作 者 ：李鹂,党承林
期 刊 ：生态学报 2007年 27卷 2期 页码：571~578
关键词：短葶飞蓬；开花特征；杂交指数；花粉-胚珠比；繁育系统；
Keywords:Erigeron breviscapus (Vaniot.) Hand.-Mazz., flowering characteristics, out-crossing index, pollen-ovule ratio, breeding system,
摘 要 ：通过野外观察，运用杂交指数、花粉-胚珠比、套袋实验等方法，对短葶飞蓬自然种群的开花状态及繁育系统进行研究。结果如下：短葶飞蓬具头状花序，由外围舌状花及中央的管状花构成。种群花期一般为4~7月份，一个花序的花期约为19~25d。管状花单花花期一般为7~10d，聚药雄蕊，先熟，药室内向开裂，成熟的花粉散于花药筒中。花开后花柱快速伸长，导致雄蕊伸出花冠，同时将药筒中的花粉粒“推”出药筒，形成花冠、药筒、柱头三者在空间上的分离。花序中不断有小花开放，同一花序内的小花间具相互传粉的机会。杂交指数≥4，判断繁育类型属于异交，部分自亲和，需要传粉者。P/O值约为1373，判断繁育类型属于兼性异交。套袋实验证明短葶飞蓬异花授粉，虫媒，蜂、蝶为主要传粉者。在自然状况下，短葶飞蓬结实率较低的原因可能是花粉竞争。此外，短葶飞蓬存在天然雄性不育植株，为遗传育种提供了材料。
Abstract:Erigeron breviscapus (Vaniot.) Hand.-Mazz., is a perennial herb in the Asteraceae family. It is an important plant used for medicine by the Miao people, as an elixir. A field investigation was conducted on the floral syndrome and breeding system of in Kunming, Yunnan Province. The main results are as follows: the capitulum of E. breviscapus is an inflorescence with centripetal development, the outer ligulate florets develop first, followed by the inner florets. The flowering period of the E. breviscapus population lasted about three months. The life span of one inflorescence was usually about 19-25 days. The life span of one floret was approximately 7-10 days. All florets being protandrous, the mature pollen dispersed in the anther canister. On the day of anthesis, the pistil recipient phase started from style elongation and the stigma was bilobed. It follows that the stamen are exserted from the corolla, and the pollen is "pushed" out the anther canister by the stigma. As a result, there is a spatial isolation of corolla, anther canister and stigma within the same floret. In an inflorescence, outer florets are in the female phase (pistil recipient) when anthesis of inner florets takes place. Thus, outer florets have the chance of being pollinated by the inner florets in the same inflorescence. The out-crossing index (OCI) is ≥ 4. According to criteria put forward by Dafni, the reproduction of E. breviscapus can be determined as out-crossing, partially self-compatible, and requiring pollinators during pollination. The pollen-ovule ratio (P/O) is approximately 1373. E. breviscapus reproduction is facultative xenogamy by Cruden’s criterion. When the inflorescences were bagged, there were few fruits produced. Thus, it is concluded that out-crossing is predominant in the breeding system of this species and fruit setting is depended on visiting pollinators. More than 10 species of floral visiting insects were observed on inflorescences of E. breviscapus. The most common floral visitors were species of bees and butterflies. Pollen competition may be the major factor leading to low fruit setting by E. breviscapus in nature. In addition, the male sterile plants were found in a natural condition and are valuable for breeding.