بررسي اندام زايي گل در گونه گل كاغذي (Bougainvillea spectabilis Willd.)

The study of floral organogenesis in Bougainvillea spectabilis Willd.

Floral development in Bougainvillea spectabilis Willd., (Nyctanginaceae), together with the horticultural, pharmaceutical and agroforestry importance, is not yet well understood. The hermaphroditic and apetalous flowers of B. spectabilis have a 5-lobed tubular perianth, eight stamens with unequal filaments and one carpel. Epiphylly, phyllotaxis and placentation are all important morphological problems in the flowers of this species. To understand these problems better, a detailed study on floral organogeny in the species was first completed using epi illumination light microscopy. Our results revealed that organs of one flower develop regularly from the outer to the inner. Tepals, were the first organs which appeared helically in the margins of floral meristem. Soon after, eight stamens arised sequentially in a 3/8 spiral. Finally, the gynoecial wall was produced by the peripheral growth of the floral apex and then, the single ovule was formed from the gradual upgrowth and transformation of the floral apex. Our results showed that epiphylly was a result of cellular fusion between the base of the floral bud and subtended bract in B. spectabilis, which occured when floral development was completed