Visualization Of Micromorphology Of Petal Epidermal Features Of Waxy And Velvety Flowers In Phalaenopsis

Phalaenopsis, also known as moth orchids, are well known for their use as potted plants and high-grade cut flowers. The flower petals of Phalaenopsis have two specific natural textures, waxy and velvety. In order to look for the factors that affect the flower petal textures, in this study, scanning electron microscopy (SEM) and optical microscopy were used to observed, compared, and analyzed the cell shape and arrangement of petal epidermal cells among seven samples from Orchidaceae family, including six Phalaenopsis cultivars of different colors and optical textures, and one Paphiopedilum sample as the out-group. The observational results revealed that waxy petals were formed by parallel and tight arrangement of flat epidermal cells with relatively thick and smooth cuticles, whereas soft (velvety) petals were formed by independent and loose arrangement of conical epidermal cells with thin cuticles. This research showed that the petal epidermal cell structure and arrangement and the accumulation of cuticles directly affect the petal texture of Phalaenopsis germplasm, but not strongly relate to germplasm sources, floral color, floral stripe color, and floral size. The study could provide basic information for further studies on floral texture formation mechanisms in Phalaenopsis, and could provide more insight and evidence for directional breeding of ornamental traits in orchid.