بررسي مراحل تكويني سلول‌هاي پاپي كلاله تاتوره (Datura stramonium L.)

Ontogenetic and structural study of the stigmatic papillae in Datura stramonium

Datura stramonium L., of the family Solanaceae, is a toxic and medical annual. Its flowers are white with a pentamerous trumpet shaped corolla, five stamen and two fused carpels. The stigma is of the wet and papillate type. In the present study, the ontogenetic aspects of papillae were investigated using light and floresance microscopy. The papillae were unicellular and originated from the epidermis at the apex of very young style (within buds <10 mm in length). In the course of development, they progressively covered the stigma, then lysed and detached from its surface. This was an early - began in >15 mm long buds - and continuous process and caused almost lack of the papillae in pollinated opened flowers. Papillae as well as underlying stigmatic cells showed secretory activity during their development. Secretion began very early in 20-25 mm long buds, after post-fixation Auramine O revealed their lipoid nature. With further development a large number of lipoid droplets were observed just below the cuticle. In the mature stigma (in 40-60 mm long buds) droplets increased in number, coalesced and formed large lipid bodies under the cuticle and on the stigma surface. This procedure caused the cuticle to rupture and become distanced from the cell wall. It seemed that lipoid exudates passed through the ruptures and reached the stigma surface. Otherwise, the existence of these ruptures may facilitate the passage of the lipoid material that occurs through the thin cuticle.