Abstract

Acacia senegal is endowed with features that give it potentials for ecosystem stabilization, anti-desertification and for production of high quality gum-Arabic. However, the natural population which is becoming low has been traced to poor seed germination and seedling survival. The influence of watering regime and mycorrhiza inoculation on some physiological parameters and early growth of A. senegal in the semi arid region of Nigeria was investigated. Inoculated seedlings had higher stem growth, chlorophyll content and leaf number than those without inoculation. Also, seedlings that were watered twice per week had higher stem growth and leaf number than those that were watered daily and once per week. The stomata conductance of Acacia seedlings was best for seedling batch that were watered twice weekly without mycorrhiza inoculation and also when inoculated with ectomycorrhiza. However with endomycorrhiza, the seedling batch that received weekly watering had the highest conductance while it was least in the seedling batch that received daily watering. The same trend was observed for the xylem pressure potential. At 16 weeks after planting, seedlings that were watered once weekly wilted irrespective of whether they were inoculated or not. Mycorrhizae inoculation of A. senegal seedlings combined with twice weekly watering in the semi arid region of Nigeria will be appropriate for healthy and good seedling performance in the nursery.

Key words: Ecto- and -endo mycorrhiza, Xylem pressure potential, chlorophyll,stomata conductance.