甜菜根系分泌物对大豆的化感作用及其基因表达谱分析

Sugar beets are grown in a hydroponic system, and root exudates are collected and separated at both seedling stage and root growth stage. Bioassay of allelopathy is tested for soybean, and gas chromatography-mass spectrometry (GC-MS) is used to identify the allelochemicals. A pot experiment is set up, in which sugar beets and soybeans are grown separately in different pots, grown in the same pot, and grown in the same pot but the roots of sugar beet are confined in a smaller container using soil with or without sterization in both rotational cropping and continuous cropping system, to test photosynthetic indexes, and verify allelopathic effect. Also, a field experiment, in which soybeans are grown following sugar beets and intercropped with sugar beets in a rotational cropping system, is carried out, and denaturing gradient gel electrophoresis (DGGE) technology is used to analyze the soil microbial flora, quantity its changes and verify the allelopathy from the point of view of interaction of root exudates with soil microbes. Using the receptor leaf with the allelopathy effect in the bioassay as the test material and applying gene chip technology, the gene expression mapping of expression gene relevant to the sugar beet allelopathy and its molecular regulation are analyzed, important relative gene and function are cloned and identified, and the synergy mechanism of multiple genes involved in the alleloparthy is preliminarily clarified. This research will lay down a theoretical basis in allelopathy field for establishing crop rotation system and cultivation system involving sugar beet and have significant implication for sustainable development of sugar beet industry and ensuring national sugar safety. This research also has great academic value for enriching the theory of sugar beet allelopathy, clarifying preliminarily the relationship between "resource competition" and "allelopathy" , which is a focus of debate worldwide, and exploring the molecular mechanism, which may facilitate further in-depth allelopathy research. Only in Heilongjiang province, 133,333 hectares of sugar beets are planted, and application of the research, therefore, will have bright future.

收集、分离水培甜菜童、叟期根系分泌物，生物检测对大豆化感作用潜力，GC-MS鉴定化感物质；设甜菜正茬土与重茬土灭菌与否的甜菜和大豆单栽、混栽与合栽但地下根部分离的盆栽试验，测光合参数等，验证化感效应；设甜菜前茬的大豆清种、正茬甜菜间作大豆的田间试验，DGGE技术分析土壤微生物菌群及数量变化，从根系分泌物与土壤微生物互作角度探究化感作用；以化感受体水培大豆叶片为试材，采用基因芯片技术，对与甜菜化感作用及其分子调控相关的表达基因进行表达谱分析、克隆鉴定重要相关基因与功能、初步阐明化感作用中多基因的协同作用机制。 本研究为建立包括甜菜在内的作物轮作体系和耕作制度提供化感领域理论依据，对甜菜产业可持续发展、保障食糖安全具有重要意义；填补甜菜化感基础性资料、初步明晰一直处于国际争论焦点的"资源竞争"与"化感作用"关系问题、分子机制探讨具有很高学术价值；仅黑龙江省种植200万亩甜菜，应用前景广阔。

..采用1/2Hogland营养液培养标准型甜菜中甜207幼苗，以50ml去离子水收集的幼苗期根系分泌物溶液为基准浓度（H）溶液，再以添加去离机水的方法配制成Ｈ、1/2Ｈ、1/4Ｈ、1/8H浓度的甜菜根系分泌物。测定各浓度甜菜根系分泌物对大豆东农42种子发芽势、发芽率的化感潜力。采用甜菜中甜207和大豆东农42分别单栽、混栽与合栽但两作物根系分离的双套筒框栽试验，研究甜菜根系分泌物对大豆的化感作用。结果表明：.1.甜菜根系分泌物对大豆种子萌发有抑制方向的化感作用，1/8H、1/4H、1/2H、H浓度对发芽势的化感潜力分别达-15.79%、-17.89%、-18.95%和-31.58%；对发芽率的化感潜力分别达-15.79%、-25.26%、-31.58%和-36.84%，抑制性化感潜力随根系分泌物浓度的增加而增大。 .2.甜菜对大豆的生长发育有明显的抑制性化感作用。对大豆株高、每株节数、每株荚数、每荚粒数、每株粒数、百粒重、单株籽粒产量和生物产量性状的化感作用潜力平均值为-0.0869。.3.存在甜菜与大豆争夺地下部资源的竞争作用。在大豆株高、每株节数、每株荚数、每荚粒数、每株粒数、百粒重、单株籽粒产量和生物产量性状上竞争潜力平均值为-0.0193。.4.当季土壤微生物在甜菜对大豆抑制性化感作用中有抵消作用。土壤微生物对大豆的作用潜力平均值为0.0273。.5.甜菜对大豆的化感作用是负效应，甜菜对大豆的地下资源争夺是负效应，当季土壤微生物对大豆的生长发育是正效应，它们的作用大小是甜菜的化感作用潜力8.69%>当季土壤微生物抵消作用潜力2.73%>甜菜对大豆的地下资源竞争潜力1.93%。.6.验证了甜菜对大豆化感作用的生理效应和土壤酶活性的响应。.