Artificial mycorrhization modified vegetative growth, water use efficiency and photosynthetic performance of grapevine leaves

Abstract

Arbuscular mycorrhiza (AM) fungi are very important for life of plant communities and also a predominant factor in sustainable agro-ecosystems like viticulture. Grapevine is a facultativ mycotroph host of various AM fungi. Although many studies have examined the role of AM fungi in water relations and photosynthetic performance of different host plants, there is no such information in the case of mycorrhiza inoculated grapevine.

In the present study, we report the effects of applying an AM fungal inoculum (5 Glomus spp.) on a powdery and downy mildew resistant grapevine hybrid. One-year-old vines of a new resistant white variety (01-1/852) were investigated in pot (5L) experiment. Vines were grafted on two different rootstock varieties T5C and Fercal and planted in fertile and autoclaved soil. AM inoculation was performed simultaneously and 45 days after potting.

Simultaneously AM inoculation increased the proportion of infected roots with 10-12% compared to the control. Arbusculum richness of colonized roots showed a higher amount in case of autoclaved soil than in fertile soil. Mycorrhizal colonization of rootstock variety T5C was higher compared to Fercal. The most vigorous shoot growth (shoot length, leaf area, biomass weight) were found at vines growing in autoclaved soil and inoculated with AM fungi 45 days after planting independently of the rootstock variety applied.

We also determined how the AM symbiosis alters basic correlation between stomatal conductance and intrinsic water use efficiency (WUEi). Changes in maximal quantum yield and non-photochemical quenching (NPQ) based on rapid light curves (RLCs) of chlorophyll fluorescence in the leaves were also investigated. Close correlation was found between stomatal conductance and WUEi in both AM inoculated and control vines. Nevertheless, AM symbiosis resulted in significantly lower WUEi compared to the control. Lower WUEi indicates more favourable water relations of vines in both rootstock varieties. Analysis of RLCs showed higher values of NPQ by vines growing in autoclaved soil.