EFFECT OF GAMMA IRRADIATION, GIBBERELLIC ACID AND BOILING WATER ON SEED GERMINATION AND SEEDLINGS GROWTH OF Koelreuteria paniculata and Delonix regia

Abstract

Koelreuteria paniculata and Delonix regia is propagated by seeds. However, natural germination is delayed because of morphological dormancy and physiological dormancy in seed coat and seed embryo. In this paper, the different methods for breaking seed dormancy were investigated. The treatments included different doses of gamma irradiation (0.0, 100, 150 and 200 Gy), gibberellic acid (0.0, 50, 100, 200 and 400 ppm) and boiling water. Data were recorded on germination including; germination percentage, germination velocity, germination capacity, germination period and germination rate index. Furthermore, data on seedling growth after germination were recorded including plant height, number of main branches, shoot fresh and dry weights and root length. The chemical components (total carbohydrates, Chlorophyll-a, -b, total carotenoids, total soluble indoles and total soluble phenols) also were determined. The obtained results revealed that, there is a significant difference among the various methods used in breaking dormancy in seeds of Koelreuteria paniculata Laxm tree.