Morphogenetic Effects of Roots and of Some Synthetic Cytokinins inVitis viniferaL.

Abstract

In woody cuttings of the grape vine, inflorescences of fertile buds usually fail to develop and atrophy soon after bud burst. Results presented here indicate that this effect is related to absence of roots at planting. Inflorescences were retained in pre-rooted cuttings which were propagated by holding the temperature of the medium at 25° C and the air temperature at 4° C. Similar effects on inflorescence growth were obtained by applying synthetic cytokinins to the bases of unrooted cuttings in solution cultures, and by applications to emergent inflorescences. Promotion of inflorescence growth was found with 6-benzyl-aminopurine (BAP) and 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H purine (‘SD 8₃₃₉’). Stimulation of inflorescence growth by BAP was accompanied by reduction in vegetative growth, and by development of red pigments in inflorescences and leaves. Results of cincturing experiments indicate that BAP is transported acropetally in the xylem of vines. Effects of roots, and effects of synthetic cytokinins, are discussed in relation to recent discoveries of endogenous cytokinins in the ascending sap of vines.