Fine structure of kinetin-treated protonema and kinetin-induced gametophore buds in Funaria hygrometrica

F. Młodzianowski, A. Szweykowska


Besides occasional hypertrophy of grana and disintegration of stroma thylakoids occurring in some chloroplasts, no significant changes were found in ultrastructure of typical protonema cells treated for six days with kinetin. On the other hand, the fine structure of cells in kinetin--induced gametophore buds differed much from that of the protonema cells and showed characteristics of cells of with high metabolic activity and high division rates. The results indicate that cytokinins enhance development and differentiation in the protonema by activating only some of its cells, whereas the others remain unchanged or show symptoms of destruction and ageing. This is supported by the fact that in the presence of chloramphenicol, which prevents bud induction, kinetin acts synergistically with the inhibitor in producing degeneration and destruction of chloroplasts.

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