Mycorrhizae formation and nutrient uptake of new corn (Zea mays L.) hybrids with extreme canopy and leaf architecture as influenced by soil N and P levels

A study was conducted to evaluate the effect of N and P supply levels on my corrhizal formation and nutrient uptake in corn hybrids with different arch itectures and to determine arbuscular mycorrhizal fungal (AMF) development in relation to shoot N/P ratio and shoot:root ratio. Corn pot cultures with a pasteurized medium of two parts sand and one part sandy loam soil were g rown in the greenhouse. Marigold plants inoculated or not with Glomus intra radices Schenck & Smith were used to establish an AMF hyphal network in the designated soil pots. Corn hybrids were seeded after removal of the marigo ld plant. Mycorrhizal colonization of corn hybrids and the quantity of extr aradical hyphae produced in soil were greatest at the lowest P level and at the intermediate N level. Root colonization was correlated with shoot N/P ratio only at the intermediate N level. The shoot concentrations of P, Mg, Zn and Cu were significantly higher in mycorrhizal plants than in non-mycor rhizal plants. The corn phenotype with the highest shoot:root ratio had the highest root colonization. The corn hybrid with a leafy normal stature arc hitecture had a greater mycorrhizal colonization than that of other two cor n hybrids. This experiment showed that N level in soil influenced shoot N/P ratio, root colonization and extraradical hyphal production, which in turn influenced uptake of other nutrients.