Arbuscular-mycorrhizal fungi alleviate transplantation shock in micropropagated grapevine (Vitis vinifera L.)

Abstract

SummaryThe effects of root inoculation with seven different arbuscular-mycorrhizal fungi (AMF) (Acaulospora laevis, A. scorbiculata, Entrophospora colombiana, Gigaspora gigantea, Glomus manihotis, Scutellospora heterograma) and a commercial mixed inoculum (consisting of Glomus moessae, G. manihotis and Gigaspora gigantea) on tissue culture-derived grapevine plantlets were studied during the hardening stage, under glasshouse conditions. Sixty days after inoculation, the percentages of plantlet survival, vine lengths, plant fresh and dry weights, leaf areas, photosynthetic rates, total chlorophyll contents, proline concentrations, nitrate reductase activities and nutrient status were determined. AMF-treated plantlets were superior to control plantlets for all parameters measured. Ex vitro survival rates of micropropagated grapevine plantlets were almost doubled as a result of AMF-inoculation. Correlations were calculated between the extent of root colonisation by AMF and the different parameters.Among the physiological and growth parameters, the highest positive correlation (r = 0.852) was noted for photosynthetic rate, followed by leaf area (r = 0.839). Among the biochemical parameters, the highest correlation was with proline content (r = 0.979) followed by nitrate reductase activity (r = 0.865). For nutrient status, the maximum correlation was between with AMF-colonisation and Zn (r = 0.880), followed by P (r = 0.835). With respect to the different parameters studied, A. laevis, G. manihotis and the mixed inoculum were identified as the most effective inocula. Our results indicated that AMF-colonisation could be an efficient technique to reduce the shock of transplantation for in vitro-raised grapevine plantlets for commercial use.