Effects of dry heat on seed germination in selected indigenous and alien legume species in South Africa

The effect of dry heat on the percentage germination, germination rate and lethal temperatures of selected legume species was investigated by exposing seeds to different intensities and durations of heat. Two alien invasive legumes (Acacia saligna and A. cyclops) and two indigenous legume species: Podalyria calyptrata, which is a fynbos species, and Virgilia oroboides, a forest precursor, were tested. Results were compared to predictions based on published accounts of the species’ ecology. Acacia saligna and P. calyptrata fitted predictions: high percentage germination, fast germination rates and a tolerance to high temperatures; with A. saligna outperforming P. calyptrata in the latter two responses. Both A. cyclops and V. oroboides did not conform to predictions: dry heat had little positive effect on germination, and in A. cyclops it had a negative effect