Mycorrhization alleviates salt stress in grape rootstocks during in vitro acclimatization

An in vitro experiment was conducted to achieve arbuscular mycorrhizal fungus (AMF) root colonization in micro-propagated grape rootstocks Salt Creek (Vitis champini) and Male hybrid (Vitis vinifera) during acclimatization and also to study the effect of AMF on alleviating salt-stress. The plantlets were grown in potting medium containing peat: vermiculite: perlite (2:1:1). In the salt-stressed medium, mycorrhizal root colonisation was significantly higher in Male hybrid (19%) than in Salt Creek (12%) rootstock. Mycorrhizal plantlets had significantly higher root (40%) and shoot (20%) dry biomass production than non-mycorrhizal plantlets raised on saline medium. The total chlorophyll (TC) content was higher in the leaves of mycorrhizal as compared to uninoculated plantlets of Salt Creek (24%), had higher TC contents than Male hybrid (17%). Mycorrhizal tissue had significantly higher levels of P, K, Ca and Mg in addition to higher Na⁺ and Cl⁻concentrations than non-mycorrhizal plantlets. Under saline conditions, Salt Creek showed a high degree of dependence on mycorrhizae, than Male hybrid. The reduction in Na⁺/K⁺ ratio together with a concomitant increase in P, K, Ca and Mg absorption and high chlorophyll and proline contents in mycorrhizal plantlets may be important salt-alleviating mechanisms for plants growing in saline soils, like observed in Salt Creek rootstock.