PDF(Pubmed)
Abstract：
Opisthopappus is a perennial, endemic herb of the Taihang Mountains in China. Two species of this genus (O. longilobus and O. taihangensis) are important wild genetic resources for Asteraceae; however, their reproductive biology has been lacking until now. This study is the first detailed report on the reproductive biology and breeding systems of two Opisthopappus species. Through field observations, the floral syndromes of O. longilobus and O. taihangensis were found to possess a similar pattern, although O. taihangensis has a relatively larger capitulum, more ray ligules, and disc florets. The flowers of both O. longilobus and O. taihangensis are protandrous, a character that can prevent autogamy at the single-flower level, and insects are required for pollination. Further, brightly ligules, brightly bisexual florets, unique fragrance, and amount of nectar suggest that these species propagate via an entomophilous pollination system. Hymenopteran and Diptera species were observed as the effective pollinators for these two species. The outcrossing index, pollen/ovule ratio and the results of hand pollination indicated that these Opisthopappus species might have a mixed mating system that combines cross-fertilization and partial self-fertilization for O. longilobus and O. taihangensis, outcrossing predominated in the breeding system, while self-pollination played an important role in seed production when insect pollination was unavailable, particularly in a harsh environment, such as the Taihang Mountains cliffs. Meanwhile, O. taihangensis might better adapt to severe surroundings with relatively complex floral syndromes, specifically through the attraction of visiting insects and a high seed set rate. The above results not only provide reference information toward a better understanding of the survival strategies of O. longilobus and O. taihangensis in the Taihang Mountains but also lay a solid foundation for further exploring the molecular mechanisms that underly their adaptation under cliff environments.
摘要：
Opistopappus是多年生的，中国太行山特有草本植物.该属的两种（O。longilobus和O.taihangensis）是菊科的重要野生遗传资源；但是，到目前为止，他们的生殖生物学一直缺乏。这项研究是有关两种Opistopappus物种的生殖生物学和育种系统的第一份详细报告。通过实地观察,发现O.longilobus和O.taihangensis的花卉综合征具有相似的模式，虽然太汉根有一个相对较大的头颅，更多的射线舌状组织,和圆盘小花。O.longilobus和O.taihangensis的花都是有质子的，一个可以在单花水平上防止自交的角色，和昆虫需要授粉。Further,明亮的舌状，明亮的双性恋小花，独特的香味，花蜜的数量表明这些物种通过昆虫授粉系统传播。观察到膜翅目和双翅目是这两个物种的有效传粉者。超越指数，花粉/胚珠比例和人工授粉结果表明，这些Opistopappus物种可能具有混合交配系统，该系统结合了O.longilobus和O.taihangensis的交叉受精和部分自体受精，异交在育种系统中占主导地位，当昆虫无法授粉时，自花授粉在种子生产中起着重要作用，特别是在恶劣的环境中，如太行山悬崖。同时,太汉可能更好地适应具有相对复杂的花卉综合征的严重环境，特别是通过吸引来访的昆虫和高种子率。以上结果不仅为更好地了解太行山Ol.longilobus和O.taihangensis的生存策略提供了参考信息，而且为进一步探索其在悬崖环境下适应的分子机制奠定了坚实的基础。
