Influence of genetic, ontogenetic, and climatic factors on pressure-volume curve traits of grapevines (Vitis vinifera L.): A quantitative synthesis

Abstract

Understanding how grapevines respond to water stress is crucial for adapting viticulture to increasingly variable climatic conditions (Chaves et al., 2010). The analysis of pressure–volume (P–V) curves provides key physiological traits of drought response: the osmotic potential at full turgor (π_o), the turgor loss point (π_tlp) and the relative water content at the turgor loss point (RWC_tlp), the modulus of elasticity (ε), and the apoplastic fraction (a_f) (Alsina et al., 2007; Hochberg et al., 2017). It has been suggested that cultivars from diverse climatic origin are equally capable to adjust their osmotic potential to shifting environmental conditions (Sinclair et al 2024). Thus, P–V traits may be too variable within genotypes to be used for phenotyping the drought responses of grape cultivars. In order to assess the validity of P–V as indicators of drought responses, we quantified the influence of cultivar, rootstocks, climate and irrigation regimes on the traits of 11 grape cultivars. We conducted a quantitative synthesis using datasets from multiple experimental campaigns in vineyards located in Catalonia (NE Spain). We evaluated the relative contribution of genetic, ontogenetic, and climatic factors to the variability in P–V traits. Also, we performed an analysis on the variety Macabeu with two field trials: (1) an irrigation experiment, and (2) a rainfed experiment testing different rootstocks. Over multiple sites and seasons, we found that the variance of P–V traits was largely explained by ontogenetic (intra-seasonal) changes, but with significant contributions of genetics and spatiotemporal differences in climate. Within-variety analyses helped as narrow down the effects of ontogeny, environment, and their interaction. In irrigated vines, there was a stronger decline in π_o and π_tlp as the season progressed, compared to rainfed vines. ε values remained lower in the irrigated treatment. In the rootstock experiment, RWCₜₗₚ showed significant temporal changes. Among them, 1103P, 110R, M2 and 140RU exhibited a reduction between veraison and harvest, while M4 maintained more stable values. Differences among rootstocks were limited, suggesting that RWCₜₗₚ was only weakly influenced by rootstock genotype under rainfed conditions. Overall, the P–V traits are highly plastic, showing the ability of vines to adapt their physiology to rapidly changing environmental conditions. Nonetheless, noticeable cultivar-specific differences suggest that certain genotypes may better adapted to cope with drought. P–V traits are thus indicators of cultivar-specific drought responses, but their characterisation requires measurements over complete seasons and contrasting environmental conditions.

References

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