生物胁迫之一,也是制约农作物生产和生态环境建设的严峻问题.研究作物的耐盐碱机理,对开发和有效利用盐碱地有重要的现实意义.许多研究将盐碱胁迫笼统称为盐胁迫,实际上这是两种不同的非生物胁迫,且碱胁迫对植物的伤害要大于盐胁迫.总结性阐述了盐碱胁迫对植物的危害.从生物量、光合作用、离子平衡和膜透性等方面分析了植物对盐碱胁迫的响应机制,并结合最新研究从多角度综述了植物的抗盐碱机理,包括合成渗透调节物质、提高抗氧化酶活性、对离子的选择性吸收及pH平衡和诱导抗盐碱相关基因表达.提出了抗盐碱性的途径,即外源物质的加入、与真菌的协同效应、利用生物技术手段、培育耐盐碱品种和抗性锻炼.最后针对植物适应盐碱逆境方面的研究进行了展望,提出了当前研究需要解决的问题和突破口,旨在为提高植物耐盐碱能力、增加作物产量提供一定的理论依据.
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