EFFECTS OF SEED CHILLING OR GA(3) SUPPLY ON DORMANCY BREAKING AND PLANTLET GROWTH IN CERCIS-SILIQUASTRUM L

Germination and post-germination events have been compared in seeds of Cercis siliquastrum whose dormancy was removed by fulfilling the natu ral chilling requirement or by exogenous GA(3) application. Compared t o the chilled ones, the GA(3) treated seeds showed precocious embryo g rowth and an earlier reserve mobilization, which started before radicl e emergence. Although the hormonal application was interrupted at seed germination, the plantlets of Cercis siliquastrum that originated fro m GA(3)-supplied seeds were taller than those from chilled ones. Moreo ver, they produced a greater number of leaves but a reduced root mass and had some difficulty in maintaining a good water balance. Thus, the treatment of Cercis siliquastrum seeds with exogenous GA(3) broke dor mancy and induced germination, but also caused long-lasting consequenc es on morphogenesis of the growing plantlet.