ULTRASTRUCTURAL-STUDY OF DIFFERENTIATION OF CONDUCTOR ELEMENTS IN TISSUE-CULTURE OF PASSIFLORA-QUADRANGULARIS L .1. CALLUS CULTURED IN DARK

Stem fragments of Passiflora quadranguaris were cultured in solid media at 28° C in the dark. We have obtained white and friable callus. The cytologic study reveales the existence of small meristematic centers which differenciate into parenchymatous cells and some tracheids.At the begining of the transformation of the meristematic cells into tracheids, the Golgi apparatus omits very small vesicles marked by the Thiery reaction; and, then, larger ones, which react negatively to this previous reaction. The endoplasmic reticulum increases considerably. The number of ribosomes and polyribosomes becomes very important at the beginning of the differenciation. At first, the mitochondries are very numerous, some of them remain, with dictyosomes and reticulum until the end of the cytoplasmic degeneration. © 1979, Japan Mendel Society, International Society of Cytology. All rights reserved.