Certain aspects of xylem differentiation in corn

摘要: Differentiation of vessel elements in corn is accompanied by marked changes nearly all organelles except plastids. The young cells increase volume and apparently synthesize new cytoplasmic protein. initiation wall thickening an aggregation microtubules specific locations the number mitochondria dictyosomes. During period active deposition, endoplasmic reticulum (ER) shows a highly elaborate form, harbors intralamellar tubules, blankets those parts which remain unthickened. Dictyosomes seem to produce at least two types vesicles, one may serve as carrier lignin precursors. final autolysis involves progressive removal vacuolar membranes, plastids, dictyosomes, vesicles associated with secretion noncellulosic polysaccharides, microtubules, finally plasmalemma, cell wall, cytoplasm. Mitochondria ribosomes are degenerated. ER probably plays important rol...