【作者】 袁莉；

【导师】 于磊；

【作者基本信息】 石河子大学 ， 动物营养与饲料科学， 2008， 硕士

【摘要】 本论文通过以下5个试验就苜蓿自毒性特征及其对农作物的他感影响开展研究。试验一:分别将采集石河子大学牧草实验地第二年苜蓿（品种为三得利）的地上部分和根分别三等分,研究各个部位的自毒性特征,试验结果表明,苜蓿不同部位提取液对苜蓿种子萌发表现出不同的自毒作用。苜蓿地上部分浸提液对种子萌发的抑制作用大于根部各部分,这可能是由于苜蓿的自毒物质地上部分的含量大于地下部分。此外,苜蓿的自毒作用呈现出明显的浓度效应。试验二:于2007年4月14日在石河子大学牧草学实验地播种苜蓿（品种为三得利）,分别在新生苗期、分枝期、孕蕾期、初花期、结荚期采样研究其各生育期的自毒性特征。研究结果表明:新生苜蓿的茎叶提取液对其种子存在自毒作用,当提取液的浓度相同时,不同生育期的浸提液对苜蓿的自毒作用不同,当提取液的浓度为0.1 gDWml^-1时,各生育期浸提液的自毒作用（根据化感综合效应指数反应的结果）由强到弱的排列顺序位为:结荚期>初花期>孕蕾期>分枝期>苗期。苜蓿的自毒作用随着生育期的进行而增强.试验三通过对生长2、3、4年苜蓿的茎叶、根进行采样,制作浸提液。用浸提液处理棉花、玉米、小麦及苜蓿种子用生物测定的方法测得被处理种子的发芽率、幼苗胚根长度、单个苗干重。试验结果表明:苜蓿浸提液对苜蓿、小麦、玉米和棉花存在化感作用,从各个表里的化感综合效应指数可看出,当提取液的浓度为0.025 gDWml^-1时处理棉花、苜蓿、小麦、玉米时,苜蓿茎叶提取液对这些作物的抑制作用大于苜蓿根部提取液;对这些作物的化感作用由强到弱的顺序为:棉花>苜蓿>小麦>玉米,其中,苜蓿茎叶和根部提取液对玉米的化感综合效应指数均大于零,即促进作用,因此,从化感的角度考虑,与苜蓿轮作的最适作物为玉米。试验四:在生长第四年苜蓿田里采集土样,将土样放置不同时间后播置棉花、玉米、小麦及苜蓿种子,测定苗高,发芽率及苗干重。试验结果表明:种植过苜蓿的土壤放置土壤放置0周到5周,这些处理对苜蓿、棉花、小麦和玉米化感综合效应指数分别为:在3.43%至110%之间、-6.39%-35.13%、13.29%-82.13%之间和21.07%-53.96%之间,由此可以得出:这些处理对上述作物的影响由高到低的排列为:苜蓿>玉米>小麦>棉花。试验五:用高效液相色谱（HPLC）法测定了苜蓿各个生育期、不同年限苜蓿以及各个土样里咖啡酸、羟基苯甲酸、香豆酸及绿原酸的含量。研究结果表明苜蓿茎叶部位的这四种酚酸含量高于根部的,且第三年苜蓿茎叶提取液里酚酸含量最高,由高到低的排列顺序为:生长第三年苜蓿茎叶>生长第四年苜蓿茎叶>生长第二年苜蓿茎叶>生长第二年苜蓿根>生长第四年苜蓿根>生长第三年苜蓿根。新生苜蓿植株体内的四种酚酸的含量在不同生育期由高到低的排列顺序为:结荚期浸提液>初花期浸提液>孕蕾期的浸提液>分枝期的浸提液>苗期的浸提液。从测试结果可以得出:苜蓿体内的化感物质积累随着生育期的延续而增加,且化感物质的含量在成熟植株体内含量高。土壤里的酚酸含量随着放置时间的延长而降低,放置5周后,羟基苯甲酸和咖啡酸含量极低或为零,说明通过放置的方法可以降低土壤里化感物质的含量,且放置5周后土壤里的化感物质降到极低。更多还原

