The growth and mycorrhization of young Berberis microphylla G. Forst. plants are differently affected by organic and inorganic fertilizers, depending on the substrate

Abstract

Information regarding the relationship between fertilization, mycorrhizas, and plant growth is scattered for non-conventional productive plant species. We evaluated the effect of different substrates and fertilization treatments on growth and colonization by arbuscular mycorrhizas of young Berberis microphylla plants, a native Patagonian shrub with edible fruits. We conducted a greenhouse experiment based on two factors: substrate (conventional or native soil) and fertilization (no fertilization, organic fertilization, or inorganic fertilization). When plants were grown in conventional substrate, both fertilizers promoted growth, having the inorganic fertilizer a greater effect. The effect of both fertilizers was similar when plants were cultivated in native soil, and lesser than in conventional substrate. Plants grown in native soil were larger than those in conventional substrate when organic fertilizer or no fertilizer was applied, but this was reversed when inorganic fertilizer was applied. There was no mycorrhization on plants grown in conventional substrate. In native soil, mycorrhization was highest for non-fertilized plants (60.1%), followed by those with organic fertilization (40.4%), and lowest when inorganic fertilizer was applied (29.9%). The relative abundances of both vesicles and arbuscules showed the opposite tendency, having both their highest values in treatments with inorganic fertilizer. Mycorrhization was positively correlated with plant size, but only when fertilizers were applied. Based on our results, we hypothesized that fertilization reduce mycorrhization but select more beneficial mycorrhizal fungi. We concluded that organic fertilizers have a comparable effect to inorganic fertilizers in terms of promoting plant growth, accompanied by a lesser reduction of mycorrhization.