甜菜对盐碱胁迫的适应性机制及其调控技术研究

In the past, we focused on the research under neutral salt and paid more attention to the research on aboveground part of sugar beet, but neglected the research about basic salt and the underground part of sugar beet. Moreover, most studies that we did were on seedlings under water culture experiment and could not be combined with field production. In order to overcome the above shortcomings, pot experiment was designed with different saline environments and alkali environments for studying the adaptability of different genotypes of sugar beet to saline-alkali stress and grading saline-alkali tolerance to provide reference for production. We will study the change of root exudate ,the rhizosphere effect,cell biology identification, physiological response and excavating saline-alkali tolerance gene of sugar beet under saline-alkali stress. The mechanism of adaptability to saline-alkali stress was revealed from the aspects of morphology, cell, physiology and molecular. The regulation techniques of exogenous substances were explored .These researches provide theoretical basis for further discussing the pathways of improving saline-alkali Our research will provide important science value for enriching sugarbeet physiological theory, for the exploitation and utilization of saline-alkali land in North of China, especially in Songnen Plain, for solving the contradiction of competing for land between cash crop and grain crop, for enlarging sugarbeet planting area and for promoting the development of sugar-manufacturing industry. The prospect of our study is promising.

为克服以往甜菜研究只注重中性盐忽视碱性盐、注重地上部分忽视地下部分研究、注重苗期水培研究忽视与生产实践结合的缺点，利用盆栽模拟不同程度的盐碱环境，研究不同基因型甜菜对盐、碱胁迫适应程度阈值，对其做出排序和耐盐碱的分级，为生产提供参考；通过盐碱胁迫下根际分泌物的变化分析，根际效应研究，根系的细胞生物学鉴定及生理响应和耐盐碱基因的挖掘筛选，从形态、细胞、生理和分子等层面揭示甜菜对盐碱胁迫的适应性机制。通过外源物质调控，探讨提高耐盐碱程度的调控技术。这些研究为进一步提高甜菜耐盐碱性提供理论依据。对丰富甜菜生理的基础理论具有重要的科学价值，对北方尤其对黑龙江松嫩平原大面积盐碱土的开发和利用，解决经济作物与粮食作物争地的矛盾，扩大甜菜种植面积，促进制糖产业的发展，具有广阔的前景。

甜菜是世界上两大糖料作物之一，又是中国三北地区重要的经济作物，有较强的耐盐碱特性，对盐碱土的开发和利用具有强大的发展潜力。因此，研究其耐盐碱的适应性机制和调控途径具有重要意义。为克服以往甜菜研究只注重中性盐忽视碱性盐、注重地上部分忽视地下部分研究、注重苗期水培研究忽视与生产实践结合的弊端，通过水培与土培相结合试验，在不同程度的盐、碱胁迫下，从形态、细胞、生理和分子等层面揭示甜菜对盐、碱胁迫的适应性机制及其外源物质调控的方法。结果表明，甜菜对中性盐（NaCl与Na2SO4混合）耐受程度排序为：糖用、饲用和食用，幼苗对中性盐胁迫的适应范围较宽，约为0.3%；对碱性盐（NaHCO3与Na2CO3混合）耐受排序为：食用、糖用和饲用，胁迫因子主要是pH值，对pH值的适应范围为8-9。为适应碱胁迫， 体内多胺和有机酸含量增加，同时根系分泌物种类减少，揭示甜菜体内有机酸和多胺对适应碱胁迫的调节作用；进一步阐明了渗透调节和根系对Na+的离子区域化是甜菜适应胁迫的主要方式，渗透调节程度甜菜碱最大、可溶性糖和脯氨酸次之；叶绿体中嗜锇颗粒増多对适应碱胁迫有积极的作用；阐释了响应碱胁迫的lncRNA的靶基因主要涉及信号转导、能量摄入与利用、分子代谢、植物自身解毒作用以及基因的转录和翻译等过程，鉴定出甜菜的268个已知miRNA；阐明盐胁迫后甜菜通过调节碳氮代谢以适应环境的机理，揭示根系适应盐胁迫尿囊素大量积累的重要途径，找到其关键基因。阐明了生物炭通过调节土壤理化性质、微生物多态性和养分平衡来缓解盐碱胁迫和减少氮肥施用的作用效果，揭示外源BR提高甜菜盐碱适应性的调控效应及其响应机理，明确了适宜的使用时期，为进一步提高耐盐碱途径提供理论依据和参考。上述结果对丰富甜菜逆境生理的基础理论具有重要的科学价值，对松嫩平原大面积盐碱土的开发和利用，解决经济作物与粮食作物争地的矛盾，扩大甜菜种植面积，促进制糖产业的发展，具有广阔的前景。