Effect of in vivo and in vitro application of the cytokinin N-6-(m-hydroxybenzyl)adenosine on respiration and membrane transport processes in sugar beet

Sugar beet grown in pots was sprayed with N-6-(m-hydroxybenzyl)adenosine, (mOH)[9R]BAP, one of the synthetic cytokinins. Root tissue was then examined for respiration and for H+-adenosinetriphosphatase activity and both leaf and root tissue served as the object for 6-deoxy-D-glucose and 2-aminoisobutyric acid uptake estimations. Treatment with (mOH)[9R]BAP depressed the uptake of oxygen by the roots of both young and old plants by 17 - 30 % while addition of (mOH)[9R]BAP to the respiring slices decreased it by 10 - 23 %. Uptake of 6-deoxy-D-glucose was mostly diminished by in vivo spraying with the cytokinin (by up to 12 % in leaves and by up to 60 % in roots), as well as by adding it to the experimental vessel (insignificantly in the leaves but by up to 80 % in the roots). The H+-ATPase activity was stimulated both in vivo and in vitro appreciably in young plants but not at all in plants at the end of their vegetation period.