engleski

Greening of non-transformed and Agrobacterium rhizogenes transformed adventitious potato roots

Light-induced chloroplast differentiation in potato (Solanum tuberosum L. cv. Istra) was studied in cultures of adventititious roots originally induced in vitro on nodal plant segments, and of hairy roots transformed with Agrobacterium rhizogenes, mannopine-type, strain 8196. Red fluorescence, due to chlorophyll accumulation, was first observed, in hairy roots, after 2 - 3 days of light exposure and several days later in cultured normal roots. In both cases, the concentrations of chlorophyll and carotenoids then increased gradually. As evidenced by electron micrographs, the chloroplasts developed from leucoplasts via a sequence of leuco-chloroplasts. DAB (diaminobenzidine) positive thylakoids first appeared in leuco-chloroplasts indicating the beginning of photosynthetic activity. The photosynthetic activity of green hairy roots was higher than that of green non-transformed roots. In non-transformed potato roots, BA stimulated while IAA and GA3 inhibited light-induced pigment accumulation.

agrobacterium rhizogenes; chloroplast differentiation; chlorophyll; leucoplast; photosynthetic activity; Solanum tuberosum; transformed and non-transformed roots

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