Growth and physiological responses of grape (Vitis vinifera “Combier”) to excess zinc

Abstract

Cuttings of Vitis vinifera (cultivar Combier) were exposed to seven different zinc (Zn) concentrations (control, 3.5, 7.0, 14.0, 21.0, 28.0, and 35.0 mM) to investigate growth and physiological responses to excess amount of zinc (Zn). The apparent plant growth, as indicated by daily height growth, daily stem diameter variation, and biomass accumulation, was increased by 3.5–7.0 mM surplus Zn addition. Coupled with the increase in plant growth, grape retained low level of leaf Zn concentration, and also retained high level of leaf iron concentration due to increasing translocation of iron (Fe) from root and shoots to leaves. Leaf N and K were increased or found at a constant high level, paralleling with low oxidative pressure and enhanced catalase (CAT) activity. Moreover, plant growth was depressed under high Zn levels (>14.0 mM). Generally excess Zn was stored in the non-sensitive plant parts (roots and shoots), and it caused significant reductions of P, Fe, Mn, Cu in different parts of plant. At the same time, excess Zn caused a pronounced increase in abscisic acid concentration. Our results showed that cultivar Combier is a highly Zn-tolerant grape cultivar and could be used as pioneer plants in metalliferous site and in acidic soil of the tropical and subtropical area.