CORRELATIVE INHIBITION OF LATERAL BUD GROWTH IN PHASEOLUS-VULGARIS L ETHYLENE AND THE PHYSICAL RESTRICTION OF APICAL GROWTH

Restriction of apical growth in Phaseolus by enclosing the upper part of the shoot in sealed or ventilated tubes induced development of axillary buds beneath the enclosure. Enclosed parts of shoots showed a reduction of leaf growth and, in experiments where the tubes were sealed, of internode extension. Enclosure of the shoots in large vessels that did not restrict leaf expansion, but which contained 0·5 vols 10-6 ethylene, similarly induced axillary bud growth. Analysis of the gaseous extract of physically restricted shoots showed a 2·5-fold increase in ethylene concentration. The results suggest involvement of ethylene in the release of correlative inhibition brought about by physical restriction of apical growth. © 1979 Oxford University Press.