Effects of sed chilling or GA3 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 natural chilling requirement or by exogenous GA3 application. Compared to the chilled ones, the GA3 treated seeds showed precocious embryo growth and an earlier reserve mobilization, which started before radicle emergence. Although the hormonal application was interrupted at seed germination, the plantlets of Cercis siliquastrum that originated from GA3-supplied seeds were taller than those from chilled ones. Moreover, 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 exogenousGA3 broke dormancy and induced germination, but also caused long-lasting consequences on morphogenesis of the growing plantlet.