IMPROVED GERMINATION OF THE SEEDS OF WHISTLING PINE (CASUARINA-EQUISETIFOLIA) FORST AND FORST (CASUARINACEAE) BY VARIOUS PRESOWING TREATMENTS

Various methods were tried for inducing the seeds of Casuarina equisetifolia Forst and Forst (Casuarinaceae) to germinate faster or in greater numbers than under natural conditions. Percentage germination in untreated seeds (control) ranged from 7 to 16% over an average of 6 days. Some treatments increased the percentage germination by different values up to 62%. The most effective treatment was application of a 0.1 mM solution of GA3 followed by that of a 2 500 mg dm-3 solution of ascorbic acid, and a 10 mM solution of NaNO3. Other effective treatments included scarification with concentrated H2SO4, and application of 0.1 mM IAA solution. Incubating soaked seeds in continuous red light caused the germination to start earlier and also increased the overall germination. Germination was inhibited under continuous blue light, green light and in the dark. Germination was completely prevented in seeds pretreated with a 0.1 mM solution of ABA.