Lime-induced chlorosis of grapevine as affected by rootstock and root infection with arbuscular mycorrhiza and <i>Pseudomonas fluorescens</i>

Abstract

Grapevine cuttings (Vitis vinifera L. cv. Pinot blanc, clone VCR 5), grafted on 3309 C, a lime-susceptible rootstock, SO 4, a medium lime-tolerant rootstock and 41 B, a lime-tolerant rootstock, were grown in pots containing unsterilized calcareous soil. Before potting, the roots of the grafted plants were inoculated with a suspension of a mutant of Pseudomonas fluorescens and with the vesicular-arbuscular mycorrhizal (VAM! fungus Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe, in order to investigate the effect of these microorganisms on the severity of lime-induced chlorosis. The most significant findings were:

1. Pseudomonas fluorescens and Glomus mosseae treatments increased Fe and chlorophyll concentrations in the leaves and thus lime tolerance in plants grafted on 3309 C and 41 B;
2. the positive effect of VAM treatment was associated with increased levels of root infection and lower root growth;
3. the bacterial treatment improved the establishment of VAM fungi;
4. fruit quality of the susceptible graft combination raised to the level of untreated Pinot blanc/SO 4 vines due to the root treatments.