STUDIES ON SEED GERMINATION OF SAUSAGE TREE (KIGELIA PINNATA (JACQ) D.C.)

Abstract

The present study was conducted under the full sun at the nursery of Orman Botanic Garden, Hort. Res. Inst., Giza, Egypt during 2014 and 2015 seasons in order to reveal the response of Sausage tree (Kigelia pinnata (Jacq) D.C.) seeds to some pregermination treatments including, seeds without treatment (control), soaking in tap water for either 24 or 48 hours under room temperature, soaking in hot water (60-70 °C) for 24 h. and soaking in diluted sulphuric acid (50 %) for either 1 or 2 h. which followed by soaking in tap water for only 12 h. under room temperature in a complete randomized experiment, with 3 replicates of 10 seeds. The results of the study have shown that the maximal percent of germination was achieved in the two seasons by soaking the seeds in tap water for 48 h treatment which followed by soaking also in tap water, but only for 24 h, while the least germination % was attained in both seasons by soaking either in hot water (24 h) or in diluted H2SO4 (1 or 2 h.). The tap water soaking for 48 h treatment was also accelerated germination rate and velocity more than the control, but hot water and diluted H2SO4 treatments significantly delayed them. Most of the used treatments slightly improved the mean of germination rate index with non-significant differences in between, whereas the means of vigour index, seed viability, hypocotyl length of the germinated seeds, seedling and root lengths, No. leaves/seedling, fresh and dry weights of leaves and roots, as well as leaves content of chlorophyll a, b, carotenoids and total soluble sugars were only improved by soaking in tap water for 48 h treatment that recorded the highest averages compared to control in most cases of both seasons. The leaf content of total indoles was fluctuated in both seasons, while that of total phenols was markedly decreased only in the seedlings generated from the seeds soaked in tap water, especially for 48 h., as this treatment generally gave the best equilibrium between total indoles and total phenols content in the two seasons. Hence, it can be advised to soaking the seeds of Sausage tree in tap water for 48 h. before sowing under the ambient conditions to get the best germination traits and highest quality of the seedlings.