CO2加富环境下亚精胺调控番茄抗盐性的水分代谢机制

CO2 deficiency and soil secondary salinization are the important bottlenecks in the sustainable development of protected agriculture in our country. CO2 enrichment is used to accompany with the soil salinization to excavate the yield potential of crops. However, the research in combining CO2 enrichment and plant salt tolerance are scarce. Application of exogenous spermidine (Spd) can effectively alleviate the salt damages, but the molecular regulation mechanism of Spd on the water metabolism in this situation has not been explored yet. In this project, tomato cultivar ‘Zhongza No.9’ is used as experimental material, and Ca(NO3)2 is used to simulate the protected agriculture salinity. The underlying rules of the root and aboveground water changing in tomato will be systematically analyzed. It is helpful to get better understanding the role of water metabolism in the exogenous Spd-induced salt tolerance of tomato under CO2 enrichment. The temporal and spatial expression patterns of different tomato PIP genes will be detected by means of real-time RT-PCR. Moreover, the temporal and spatial change features of membrane integrity and lipid peroxidation, reactive oxygen species accumulation, antioxidant enzymes activities and related gene expression in tomato will be investigated. Those indices will help to reveal the Spd-mediated interaction of redox signaling and water metabolism under CO2 enrichment and salt stress. The present study aims to clarify the water-driven mechanism in the Spd-regulated resistance of tomato to salt stress under elevated CO2 condition, and to explore a new way in the anti-salt and high-efficiency cultivation of protected vegetables.

CO2亏缺和土壤次生盐渍化是制约我国设施农业可持续发展的重要瓶颈。为了挖掘作物的增产潜力，生产中往往在设施土壤盐渍化的同时进行CO2施肥，但基于CO2加富和盐胁迫互作的相关研究较少。通过使用外源亚精胺（Spd）可有效缓解盐害效应，但盐胁迫下Spd对植物水分代谢的分子调控机制尚未明确。本项目拟以‘中杂9号’番茄为试材，以Ca(NO3)2模拟设施土壤盐渍化，分析番茄根系和地上部水分特性的变化规律，明确CO2加富环境下水分代谢在外源Spd诱导番茄抗盐性中的作用；通过检测不同种类PIPs基因的时空表达模式，并结合质膜完整性、膜脂过氧化程度、活性氧积累水平、抗氧化酶活性和基因表达的时空变化特征分析，揭示CO2加富和盐胁迫下Spd介导的redox信号与水分代谢之间的关系。本研究可望阐明CO2加富环境下Spd调控番茄抗盐性的水分驱动机制，探索一条基于外源Spd和CO2施肥的设施蔬菜抗盐高效栽培的新途径。

土壤次生盐渍化是制约设施作物生产的重要瓶颈，Ca2+和NO3-是设施盐渍化土壤的主要成分，国内外关于作物耐盐性的研究多集中于NaCl 胁迫，不能准确反映设施土壤次生盐渍化对作物的伤害机理。设施生产中往往在土壤次生盐渍化的同时进行CO2施肥，通过使用外源亚精胺（Spd）可有效缓解盐胁迫伤害，但CO2加富与Spd的互作效应及其对作物等渗盐胁迫抗性的调控模式尚未明确。本项目以‘中杂9号’番茄为试材，采用盆栽法和水培法，以150 mM NaCl和100 mM Ca(NO3)2模拟等渗盐胁迫环境，以800 ppm CO2模拟CO2加富环境，通过外源喷施0.25 mM Spd处理，探讨了不同处理互作对番茄植株生长、光合特性、水分特性、抗氧化系统、渗透调节系统、主要矿质元素含量、关键酶基因表达特性、信号转导等的影响，并开展了差异蛋白质组学研究。初步结果表明，等渗盐胁迫下，番茄植株生长受到抑制，相对质膜透性、丙二醛和活性氧积累水平显著增加，根系活力、光合作用、水分和养分的吸收能力下降，且NaCl胁迫的抑制效应明显大于Ca(NO3)2胁迫，CO2加富或外源Spd处理可通过减少过量活性氧的产生、提高抗氧化防御和渗透调节能力、改善植株的水分和养分状况等多个生理过程来缓解等渗盐胁迫对番茄植株的抑制效应，且两者的调控效应表现为一定程度的正协同性。本项目通过探讨CO2加富下外源Spd调控番茄等渗盐胁迫抗性的作用机制，可望为设施作物抗盐栽培提供理论依据，具有重要的理论价值与实践意义。