紫茎泽兰叶片水提液对鸭茅种子发芽、幼苗生长及保护酶的影响

对紫茎泽兰(Ageratina adenophora Sprengel)化感作用的研究有很多，但化感物质以土壤为媒介对与之竞争的本地植物的影响以及本地植物自身的反应机理还知之甚少。以具有较强竞争力的优质牧草鸭茅(Dactlis gloerata L.)为材料，利用改进的培养皿滤纸法测定了紫茎泽兰叶片水提液对鸭茅种子相对发芽率、发芽时间的影响，研究了幼苗株高、生物量及保护酶（SOD、POD和CAT）活性的时间动态。紫茎泽兰叶片水提液对鸭茅种子发芽和幼苗生长均有化感作用，不同浓度的水提液对受体植物的化感作用强度不同。在5%高浓度处理下鸭茅种子发芽率显著降低；2.5%和5%两个浓度处理则使种子的发芽时间明显滞后。处理初期，高浓度水提液处理下的幼苗高度和生物量较低，但随着时间延长，各处理间逐渐差异减小，第20天时，各浓度处理间无显著性差异。水提液对鸭茅体内保护酶活性影响显著。其中在低浓度处理下，随着处理时间的延长POD活性波动较小，CAT活性则波动较大；相反，高浓度处理下POD活性波动较大，CAT活性则波动较小；在处理初期，各处理间的SOD活性差异较为显著，第20天时，各浓度处理间无显著性差异，与株高和生物量变化趋势相符。以土壤为媒介时，鸭茅幼苗表现为对紫茎泽兰的水提液的化感作用不敏感，说明其潜在的替代控制紫茎泽兰的能力，对于紫茎泽兰的替代控制提供了一定的指导。

Effects of aqueous leaf extract of Ageratina adenophora Sprengel on seed germination, seedling growth and antioxidative enzymes of Dactlis gloerata

Allelopathy plays an important role in successful invasion of croflon weed Eupatorium adenophorum Spreng. and a large quantity of related studies have been reported. However, the study on the relationship between E. adenophorum＇ s allelochemicals and native plants in the medium of soil was quite limited. In this study, the effects of aqueous leaf extract of E. adenophorum on germination rate （GR） and germination time （GT） of Dactlis gloerata were determined with different concentrations of extract via the modified filter paper - petri dish method. Besides, the changes in seedling growth and the activities of antioxidative enzymes of D. gloerata were measured in early growth stages. The results showed that the GR of D. gloerata was significantly
affected by high concentration of the extract. Seedling height （SH） and seedling weight （SW） decreased significantly with the increased concentration treatments in the early stages. The differences of SH and SW in various concentration treatments were not significant in the late stages. The activities of antioxidative enzymes varied significantly among different treatments. At the lower concentrations, the activity of POD varied little among different treatment periods, but the activity of CAT varied remarkably. In contrast, at the higher concentrations, the activity of POD varied obviously, and the activity of CAT varied little. At the beginning of the treatment, the activity of SOD varied significantly, but no significant difference existed at the 20 d treatment. The results of this study have provided some theoretical guidance for replacement control of E. adenophorum.