甜菜耐盐种质资源发掘及渗透调节机制研究

Research content: ① Screening, Innovating and excavating higher salt resistance germplasm resources of sugar beet; ②Analysising salt ions absorbed and accommodated by sugar beet and osmotic adjustment content and distribution in sugar beet, studying salt ions separated and osmotic adjustment content and differences in different parts in salt tolerance and salt sensitive sugar beet in salt stress, analysising the role and contribution to salt tolerance regulation of any kind of osmotic adjustment. ③ Studying the effect of applying of exogenous osmotic to sugar beet on improving salt tolerance and physiological and biochemical parameters in the salt stress, determining the main osmotic adjustment substances for salt resistance in sugar beet; ④Analysising and identificating to specific or different proteins between normal and salt stress or salt-tolerant and salt sensitive sugar beet germplasm in the salt stress, and understanding the salt ions absorbed/ accommodated mechanism, osmotic regulation mechanism and other mechanisms of salt tolerance of sugar beet from proteins molecular level. Significance: Excavating sugar beet germplasm resources for salt tolerance, figuring out absorbing salt ions and osmotic adjustment regulation mechanism from different salt tolerance sugar beet materials, it can improve and perfect plant salt tolerance theory. Excavating and using sugar beet excellent salt tolerance gene resources, analysising and identificating to specific or different proteins between salt-tolerant and salt-sensitive sugar beet germplasm,it can lay foundation for sugar beet breeding and molecular biology research, also provide theoretical basis for developed cultivation measures. Sugar beet is sugar material and energy crop, application of salt-tolerant varieties prospects broad in saline-alkali soil, and have higher economic and social benefit.

研究内容：①鉴定、筛选并发掘高度耐盐甜菜种质资源材料；②分析甜菜吸纳盐分离子与渗透调节物质含量和分布规律，在盐胁迫及半致死盐胁迫下研究盐分离子隔室化和渗透调节物质含量的基因型差异，分析各种渗透调节物质的作用与贡献率。③研究预先施用主要外源渗透调节物质对提高甜菜耐盐性及促进甜菜抗盐胁迫的生理生化指标作用，确定增强甜菜耐盐作用的主要渗透调节物质；④分析与鉴定盐胁迫与耐盐性甜菜种质的特异或差异蛋白，从蛋白质分子水平揭示甜菜吸纳盐分离子与渗透调节机制及其它耐盐机制。意义：发掘甜菜耐盐种质资源，摸清耐盐性不同甜菜种质资源材料吸纳盐分离子以及渗透调节机制，可完善植物耐盐理论；挖掘与利用甜菜耐盐优异基因资源，分析鉴定盐胁迫与耐盐性甜菜种质的特异或差异蛋白，可为甜菜育种和分子生物学研究奠定基础，也为制定栽培措施提供理论依据；甜菜是糖料和能源作物，盐碱地上耐盐品种应用前景广阔，经济和社会效益都较高。

利用耐盐碱植物高效利用盐碱地有着重大意义。本项目主要研究内容耐盐甜菜种质资源发掘，甜菜盐分离子与渗透调节物质在甜菜体内分布、含量以及对甜菜适应盐胁迫的生理作用研究，外源甜菜碱对甜菜适应盐胁迫的作用，盐胁迫下甜菜特异或差异蛋白分析与鉴定。结果表明，筛选耐盐甜菜种质资源32份，通过组培挖掘1份甜菜耐盐突变体。明确氯化钠胁迫下幼苗盐分离子在甜菜体内分布、含量差异。甜菜体内渗透调节物质含量提高来适应盐胁迫，其作用大小顺序为：甜菜碱>氨基酸>苹果酸>丁二酸>蔗糖>柠檬酸>丙酮酸>还原糖>胆碱>富马酸，耐盐甜菜品系更明显。盐胁迫导致甜菜气孔导度、蒸腾速率、胞间二氧化碳浓度、净光和速率，Hill反应、RuBPcase活力，PEPC活性、MDH活性显著下降，耐盐品系表现优于盐敏感品系；导致叶片水势、相对含水量显著下降，叶片电导率和MDA含量均呈显著上升趋势，加重质膜伤害；使叶片SOD、GPX、CAT以及APX酶活性均明显升高以减轻质膜伤害，其中SOD和APX酶活性上升幅度较大，耐盐品系更明显；甜菜根、叶柄和叶中氮素和钾素含量均显著降低，全磷含量则有不同程度提高；甜菜叶片ABA含量明显提高，老叶ABA含量较高；IAA及GA3含量显著降低，老叶IAA、GA3含量较低，耐盐品系与盐敏感品系比较ABA含量低、IAA、GA3含量高。NaCl0.6 和0.8mol/L胁迫下，盐分离子含量继续升高，有机渗透调节物质含量降低，甜菜仍可以正常完成生育周期。外源甜菜碱明显提高幼苗生物量、甜菜碱含量以及过氧化物酶、过氧化氢酶、超氧化物歧化酶、叶绿体偶联的ATPase活性、光合作用等，但是叶片丙二醛含量和相对电导率均降低。NaCl胁迫蛋白质组学差异研究表明，盐胁迫抗氧化酶类相关蛋白、ATP酶相关蛋白、甜菜碱相关蛋白的差异表达与可溶性蛋白含量、质膜透性、MDA含量、抗氧化酶类活性、ATP酶活性、甜菜碱含量提高相互印证。磷酸烯醇式丙酮酸羧化酶家族蛋白表达量上升与该酶活性升高（中度胁迫）或轻度降低（高度胁迫）相互印证。