【作者】 王丽；

【导师】 范志伟；

【作者基本信息】 海南大学 ， 农药学， 2012， 硕士

【摘要】 目前,随着环境压力、生态压力的不断增加,植物源除草剂越来越受到人们的重视。水田稗(Echinochloa oryzoides)是水稻(Oryza sativa)田的常见杂草,对水稻产量影响较大。本研究利用化感作用的原理,从21种植物中筛选出4种对水田稗种子萌发抑制较强的供体,评估它们化感作用的强弱,发现肿柄菊(TithoniadiversifoliaA.Gray)抑草活性最强。通过进一步对水田稗种子幼苗生长的抑制作用和移栽稻的安全性研究,发现肿柄菊鲜样地上部分在控制水稻田的水田稗杂草上最具研究价值。对其化感活性物质进行了分离,得到一化合物,并对其化感活性进行了研究。旨在为开发防除水田稗杂草的植物源除草剂奠定基础,同时也为天然除草剂的相关研究提供一定的资料。主要结果如下：1、采用种子萌发法,从12个科21种与水田稗同域或异域生长的海南常见植物中,筛选出12种对水田稗种子萌发具有较强化感活性的植物。再通过0.1g/mL、0.05g/mL、0.025g/mL和0.0125g/mL4个浓度的综合效应筛选出九里香(Murraya exotica)、银胶菊(parthenium hysterophorus)、黄蝉(Allemanda neriifolia Hook.)、肿柄菊4种植物具有较强的化感活性,对水田稗种子萌发抑制率较高,而对水稻种子萌发抑制相对较小。表明它们可以为水田稗种子萌发期的植物源除草剂的开发提供相关的理论依据。2、利用种子萌发法和幼苗生长试验法,研究不同肿柄菊水提液对黄瓜(Cucumis sativus)、鳢肠(Eclipta prostrata)、玉米(Zea mays)(?)口水田稗种子的萌发作用和幼苗生长作用,筛选出肿柄菊地上部分、茎和凋落物水浸液中含有防除水田稗的化感物质,且不同的肿柄菊水浸液对同一受体作用强弱不同,同一肿柄菊水浸液对不同的受体作用强弱也不同。表明肿柄菊可以通过化感作用来抑制其它植物的生长。3、利用盆栽实验法,评价肿柄菊的地上部分、茎和凋落物3个部分对移栽水稻生长的影响。主要通过测定各个处理对水稻的生物量、苗高的影响；水稻植物体内丙二醛(Malondialdehyde)、过氧化物酶(Peroxidase)、超氧化物歧化酶(Superoxide dismutase)含量的变化,水稻叶片叶绿素(chlorophyll)含量、类胡萝卜素(carotinoid)含量的变化,叶绿素荧光(Chlorophyll fluorescence)特性的变化,综合衡量各项指标,确定肿柄菊鲜样地上部分对移栽水稻的生长没有影响。4、采用活性追踪的方法,综合运用硅胶柱色谱法、薄层层析色谱法、SephadexLH-20柱色谱等多种色谱学分离手段,对肿柄菊地上部分干物质进行了研究,共分离得到1种化合物。通过分析化合物的理化性质、利用现代波谱学手段鉴定其化学结构为：肿柄菊内酯A(Tagitinin A)。5、测定肿柄菊内酯A对萝卜(Raphanus sativus)、黄瓜、水田稗、白菜(Brassica campestris Linn.)的幼苗生长试验。其抑制活性强弱表现为：水田稗>萝卜>黄瓜>白菜。更多还原

【Abstract】 Plant-derived herbicide has received much more attention with the increase in environmental and ecological pressure nowadays. Echinochloa oryzoides is a common weed in rice (Oryza sativa) cropland that significantly reduces its yields. This study screened out several plant species that can inhibit the germination of E. oryzoides seeds based on allelopathy, and evaluated their their allelopathic effects. Tithonia diversifolia was identified as the main plant species that has significant inhibitory effects. The study further examined the inhibitory effects on seedling growth of E. oryzoides and evaluated the security of transplanted rice, and found that the aboveground part of fresh T. diversifolia was the most valuable research target in controlling E. oryzoides in rice fields. Active allelopathic compounds were separated and one compound was obtained, with its allelopathic activity studied to establish a foundation for exploring plant-derived herbicide that could control E. oryzoides, and provide a reference for relevant research on natural herbicides.1. Twelve plants from21plants in12families that are common in Hainan were identified as useful in inhibiting seed germination of E. oryzoides based on allelopathy. Murraya exotica, Parthenium hysterophorus, and T. diversifolia were further identified that can have strong inhibitory effects on seed germination of E. oryzoides but little effects on seed germination of rice based on integrative effects of four concentration. These suggest that the three plant species have the potential to be explored as plant-derived herbicides that can inhibit E. oryzoides during their germination period.2. Effects of water extracts from T. diversifolia on seed germination and seedling growth of Cucumis sativus, Raphanus sativus, Zea mays, and E. oryzoides were studied. Allelopathic substances that can control E. oryzoides were screened out from water extracts of the aboveground part, stems and litter of T. diversifolia. Effects from different water extracts were various on the same target, and effects of the same water extracts were various on different targets. T. diversifolia could inhibit the growth of other crops through allelopathy.3. Effects of water extracts from aboveground part, stems and litter of T. diversifolia on the growth of transplanted rice plants were evaluated through pot experiments. After integrated weighing of indices such as biomass, seedling height, malondialdehyde content, peroxidase enzyme, superoxide dismutase enzyme, leaf chlorophyll content, carotinoid content, and chlorophyll fluorescence content of rice plants, this study confirmed that aboveground part of T. diversifolia could stimulate the growth of transplanted rice plants.4. Organic solvents such as95%ethanol, petroleum aeher, chloroform, ethyl acetate, and btanol were used to extract aboveground part of T. diversifolia through the activity tracking method, and gel and silica gel chromatography methods were used to isolate and purify compounds. One allelochemical was isolated from the aboveground part of T. diversifolia. Spectral analyses such as mass spectrum and nuclear magnetic resonance were used to identify the compound, and it was tagitinin A.5. Effects of tagitinin A on seedling growth of R. sativus, C. sativus, E. oryzoides, and Brassica campestris Linn. were measured, and the strength of inhibition increased from B. campestris, C. sativus, R. sativus, to E. oryzoides.更多还原