Impact of Arbuscular Mycorrhizal Fungi On Maize Physiology and Biochemical Response Under Variable Nitrogen Levels.

Arbuscular mycorrhizal (AM) fungi are known for colonizing plant roots, transporting water and nutrients from the soil to the plant. Therefore, environmental conditions set mainly by soil water and nutrient levels are important determinants of AM function and host plant response. Mechanisms of nitrogen (N) uptake, translocation and transfer to the host plant by AM fungi are only partially understood for a few select host plants. This is due mainly to the AM/plant symbiosis being dependent on experimental conditions and host species, in addition to complex interactions between N and other nutrients. The objectives of this study were to study the physiological impact of AM fungi on maize grown under different N levels. A greenhouse experiment was conducted to study the effect of four N doses (0, 1.5, 7.5 and 15 mM NO₃^-) on the response of AM-inoculated and non-inoculated maize plants. AM inoculum was a mixture of four AM fungal species (Glomus deserticola, Glomus intraradices, Glomus mosseae and Gigaspora gigantean). The experiment was arranged in a randomized complete design with 4 repetitions. The number of leaves, plant height and chlorophyll content were recorded weekly between the third and seventh week after planting (WAP). Fresh biomass of shoots and roots were recorded at 7 WAP. N and P contents in fresh and dry shoot biomass were measured. Results from this study will provide much needed information for future experiments on drought response of conventional and drought tolerant maize hybrids. Improved understanding of this important symbiosis under future climate change could potentially lead to more sustainable farming practices and increased primary food production.