四种植物对土壤中莠灭净的积累和降解

发布时间：2018-10-05 19:05

【摘要】：莠灭净又名阿灭净,是由同为三嗪类化合物阿特拉津化学改性而得到的一种新型除草剂,它属于选择性、内吸传导型芽前芽后除草剂,目前已广泛用于玉米、马铃薯、甘蔗、香蕉、柑橘、菠萝等农田中来防除杂草。该农药性质稳定、持效期长,易贮存在土壤中,对植物正常生长、人类健康生活造成危害。因此,研究莠灭净在土壤中的降解行为意义重大。本文采用盆栽试验方法,以小麦、黑麦草、苜蓿和玉米为研究材料,以莠灭净为研究农药,比较研究了4种不同植物对土壤中莠灭净的积累和降解能力的差异。在莠灭净污染浓度为1mgkg-1的土壤中分别种植小麦、黑麦草、苜蓿和玉米,生长10d后,发现不同植物对土壤中莠灭净的吸收和降解能力不同,4种植物的地上部分中莠灭净的含量高于地下部分。其中小麦和苜蓿对莠灭净的积累量最大,黑麦草的传导因子(TF)最高为5.122。种植4种植物的土壤中莠灭净的残留量均低于未种植植物的空白土壤中莠灭净的残留量。培养10d后,空白土壤中莠灭净减少了 16.6%,而种植植物土壤中莠灭净则减少了 26.4%-50%,说明种植植物对土壤中莠灭净的降解具有一定的促进作用。根际土壤中莠灭净的残留量最少,相应减少了 41.1%-73.0%,原因可能与植物根际微生物群落与分泌物有关。黑麦草在莠灭净污染浓度为1 mg kg-1的土壤中生长10 d,黑麦草体内的过氧化氢酶、谷胱甘肽转移酶和漆酶酶活力升高。浓度为1 mg kg-1莠灭净对土壤中过氧化氢酶和脱氢酶的活力影响不大,对酚类氧化酶的活力有增强作用。污染土中种植4种植物后,土壤中过氧化氢酶和脱氢酶活力均明显升高,而酚类氧化酶活力下降。4种植物种植在污染或非污染土壤中,根际土壤中有机酸丙二酸、柠檬酸和苹果酸含量最高,而非根际土壤中含量最低。污染土壤中种植小麦和黑麦草时,土壤有机酸含量降低;种植苜蓿,有机酸含量升高;而种植玉米时,丙二酸和柠檬酸含量降低,苹果酸含量升高。说明土壤有机酸的变化受农药和种植植物的种类的共同影响。土壤酶活力和有机酸含量均是根际土混合土非根际土,这说明根系环境有利于莠灭净的降解。
[Abstract]:Herbicide, also known as Amijing, is a new herbicide obtained by chemical modification of triazine compound atrazine. It belongs to selective, internal absorption conduction herbicide after pre-bud herbicide. It has been widely used in maize, potato, sugarcane, etc. Weed control in fields such as bananas, citrus and pineapple. The pesticide is stable in nature and has long lasting effect. It is easy to be stored in soil, which is harmful to the normal growth of plants and the healthy life of human beings. Therefore, it is of great significance to study the degradation behavior of herbicide in soil. In this paper, using wheat, ryegrass, alfalfa and corn as research materials and herbicide as pesticide, the differences of accumulation and degradation ability of four different plants to soil herbicide were studied by pot experiment. Wheat, ryegrass, alfalfa and corn were grown in the soil with the net pollution concentration of 1mgkg-1 for 10 days. It was found that the absorption and degradation ability of different plants to soil herbicide was different. The content of herbicide in the aboveground part of four species of plants was higher than that in the underground part. Among them, wheat and alfalfa had the largest accumulation of herbicide, and ryegrass had the highest conduction factor (TF) of 5.122. The residual amount of herbicide in the soil planted with 4 kinds of plants was lower than that in the blank soil without planting plants. After 10 days of culture, the content of herbicide in blank soil decreased by 16.6m and that in planting plant soil decreased by 26.4-50, which indicated that planting plants could promote the degradation of herbicide in soil to some extent. The residue of herbicide in rhizosphere soil was the least, which decreased by 41.1-73.0. The reason may be related to the rhizosphere microbial community and secretion. The activities of catalase, glutathione transferase and laccase in ryegrass were increased after 10 days of growth in the soil with a net pollution concentration of 1 mg kg-1. The activity of catalase and dehydrogenase in soil was not affected by 1 mg kg-1 herbicide, but the activity of phenoloxidase was enhanced. The activities of catalase and dehydrogenase in polluted soil increased obviously, while the activity of phenoloxidase decreased in polluted or non-polluted soil, but in rhizosphere soil, the activity of catalase and dehydrogenase increased significantly, while the activity of phenoloxidase decreased in the rhizosphere soil. The content of citric acid and malic acid was the highest, but the lowest in non-rhizosphere soil. When wheat and ryegrass were planted in polluted soil, the content of organic acid decreased, while that of alfalfa increased, while that of malic acid and malic acid decreased. It shows that the change of soil organic acids is affected by pesticide and plant species. Both soil enzyme activity and organic acid content were non-rhizosphere soils in rhizosphere mixed soil, which indicated that root environment was beneficial to the degradation of herbicide.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173;X592

【参考文献】