Agronomical and Environmental Factors Influence Root Colonization, Sporulation and Diversity of Arbuscular Mycorrhizal Fungi at a Specific Phenological Stage of Banana Trees

摘要

The present research studied the influence of agronomical practices and seasonal changes on intraradical colonization and spore production patterns of Arbuscular Mycorrhizal Fungi (AMF) of Grand Nain banana clone plantations with contrasting management. It was studied if root colonization, spore production and spore diversity were determined by management and environmental changes. Roots and rhizosphere soil samples from Grand Nain banana plants at the fruiting phenological state were collected, fortwo years, at the beginning of the rainy season, the rainy season and during the dry season. Lower root colonization percentages, spore numbers and spore diversity indexes were found in the plantation that used an excess of Agrochemicals (AC), independent from the season. Root colonization was higher in the dry season and, to a lower extent, at the beginning of the rainy season than at the rainy season. The number of spores remained constant in the plantation AC while, in the low input management culture plantation (LI), an increment was observed when passing from the rainy season to the beginning of the following rainy season. Both plantations presented the following four dominant AMF spore types: Glomus (GC-1Ban), Glomus (GC-2Ban), Acaulospora (AH-1Ban) and Sclerocystis (SN-1Ban), where Glomus GC-1Ban was the most abundant type. The independent effect of agronomical management and environmental factors on root colonization, spore production and diversity was thus confirmed in plants sampled at thesame phenological stage. This is further evidence suggesting multiple external control factors on the development and propagation of AMF, which may eventually affect the functioning of the symbiosis in field conditions.