Microbiology Research Journal International

Aim: Determine the effect of different inoculum concentrations of T. harzianum from semi - arid soils on the activity of antioxidant enzymes of maize seedlings under water stress.

Methods and Results: This study employed a three-factor factorial (3×4×4) design, arranged in a completely randomized design (CRD) with three replications. Three maize varieties (H614, H629 and H6210) were treated with four concentrations of T. harzianum (0, 1x10⁵, 1x10⁷and 1x10¹⁰ spore/ml and thereafter grown under four osmotic potential regimes (0, -0.3, -0.6 and -0.9 MPa). Results from the study showed that T. harzianum had a significant effect on Superoxide dismutase (SOD) and catalase (CAT) activity of maize seedlings and did not enhance either maize seed germination or seedling growth. The activity of SOD and CAT was significantly enhanced by T. harzianum in all the three varieties of maize. Optimum SOD and CAT activity were recorded in seeds treated with 107 spores/ml of T. harzianum. Under normal growth conditions (0MPa), SOD and CAT activities were not enhanced by T. harzianum. However, under severe water stress (-0.9MPa), maximum activity of the enzymes was registered in all the three varieties of maize.

Conclusion: Maize seedling colonization by T. harzianum enhanced systems of antioxidative enzymes. Maximum activity of these enzymes was recorded under severe water stress (0.9MPa) mainly in seedlings treated with 10⁷ spores/ml of T. harzianum. Consequently T. harzianum from semi-arid soils may be employed to improve maize plants’ tolerance to water stress.

Significance and Impact: With rapid increase in human population, coupled with global climate change, there is need to devise a cheap and safe option to increase the production of food crops. The ability of T. harzianum in promoting plant growth precisely maize under stress is of importance.