The effect of phytochrome and white light of high and low intensity on the uptake and distribution of ¹⁴C‐labelled kinetin in radish seedlings (Raphanus sativus)

Abstract

The influence of light intensity and phytochrome on the uptake of 14C‐kinetin (6‐furfurylamino‐[8‐ 14C]‐purine) by the plant and the translocation of the phytochrome between the roots, the hypocotyl and the cotyledons were investigated with radish seedlings (Raphanus sativus L. cv. Saxa Treib) grown in the dark or under white light of high (20,000 lux, 90 W m−2) or low intensity (2,000 lux, 14 W m−2). The highest uptake of labelled kinetin was found in plants grown in continuous darkness. The total uptake of kinetin was decreased by strong light and to a finally higher extent by weak light. Under white light most of the kinetin accumulated in the root, whereas in the dark an enhanced translocation of the phytohormone into the cotyledons was observed. In etiolated radish seedlings, light acting on phytochrome (daily 5 min red or far red light pulses) decreased the translocation of 14C‐kinetin into the cotyledons. Under far red light a pronounced uptake of the phytohormone into the roots was found. The data are discussed with regard to the interaction of light and phytohormones on plant development.

Effect of benzyladenine on development of derooted watermelon seedlings

“…Cytokinins can be applied to such "half-seedlings" either as a droplet of solution between the cotyledons or by dipping the hypocotyl stump in the hormone solution. The effects of the two treatments are likely to be different since cytokinin transport can be polarized either in acropetal or in basipetal direction (Radin and Loomis 1974, Ramina et al, 1979, Buschmann and Grumbach 1981, Hutton and van Staden 1982a.…”