Water status and must composition in grapevine cv. Chardonnay with different soils and topography and a mini meta-analysis of the δ13 C/water potentials correlation

Abstract

Background: The measurement of carbon isotopic discrimination in grape sugars at harvest (δ¹³ C) is an integrated assessment of water status during ripening. It is an efficient alternative to assess variability in the field and discriminate between management zones in precision viticulture, but further work is needed to completely understand the signal.

Results: This work, spanning over 3 years, performed in a hillslope toposequence in Burgundy, delineates the relationships between main soil properties (gravel amount, slope, texture) and the grapevine water status assessed by δ¹³ C. The highest δ¹³ C, indicating most severe water deficit, was recorded in gravelly soils on steep slopes. The amount of sugars and malic and tartaric acids was also related to δ¹³ C. The relationship between δ¹³ C and predawn leaf water potentials (Ψ_pd ) was also investigated, because the absolute values of measured δ¹³ C were lower than the values currently found in the literature.

Conclusions: A mini-meta-analysis was performed, which showed that the slope of the relationships between minimum Ψ_pd and δ¹³ C was stable across studies (a change of 1‰ in δ¹³ C corresponded to a change of -0.2 MPa in the minimum Ψ_pd ), while the intercept of the comparison δ¹³ C/Ψ_pd changed, probably because of genetic variations between varieties, or environmental differences. © 2017 Society of Chemical Industry.

Keywords: Vitis vinifera; carbon isotopic discrimination; slope; terroir; water stress.