San Luis (Chile Ancho pepper) with a Mixed Glomus spp. from Mexico and Glomus intraradices

Abstract

The effect of a mixed isolate of arbuscular mycorrhizal (VAM) fungi [Glomus spp. from Veracruz, Mexico] and a pure isolate of Glomus intraradices was assessed on the growth and gas exchange of `Chile Ancho' (Capsicum annuum L. cv. San Luis) under phosphorus (P) stress. The experiment was carried out under glasshouse conditions in 1-L plastic pots containing a pasteurized mixture of 1 sand: 1 sandy loam (v/v). Plants were inoculated or noninoculated with VAM. Plants were fertilized with a modified Long Ashton nutrient solution (LANS) containing 0 or 11 (g phosphorus/ml). Gas exchange measurements were taken 21 and 70 days after the experiment was initiated. Mycorrhizal plants at both 0 and 11 (g P/ml) had greater leaf area, fruit, root, stem and leaf dry mass, and a lower specific leaf area and root/shoot ratio than nonmycorrhizal plants. Nonmycorrhizal plants not supplied with P had a higher leaf area ratio than plants colonized with G. intraradices. Net photosynthesis and stomatal conductance were not consistent with growth responses. There were no significant differences in growth and gas exchange between the two mycorrhizal isolates.