Effect of some Growth Hormones on Seed Germination and Seedling Growth of some Savanna Tree Legumes

Studies were made on the effect of some growth hormones including Indole Acetic Acid (IAA) , Indole Butyric Acid (lBA) , Kinetin and Gibberellic Acid (GA₃) on seed germination and seedling growth of four savanna tree legumes. The tree species include Prosopis africana (Guil & Perr) Taub (Mimosoidae); Parkia biglobosa (Jacq) R. Br. Ex G. Don (Mimosoidae); Albizia lebbek (Linn.) Benth (Mimosoidae) and Senna siamea (Lam) Irwin Barneby (Caesalpinoidae). 0.01-0.04ppm IAA enhanced germination in A. lebbek , P. biglobosa , P. africana and S. siamea. 0.01-0.05ppm IBA enhanced germination in P. africana and S. siamea. 0.01-0.05ppm kinetin retarded germination in P. biglobosa , P. africana and S. siamea. 0.01-0.05ppm. GA₃ enhanced germination in A. lebbek and P. africana. 0.01-0.05 ppm IAA enhanced plant height and dry weight in the seedlings of the four tree species. 0.01-0.03 ppm IBA enhanced plant height and dry weight in S. siamea and only plant height only in P. biglobosa. IBA (0.03-0.04 ppm) enhanced leaf number in P. biglobosa and A. lebbek. Kinetin (0.01-0.05 ppm) enhanced leaf number in P. biglobosa. GA₃. enhanced leaf number and plant height in P. biglobosa and plant height in A. lebbek.