RUDERAL PLANTS: TEMPORARY HOSTS OF ARBUSCULAR MYCORRHIZAL FUNGI IN TRADITIONAL AGRICULTURAL SYSTEMS?

Abstract

Ruderal plants may serve as temporary hosts of arbuscular mycorrhizal fungi (AMF), by maintaining the availability of active propagules in the soil, which in turn favors rapid colonization of roots of cultivated species during the agricultural cycle. The goals of this study were to: 1) estimate the richness of ruderal plant species in an agricultural plot and determine their mycorrhizal status, 2) quantify the number of live AMF spores in soil samples, and 3) estimate the infection potential and number of active propagules in soil samples from the agricultural site. The agricultural site used was located in Yucatan, Mexico, and consisted of a monoculture of corn subjected to low-impact agricultural practices during the last five years. A total of 20 species of ruderal plants were found at the experimental site, belonging to 11 families. All the sampled species exhibited associations with AMF, and colonization percentages ranged from 11.7±0.07 to 79.6±0.01 among species. The rhizosphere presented an average of 565±324 spores in 50 g of dry soil, of which 58.76% of the spores were alive. The inoculum potential of the soil was 50.4±0.05%, while the number of infective propagules was 193.37 (both in 50 mL of soil). Results from this study show that the presence of ruderal species in agricultural sites may promote the maintenance of AMF communities by acting as temporary hosts of these fungal species. In doing so, ruderal species can favor a higher production of infective AMF propagules and thus stronger mycorrhizal interactions with cultivated species.