Phosphorus Uptake In Sorghum Seedlings Colonized With Arbuscular Mycorrhizal Fungi

ABSTRACT

The process of re-establishing the natural level of arbuscular mycorrhizae (AM) fungi richness can represent a valid alternative to conventional phosphate based fertilization practices, with a view to sustainable agriculture. The main strategy that can be adopted to achieve this goal is the direct re-introduction of AM fungi inoculum into a target soil. AM fungi have a high affinity for phosphorus, an essential macronutrient that participates in the skeleton of the nucleic acids DNA and RNA. The aim of the study was to determine the effect of AM fungi on sorghum growth by measuring phosphorus uptake by the plant and the plant height. The AM fungi propagules were collected from the starter soil in Matopos. The propagules were identified by clearing the roots in 10% KOH and then staining in Methylene blue prior to microscopic analysis. After positive identification propagules were multiplied in greenhouse pot plants using the bait plant sorghum for 6 weeks. The inoculum was then transferred to the pot trials, using three different soil types red, black and sandy. After 6 weeks the sorghum seedlings were measured for phosphorus and plant height. The soil types were measured for phosphorus before and after the trials. AM fungi significantly increased plant phosphorus (p=0.0) and significantly increased plant height (p=0.013). There was no interaction between AM fungi and soil type in influencing plant phosphorus as there was no significant difference (p=0.073) and no interaction in influencing plant height as there was no significant difference (p=0.534). AM fungi inoculum has significant potential to be used as a natural bio-fertilizer. However, more field experiments need to be done to see the performance of AM fungi in an uncontrolled environment.