Abstract: In order to explore the effects of potassium application on the life parameters of Acyrthosiphon pisum on alfalfa， Medicago sativa ‘Gannong No.3’ was used as an experimental material. Four potassium applications were set， wthich were K₀（0 mg·kg^-1），K₁（30 mg·kg^-1），K₂（60 mg·kg^-1），K₃（90 mg·kg^-1） and no fertilization was set as a control （CK）. At the 6-leaf stage of alfalfa， A. pisum was fed with the 3rd leaf from the top of alfalfa. The growth， development and reproduction of A. pisum were recorded and calculated under different potassium applications. Simultaneously， the nutrients and total polyphenols in the 3rd leaf from the top of alfalfa plants were measured. The result showed that the development period of nymphs was prolonged markedly under the medium potassium treatment （K₂）and CK treatment compared to the other treatments （P<0.05）. The net reproduction rate， intrinsic rate of increase， and finite rate of increase of adult A. pisum were lower significantly under K₂ treatment than those of the other treatments （P<0.05）. The soluble sugar content， total phenol content and carbon-to-nitrogen ratio in alfalfa leaves under K₂ treatment were significantly higher than those of the other fertilized applications （P<0.05）. The soluble protein content in alfalfa leaves under K₃ treatment increased significantly （P<0.05）. The correlation analysis indicated that the survival rate， the average daily aphid production per female and the intrinsic growth rate of A. pisum were negatively correlated with the soluble sugar content and the total phenol content of alfalfa leaves significantly. The average daily aphid production per female and the intrinsic growth rate of A. pisum were positively correlated with the soluble protein content. A positive correlation existed between the finite rate of increase and the soluble protein content significantly.The potassium fertilizer increased the ratio of carbon to nitrogen and the content of secondary metabolite in alfalfa leaf， thereby inhibiting the growth， development and fecundity of A. pisum.

Key words: Medicago sativa, Potassium fertilizer, Acyrthosiphon pisum, Life parameter, Antibiosis

摘要： 为了揭示施钾苜蓿对豌豆蚜（Acyrthosiphon pisum）生命参数的影响，本研究以‘甘农3号’紫花苜蓿（Medicago sativa）为材料，设置4个施钾处理[K₀（0 mg·kg^-1）、K₁（30 mg·kg^-1）、K₂（60 mg·kg^-1）和K₃（90 mg·kg^-1）]，并设1个完全不施肥为对照（CK），在苜蓿6叶期，用倒3叶饲喂豌豆蚜，记录其生长发育、繁殖情况，并测定苜蓿倒3叶中的营养成分和总酚含量。结果表明， K₂和CK处理下豌豆蚜若虫的发育历期显著延长，K₂处理下若虫的存活率、成虫繁殖力、净增殖率、内禀增长率和周限增长率均显著降低（P<0.05）。K₂处理下苜蓿叶中可溶性糖、总酚含量和碳氮比最高，K₃处理下可溶性蛋白含量最高（P<0.05）。豌豆蚜的存活率、单雌日均产蚜率和内禀增长率与可溶性糖和总酚含量显著负相关；单雌日均产蚜率和内禀增长率与可溶性蛋白含量极显著正相关；周限增长率与可溶性蛋白含量呈显著正相关。施钾提高了苜蓿叶片中的碳氮比和次生代谢物质含量，进而抑制了豌豆蚜的生长发育和繁殖力。

关键词: 苜蓿, 钾肥, 豌豆蚜, 生命参数, 抗生性