Presowing treatments of Acacia Senegal seed: germination and growth
Keywords:Acacia senegal, Presowing treatments, Germination, Water uptake, Seed treatments
AbstractPresowing treatments including scarification, osmotic priming and hardening were applied to seeds of Acacia senegal (L.) Willd. from Goz Ashgar, Sudan. Seeds exhibited a typical triphasic pattern of water uptake leading to germination. Germination occurred continuously over a maximum of 18 days depending on presowing treatment and temperature. Chemical (HCl for 60 min) and mechanical (3 min with a hand scarifier) scarification improved germination rate without changing germination capacity. Chemical scarification with H2SO reduced both germination rate and capacity. Osmotic priming with K3PO4 (-0.05 MPa), CaCl2 (-0.06 MPa) and PEG6000 (-0.1 MPa) increased the germination rate of treated seeds. Hardening of seed with distilled water had no significant effect on germination rate or capacity. Germination capacity was high for temperatures between 20 and 40°C (85 to 93±3% respectively) but fungal attack increased with increasing temperature. Emergence time for seedlings in glasshouse trials was decreased by presowing treatments. Height growth rates were reduced by all treatments. Though watering regimes affected the final biomass production, presowing treatments did not affect root or shoot biomass.