Abstract:
Ontogeny and the developmental pattern of flower organs of Brassica napus (cv. Hyola) were investigated using epi-illumination microscopy and image analyzing. Similar results as compared with Scanning Electron Microscopy (SEM) were obtained with this simplified and amenable procedure. Using this microscopy technique we have demonstrated that after the transition of the vegetative apex into the reproductive apex in the 3-leaved seedlings, flower primordia initiation takes place in a helical phyllotactic pattern and the initiation of flower organs pursues the following steps; sepals, stamens, gynoecium and petals. In the formation of four sepals, the abaxial sepal primordium initiated first and it was followed by the formation of the two others in the lateral position. The adaxial sepal primordium was initiated in the last step. Of the six stamens, the four long ones, were initiated first and they were positioned in an alternating order with the four sepals. The two short stamens were initiated in a basipetal manner and in the outside of the long stamens, opposite to the lateral sepals. The remainder part of the apex grows upward to produce an oval, hollow tube which will form the gynoecium. Petal primordia grow slowly and they were initiated after stamens and gynoecium initiation on either side of the two short stamens. The gynoecium at maturity was characterized with a papillated stigma and an elongated style. The ovary was long and divided by a septum in the internal side of the ovary. Sepals, style and the abaxial zone of anthers showed stomatas but they were absent in the petals.
F. Valipour, M. Khosrowchahli, J. Karapetian and M.R. Dadpour, 2007. A Developmental Study of the Inflorescence and the Flower of Rapeseed (Brassica napus. cv. Hyola) Using Epi-Illumination Light Microscopy. Journal of Biological Sciences, 7: 1139-1146.
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