Ecophysiological Responses of Acacia raddiana savi and Acacia nilotica (L.) During Seedling Establishment in Extreme Arid Conditions

Abstract

The present investigation involves the studies on physiological responses of A. raddiana and A. nilotica seedlings under extreme arid conditions. Experiments were performed in a hyper arid environment to study the effects of drought stress using different water regimes at 12%, 9%, 6%, 4% and 2%. Photosynthesis and transpiration rate) were measured under full PAR range (0-2500μmols-1m-2) and instantaneous water use efficiency was calculated. A. raddiana and A. nilotica showed maximum Pn under 4% and 12% SMC respectively at high PAR levels, maximum E of A. raddiana recorded at 4% SMC and at 9% SMC in A. nilotica at highest PAR. The maximum WUE was noticed in A. raddiana at 12% SMC, while A. nilotica showed maximum WUE at 6% SMC at high PAR level. A. raddiana acted as water spender ideal desert plant at high PAR. Otherwise A. nilotica maximised Pn and minimised E giving maximum WUE at high PAR and low SMC levels.