Influence of watering regime and mycorrhizae inoculations on the physiology and early growth of Acacia senegal (L.) Wild.

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