【Abstract】 Five experiments were conducted to research and develop character of Alfalfa’s autotoxicity and its allelpathy effects on several crops.Experiment 1. Alfalfa’s leaves and roots were collected in grassland science experiment field, in Shihezi university ,then were devided into three parts average to research their autotoxicity.The result shows that the different aqueous extracts from the alfalfa had different autotoxicity on its seed germination .The concentration of aqueous extracts’inhibition from the top parts of alfalfa is much stronger than its roots’. Maybe this because autotoxicitic compounds are concentried on its leaves and stem. What’s more, alfalfa’s autotoxicity is relevant to the concentration of different aqueous extracts .Experiment.2 Alfalfa(Sandeti) was seeded in grassland science experiment field on 14 April ,2007. Alfalfa’s leaves and stem were collected in their different growing stages to research their autotoxicity. The result shows that aqueous extracts from the new alfalfa had autotoxicity on its seed germination.When the concentration of aqueous is 0.1,The blooming stage and the fruiting stage showed significantly stronger allelpathy than the budding stage, the branching stage, and the seeding stage . The autotoxicity gathers head with growing stagesExperiment.3.2-year-old,3-year-old and 4-year-old alfalfa’s leaves and stem, roots were collected then were made into aqueous,Treating cotton ,corn,wheat ,and alfalfa seeds with the aqueous, seeding germination, young radicel and dry weight of young plant of each seed is tested by bioassay.The result showed that the aqueous had autotoxicity on cotton ,corn,wheat ,and alfalfa .Seeing the synthesis exponent of allelpathy on the table, when the concentration of aqueous is 0.025,treating cotton ,corn,wheat ,and alfalfa seeds with the aqueous,the cotton was showed significantly stronger allelpathy than alfalfa, wheat, corn. synthesis exponent of allelpathy on corn is above zero,it boosts corn growing.So corn is the best crop to rotate with alfalfa considering allelpathy.Experiment4.Siol was collected in 4-year alfalfa field,and was placed for different weeks Cotton ,corn,wheat ,and alfalfa were planted in the soil.The seeding length, seeding germination dry weight of young plant of each seed were tested by bioassay. The result showed that treating alfalfa ,cotton , wheat , and corn seeds with the soil, in turn synthesis exponent of allelpathy on them is from 3.43% to110%,from minus 6.39% to minus 35.13%, from 21.07% to53.96%, from 13.29% to 82.13%.A result is also adduced that the effect on alfalfa is stronger than corn ,wheat and cotton.Experiment5 Caffeic acid,P-hydroxybenzoic acid, chlorogenic acid and p-coumaric content of the alfalfa’s aqueous extracts from different growing stages, 2-year-old,3-year-old and 4-year-old alfalfa’s leaves and stem, root and soil placed different weeks were analyzed with HPLC.The result showed that the four phenolic acids content of alfalfa’s leaves and stem is higher than its root, and the four phenolic acids content of 3-year-old alfalfa’s leaves and stem is the highest,then 4-year-old alfalfa’s leaves and stem,the third is 2-year-old alfalfa’s leaves and stem,the fourth is 2-year-old alfalfa’s root,then is 4-year-old alfalfa’s root ,the last one is 3-year-old alfalfa’s rootThe four phenolic acids content of new alfalfa’s leaves and stem in fruiting stage is significantly stronger than the blooming stage the budding stage, the branching stage, and the seeding stage .A result can be gained that allelpathy of alfalfa is increasing with growing stages and the content of allelpathy is much higher in mature plants.The four phenolic acids content of soil falls with delaying placed soil, after 5weeks caffeic acid,P-hydroxybenzoic acid content of soil falls the lowest,that is to say, The four phenolic acids content of soil can be fallen by this way .更多还原