Hu, Guang-Wan , Lei, Li-gong , Liu, Ke-Ming , Motley, Timothy .
Floral development in Euryale ferox (Nymphaeaceae).
Euryale ferox is an annual water lily distributed in Eastern Asia. It usually occurs in lakes and ponds. The giant prickly floating leaves, which are 1.3- 2.7 m in diameter and similar to the Victoria water lily are very attractive. Flowers are epigynous, floating or often partially or entirely submerged, sometimes cleistogamous. The flowers have four persistent sepals, numerous petals, that transition gradually to numerous stamens. The carpels (5-16) are completely united and the stigma is sessile and radiate on cup-shaped stigmatic disc. The fruit irregularly dehiscent and seeds are arillate, rigid, with abundant starchy perisperm. In China, the seeds of E. feroxare traditional medicine and starchy resource. In order to provide evidence regarding the phylogenetic position of Euryale and to reveal evolutionary trends of floral ontogeny in Nymphaeaceae SEM studies of Euryale were compared to other genera. Our results showed that each floral primordium initiated was associated with a leaf primordium at the rhizome apex. Every flower is ebracteate and in a non-median axillary position to the associated leaf. Also the sepal primordia are initiated unidirectionally with the abaxial one initiated first, followed by two laterals and the adaxial sepal. Petal and stamen primordia are numerous, initiated simultaneously in whorls. Plicate carpels are initiated in a single whorl simultaneously at the lowermost part of a depression. In the center of the depression, a dome-shaped structure is formed and soon enlarges upward and becomes a conical projection at the center of the stigmatic cup. This is regarded as a floral apical residuum. In conclusion, the floral organogenesis of Euryale is most similar to Victoria.It also shares similarities with Nymphaea,except that the floral apex of Nymphaea becomes depressed at a later stage and only carpels are initiated in the depression. Therefore, Euryale should be treated in the Nymphaeaceae together with Victoria and Nymphaea.
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1 - Kunming Institute of Botany, Chinese Academy of Sciences, Key Laboratory of Economic Botany and Biotechnology, Kunming , Kunming, 650201, China
2 - Hunan Normal University, Department of Botany, Changsha, Changsha, 410081, China
3 - Old Dominion University, Biological Sciences, 110 Mills Godwin/ W 45th St., Norfolk, VA, 23529, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Delaware B/Hyatt
Date: Wednesday, July 11th, 2012
Time: 4:45 PM