Effectiveness of Endomycorrhizal Fungi and Pseudomonas fl uorescens Under Different Phosphorus Levels on Capsicum annuum L.

Abstract

The contribution of two indigenous arbuscular mycorrhizal fungi—Glomus mosseae (G) and Acaulospora laevis (A)—along with Pseudomonas fl uorescens (P) was examined at three levels of superphosphate fertilization (F1, 0.200 g per pot; F2, 0.500 g per pot; and F3, 0.800 g per pot) for Capsicum annuum L. plants in a pot culture experiment in sterilized soil. After 120 d of inoculation, plants were harvested and analyzed for arbuscular mycorrhizal (AM) spore number, AM root colonization, alkaline phosphatase, acid phosphate, and root and shoot phosphorus. The lowest dose of phosphorus fertilization best promoted the growth of mycorrhizal fungi in terms of increasing the AM colonization and spore number compared with the two higher doses, as F1 had the maximum root colonization of 97.62%, which decreased to 76.2% and 23.4% with applications of F2 and F3, respectively. Of the two AM fungi, G. mosseae was found to be the better strain when applied along with P. fl uorescens. Increasing the phosphorus fertility decreased all the above measured parameters. The results showed that the activity of both acid and alkaline phosphatases increased with root colonization and was highest in the treatment with triple inoculation. There was a signifi cant increase in the phosphorus content in F1 plants due to enhanced mycorrhization of roots which increases the secretion of phosphatases that helps increase phosphorus uptake in the plant and ultimately increases the fruit yield. On the basis of the results found in this study, G+P and G+A+P treatments in F1-fertilized plants were found to produce the largest increases of AM root colonization, phosphatase activity and phosphorus content and thereby increasing the yield of bell pepper plants.