【作者】 何华勤；

【导师】 林文雄；

【作者基本信息】 福建农林大学 ， 作物栽培学与耕作学， 2004， 博士

【摘要】 在农田杂草综合控制措施中，化感作用的应用将降低人类对化学农药的依赖程度，保护生态环境和人类健康。近年来，水稻化感作用的研究虽然取得较大的进展，但在生物测试方法、水稻化感物质、化感作用的遗传及基因定位方面尚有薄弱环节。为此，本研究首先采用两因子随机区组试验设计，比较分析了三种通用的生物测试方法对水稻化感作用潜力表现的效果。在此基础上，对来自10多个不同国家和地区的57份水稻品种进行化感作用潜力评价，并运用RAPD和ISSR技术分析水稻化感种质资源的遗传多态性。同时，分别采用色谱—质谱联用(GC-MS)技术和正交旋转回归设计分析水稻化感物质的产生与释放及其互作效应。最后运用功能蛋白组学和生物信息学技术探讨化感水稻抑草作用的分子机理。结果如下： 1、琼脂迟播共培法(RCA)与根系分泌物培养法(CRE)和石英砂迟播共培法(RCS)间存在极显著的差异。供试8个水稻品种在RCA中的平均抑制率为44.0％，其效果分别比CRS和RCS法增加86.4％和91.3％，说明RCA能较敏感地区别水稻品种间化感作用潜力的差异。 2、从57份水稻品种材料中获得5个化感作用潜力较强的品种，同时评价结果反映了品种间化感作用潜力的基因型差异。对化感水稻品种的RAPD和ISSR遗传多样性分析，结果发现地理位置相近的品种聚为一类。部分具有较强化感作用潜力的水稻品种亲缘关系很近，表明控制其化感作用性状的基因可能是等位的相同基因。而部分化感作用潜力差异显著的水稻品种聚为一类，这是由于人类在长期高产品种的定向选择过程中，水稻化感作用性状不被注意而丢失，遗传基础日益狭窄的原因。 3、在化感水稻叶和根的浸提液中检测到的酚酸类化合物比根系分泌物中的多，说明水稻体内产生的物质与释放出的物质存在明显的差异。水稻根系分泌物进入土壤后，部分物质会被土壤中的微生物分解或经过生物、非生物途径转化为其它物质。而且发现水稻品种间化感作用潜力的差异是由于其所产生的化感物质的差异以及物质间发生互作效应而引起的。 4、肉桂酸对抑制率的影响最显著，且其二次项系数为-6.18，达极显著水平。而香草酸对稗草根长抑制作用的效应曲线与另外4种酚酸物质的效应曲线不同，为开口向上的抛物线。在两因子互作效应分析中，因子间的增效或拮抗的互作效应取决与各因子在化合物中的浓度。当浓度水平较低时，两者间的作用效果是增效的，当浓度水平较高时，两物质间的作用效果是拮抗的。蜜内安5、在相同的环境条件下，化感水稻P13 12777叶片中的以L酶活性、总酚和类黄酮含 量都比Lemont中高，进一步表明了苯丙烷代谢是产生化感物质的重要途径之一。 在稗草胁迫下，化感水稻PI3 1 2777的叶片中以L活性表现出随着外界胁迫量的加 大而不断增强的趋势。而且总酚和类黄酮含量也提高，比Lemont叶片中总酚和类 黄酮含量的增加幅度显著得多。在本试验的4种密度的稗草胁迫下，水稻品种 PI3 12777叶片中总酚含量分别提高16.06%、21.98%、21.81%和16.81%，类黄 酮含量分别提高21.81%、27.53%、26.26%和21.64%。6、化感水稻P13 12777在稗草胁迫下的特异蛋白分别与苯丙氨酸氨解酶(PAL)、硫还原 型蛋白(Trx一m)、3一轻基一3一甲基戊二酞辅酶人还原酶(HMGR)和过氧化物酶(POO) 相匹配，其搜盖率分别为26%、18%、32%和26%.前三个蛋白催化或参与化感 水稻次生物质的代谢反应，促使水稻产生更多的化感物质。而过氧化物酶(沁O) 则是水稻细胞中的保护酶体系，保护细胞在环境胁迫下免受伤害。进一步对编码以 上特异蛋白的DNA序列进行分析，并在水稻的染色体上精确定位出化感作用相关 基因，确定出水稻化感作用的相关基因分别位于4、7、8和12条染色体上的克隆 位点.更多还原

【Abstract】 The application of allelopathy is an alternative weed control method that could be incorporated into an integrated weed management package, thereby reducing the dependence on herbicides and extending the commercial life of valuable chemicals. Progresses had made in rice allelopathy, but it is also possible to identify a range of researchable areas that still need attention, such as laboratory screening, the mechanism of allelopathy expression under environment stresses, identifying allelochemicals really responsible for weed reduction in the field, searching for the gene involving in rice allelopathy, etc.In this paper, the best bioassay methods was detected by comparing three laboratory screening methods for rice allelopathy, the genetic polymorphism of allelopathic rice was detected by using RAPD and ISSR, then allelochemicals in the leaf extraction and in exudation of rice accessions concerned were identified by GC-MS, at the same time, function proteomic approach was employed to analyze the molecular mechanism of allelopathy in rice induced by the stresses of accompanied weeds barnyargrass (Echinochloa crus-galli L.) .The results were summarized as follows:1 Relay co-cultured with agar (RCA) was significantly different from relay co-cultured with silica (RCS) and cultured with root-exudation (CRE). The average IR of concerned rice on barnyardgrass was 44.0% in RCA, being 91.3% and 86.4% higher than that in RCS and CRE respectively. If a rice accession showing high inhibitory activity on weed in RCA, its average IR in the three screening methods was high. Vice versa. It therefore suggested that RCA could effectively detect the distinct difference in allelopathic potential among rice cultivars tested.2 The considerable variations in allelopathic activity among 57 rice accessions introduced from 10 countries or areas were detected by RCA bioassay method, and five accessions strongly inhibiting the growth of barnyardgrass were characterized. The genetic polymorphism of allelopathic rice detected by RAPD and ISSR approaches indicated that those accessions from the same geographical location were clustered into one group. It was also found that some rice accessions with higher allelopathic potential were clustered together, implying that the genes conferring allelopathy in those rice accessions might be isolocus. However, some rice accessions with different allelopathic potential clustered into the same group performed lower level of generic polymorphism which was attributed to oriented selection for other traits in breeding program.3 The analysis on the substances related to allelopathy showed that the substances de novosynthesized in the tissue of rice were different from those released from rice roots. It was considered that substances released from rice might be decomposed by microbe or reacted biotically and abiotically with the soil prior to interacting with the target weeds. It was inferred that Lemont had lower allelopathic potential than PIS 12777 because of the absence of phenolic acids and the interaction among the substance in the exudation from rice roots.4 The different phenolic acids which were used in orthogonally gyral regression experiment had different impact on root growth inhibition of barnyardgrass. The cinnamic acid had strongly affected the growth of barnyardgrass, while the impact of vanillic acid on 1R was different from the other 4 phenolic acids. Whether the action of a mixture of phenolic acids is additive or antagonistic depends on the concentration of compounds in the mixture. At the low concentration level, the interaction of salicylic and cinnamic acid, salicylic and p-hydrobanzonic acid were additive. At the high level of concentration, the data generally supported the fact of antagonistic activities between them.5 The physiobiochemical mechanism of allelopathic rice under environment stresses was studied in this paper. The result indicated that the activity of PAL in the leaf of PI312777 displayed the trends of growing higher with the increasing of the更多还原