FLOWERING INFLUENCES ADVENTITIOUS ROOT-FORMATION IN CHRYSANTHEMUM CUTTINGS

Root formation in chrysanthemum (Dendranthemum grandiflora (Ramat.) Ki tamura) cuttings was reduced as flowers developed on stock plants. Thi s effect was shown for all ten cultivars evaluated in this study. Not all cultivars were affected equally by the presence of flower buds on cuttings. There was no relationship (r(2) = 0.06) between root formati on in Vegetative cuttings and the ability for a cultivar to root from flowering cuttings. IBA (1 mM) could partially overcome the negative e ffect of flowering on root formation, but cuttings taken after the flo wer buds had fully opened failed to root even after auxin treatment. R emoving buds from cuttings or continually removing flower buds during stock plant growth reduced rooting compared to cuttings with flower bu ds intact. Furthermore, cuttings taken from the top three nodes of the stock plant containing flower buds rooted comparably to cuttings take n from the lower stem section that contained only vegetative buds. The negative influence of flowering on root formation appears to be due t o the photoperiodic induction of the flowering stimulus rather than a direct competition for resources between flowers and developing roots. (C) 1997 Elsevier Science B.V.