Physiological Responses and Visual Quality of Perennial Ryegrass (Lolium perenne L.) Influenced By Mycorrhizal Infection and Humic Acid.

Studies have shown that Arbuscular mycorrhizal fungi (AMF) symbiosis has been beneficial to host plants. These include improved plant growth and development, nutrients absorption and metabolism. It has been reported  that  majority of grass species form an AM symbiosis. A Randomized Complete Block design experiment with 4 replications was conducted to evaluate the effects of two AM fungi (Glomus intraradices and G. mosseae) in the presence of different humic acid (HA) spray treatments (0, 100, 400, and 1000 mgL^-1) on various nutrients (N, P, K, Fe and Zn) uptake, visual quality and root growth and architecture, and colonization of “Speedygreen” perennial ryegrass. Results showed HA did not affect plant growth significantly, however, AMF colonization improved dry and fresh weights. Mycorrhizal inoculations significantly increased visual quality. AMF inoculation and HA treatment resulted in improved root architecture rather than root biomass production. Neither HA treatments nor mycorrhizal inoculation affected leaves N and Fe contents; however P, K and Zn concentrations improved by AM inoculation. More roots were colonized by G. intraradices than G. mosseae. These results suggest that AM inoculation is beneficial in enhancing some nutrients uptake and root development of ryegrass and may lead to less fertilizer input.