The reproductive phenology of Acaena elongata and its relation with arbuscular mycorrhizal fungi

Plant sexual reproduction is an energetic process since it requires large amounts of resource allocation for flower and fruit production. Therefore, the establishment of a mutualism with arbuscular mycorrhizal (AM) fungi can increase the plant’s reproductive success. Acaena elongata is a native weed and a plant species indicator of anthropogenic perturbations in the understory of Abies religiosa forests of the Magdalena river basin in Mexico City. The aim of this work was to assess whether: i) there are temporal and spatial variations in AM fungal root colonization in A. elongata, ii) AM fungal root colonization is linked to A. elongata flower and fruit production patterns, and iii) AM fungal root colonization, spore abundance and richness, and A. elongata reproductive phenology are related to soil variables. Eight plots were established with five randomly selected individuals of A. elongata. Over the course of 1 year, the A. elongata reproductive phenology, environmental temperature, and relative soil moisture were registered monthly. Additionally, root samplings for AM fungal colonization and soil for determining the AM fungal spore abundance and richness were carried out during the rainy and dry seasons. The mean total AM fungal root colonization percentage was higher in the dry season (78 ± S.E. 11.09%) than in the rainy season (71 ± S.E. 13.2%); A. elongata showed reproductive structures throughout the year, with negative significant correlations between colonization and some phenological phases during the rainy season. Flower and fruit production as well as AM fungal root colonization were related to variations in the abiotic variables in each season and population. This study contributes to the understanding of the relationship between AM fungi and a plant species indicator of anthropogenic perturbations.