关键词: 天南星科, 传粉, 花序结构, 花信号, 花部挥发物

Abstract

Aims: Diverse inflorescence forms, pollination strategies, and widespread deceptive pollination make the Araceae family a suitable research subject for plant-pollinator interactions and the effects of floral divergence. Elucidation of flower diversity and pollination strategy in Araceae by the previous studies enhanced our understanding in floral divergence making a firm foundation for this study. The present review aims to summarize the main types of inflorescence structure, spathe forms, pollination strategies, and their relationship in the plants of the family Araceae.

Progresses: There are four main types of spathes in Araceae: unmodified spathe, expanded planar spathe, erect broad spathe, and erect narrow spathe; demonstrating an evolutionary trend from simple planar structures to complex three- dimensional wrapped spathe structures. There are three types of spadix with the evolutionary route from bisexual flowering inflorescence to monoecious inflorescence, and to diecious inflorescence. The Araceae exhibits five major pollination strategies: food-rewards mutualistic pollination, odor-attracting deceptive pollination, mating sites mutualistic pollination, oviposition-attracting mutualistic pollination, and lethal trap deceptive pollination. The main types of pollinators include: Diptera, Coleoptera, and Hymenoptera. Plants in the Araceae family attract pollinators by their unique shapes, colors, stripes, heat of the inflorescences, and most importantly floral scent. We comprehensively discussed the function of volatile organic compounds, among the most important volatiles being dimethyl sulfide, methyl indole compounds, terpenoids and benzene compounds that attract coleopteran beetles and Diptera to pollinate by simulating food or brood-site signals.

Prospects: Further study on the evolutionary ecology and developmental biology of Araceae is expected to provide reasonable explanation for maintenance and evolution of deceptive plant-pollinator relationships. Studies should increasingly focus on exploring the pattern of volatiles variation in species differentiation and the physiological relationship between volatiles and pollinators. Uncovering the complex relationships between floral diversity and pollination strategy in this family will greatly improve our understanding in its floral divergence and expand our knowledge in evolution of flower diversity in angiosperms.

Key words: Araceae, pollination, floral structure, floral signals, floral volatiles