Regulation of Flowering in Orchids

Abstract

Orchids constitute the largest families within the flowering plants; they are one of the most highly evolved groups in the angiosperms; and because of their flashy flowers many species from several genera are very prominent horticultural commodities. Environmental factors such as temperature and daylength influence flowering; however, other factors play a major role such as the developmental stage, plant hormonal regulation and genetic factors. Research on model plants such as the thale cress (Arabidopsis thaliana) and rice (Oryza sativa) has allowed a broad understanding of the genetics and the molecular regulation of flowering in most plants. However, until very recently the specifics of floral regulation in orchids had remained quite obscure. In this review we have examined very recent work concerning flowering of orchids with a focus on the interplay between development, environmental cues, plant hormones, and gene networks. We have highlighted several examples of successful manipulation of flowering through biotechnology that may be very relevant for researchers and growers elsewhere.