Fungos micorrízicos em mudas de Jatropha curcas L. submetidas a estresse hídrico

Abstract

The water deficit is a limiting factor to the growth of the plants, being one of the main causes of the low productivity in crops. Physic nut, Jatropha curcas L. is a species that has a wide adaptation to edaphoclimatic conditions, especially to drought. The mycorrhization technique is an alternative to contribute and increase its production under these conditions. Therefore, this work aims to evaluate the morphophysiological development of seedlings of J. curcas in association with different arbuscular mycorrhizal fungi submitted to stress due to water deficit. Three species were isolated from arbuscular mycorrhizal fungi: (M1) Gigaspora albida (M2) Claroideoglomus etunicatum, (M3) Rhizophagus intraradices and a nonmycorrhized control treatment (M0), and presence (C) and (E) absence of irrigation. The jatropha seeds were planted and previously inoculated with mycorrhizal fungi in the absence of water stress. Morphological data (height, collection diameter, number of leaves and leaf area) were measured. Physiological evaluations, as well as root, shoot and total biomass. The plants inoculated with C. etunicatum species showed higher height, number of leaves, stem diameter and leaf area, in addition, seedlings inoculated with C. etunicatum and R. intraradices showed a larger increase in dry mass production. Seedlings of J. curcas inoculated with the species C. etunicatum and R. intraradices maintained rates of stomatal conductance, transpiration, photosynthetic rate and SPAD index, higher under water deficit than those not inoculated. Both the maximum photochemical efficiency of PSII (Fv / Fm) and the effective quantum efficiency of PSII (ΦPSII) were not affected by water suppression in the presence or absence of arbuscular mycorrhizal fungi. In addition, both species C. etunicatum and R. intraradices presented medium mycorrhizal dependence. Therefore, the inoculation of mycorrhizae C. etunicatum and R. intraradices allows a greater development of the meager jatropha under conditions of water deficit.