Abstract: Prethrum cinerariifolium Trev. is the raw industrial material for extracting natural pyethrins,which exists in all parts of Pyrethrum plant,especially in ovaries in capitulum. The oil glands of vessels on ovary walls change from the formation and development to the transformation of secretion in the process of flower bud development ,flowering had seed maturation. The contents of pyrethrins markedly vary in different growing stages. It is divided into eight stages from the flower bud stage to maturation time of seeds,in order to understand the relationship between florets development stage and contents of pyrethrins in capitulum of Pyrethrum cinerariifolium.

Key words: Pyrethrum cinerariifolium, Flowering chracteristics, Pyrethrins, Oil gland, Dry matter, Suitable harvest time

摘要： 除虫菊(Pyrethrum cinerariifolium)是提取天然除虫菊酯的原料，植物体的各个部位均有除虫菊酯分布，最主要存在于头状花序(简称花头)的子房中，随着花蕾的孕育、开花直至种子(瘦果)成熟，子房壁导管的油腺也同时经历了发生、发展和分泌物转化的过程。直接反映在开花期的不同阶段所采摘的花头内菊酯含量的变化十分显著，为了进一步认识除虫菊开花期小花开放程度与菊酯含量变化的内在规律，把除虫菊开花期(从孕蕾盛期到瘦果成熟)划分成8个阶段。通过样品测定，了解开花期花头中菊酯含量的变化状况和头状花序发育过程中小花子房的增长与干物质积累之间的关系，表明头状花序的小花开放至第4至第5阶段，即花头上管状小花开放初盛期至盛期时采摘，是获得最高生物产量和菊酯含量的最适宜采摘期。

关键词: 除虫菊, 开花特性, 除虫菊酯, 油腺, 干物质, 适宜采摘期