Physiological Responses of Maize to Arbuscular Mycorrhizal Fungi Under Variable Phosphorus and Nitrogen Levels.

Arbuscular mycorrhizal fungi (AMF) colonize plant roots and the surrounding soil to symbiotically provide water and nutrients to the host plant in exchange for carbon fixed by the plant. The AMF symbiosis is part of a complex interaction among the plant, the fungus, and the environment. Plant and fungal genotypes, and the soil environment all contribute to the outcome of the symbiosis. The objectives of this study were to study the physiological impact of AMF on maize hybrids grown under different soil N and P levels. A greenhouse experiment was conducted to study the effect of two P (31 and 61 ppm) and three N (0, 105 and 210 ppm) rates on the response of AMF-inoculated and non-inoculated maize hybrids. AMF inoculum was a mixture of four species (Glomus deserticola, Glomus intraradices, Glomus mosseae and Gigaspora gigantean). Maize hybrids included two drought tolerant hybrids and two drought sensitive hybrids. The experiment was arranged in a randomized complete block design with 4 replications. The number of leaves, plant height and chlorophyll content were recorded weekly up to the 10^th week after planting (WAP). Fresh and dried biomass of shoots was recorded at 10 WAP. N and P contents in dried shoot biomass were measured. Percent root colonization by AMF was measured, and one AMF biomarker (C16:1cis11) was measured in root and soil. The results of this study will provide a better understanding of how different maize genotypes respond to AMF inoculation and their interaction with different levels of nitrogen and phosphorus fertilization. Improved understanding of this important symbiosis under a scenario of climate change could potentially lead to more sustainable farming practices and increased primary food production.