Fig 1.
(A) Mean daily temperature and cumulative growing degree days (GDD), (B) monthly rainfall, and (C) vapour pressure deficit (VPD) for the 2021 and 2022 seasons.
(A) Mean daily temperatures are indicated by blue circles for 2021, red triangles for 2022, and a purple dashed line for the average of the preceding eight years (2013‑2020). The purple shading indicates the temperature range over this period, and solid lines represent the GDDs. The maximum daily VPD is shown with blue circles for 2021 and red triangles for 2022 (C).
Table 1.
Comparison of treatment effects on vegetative growth and physiological parameters of V. vinifera cv. Chardonnay averaged over the 2021 and 2022 seasons.
Fig 2.
The evolution of leaf dry mass (2021, A; 2022, B) and leaf surface area (2021, C; 2022, D) of V. vinifera cv.
Chardonnay treated with a water control, an A. nodosum extract, an E. maxima extract, and an NPK‑Ref treatment. Each time‑series point represents the mean ± standard error (n = 12). Violin‑boxplots (central panels) show parameter distributions averaged across timepoints per season, with boxplot lines marking the 1st quartile, median, and 3rd quartile, the diamond indicating the mean and whiskers extending to 1.5 × the interquartile range. Different uppercase letters indicate significant differences based on EMMs between treatments during a season, averaged over Time (P < 0.05). Treatment application days are shown as dark blue bars on the x‑axis (DAA), the first treatment at 18 and 14 days before anthesis is omitted. Samples were taken on dry and clear days as far as possible; blue shading indicates periods with cool/cloudy conditions, and red shading denotes VPD stress (>3 kPa).
Fig 3.
The evolution of the leaf chlorophyll content index CCI (2021, A; 2022, B) the density of reaction centra per cross section RC∕CS (2021, C; 2022, D), the maximum quantum yield Fv∕Fm (2021, E; 2022, F) and the electron transport efficiency of photosystem II ΦE0 (2021, G; 2022, H) of V. vinifera cv. Chardonnay treated with a water control, an A. nodosum extract, an E. maxima extract, and an NPK‑Ref treatment.
Each time‑series point represents the mean ± standard error (n = 12). Asterisks indicate significance of the season level factors based on two‑way ANOVA (0.01 < P ≤ 0.05: *; 0.001 < P ≤ 0.01: **; P ≤ 0.001: ***; ns = not significant; see S4 Table for means separation by EMMs). Violin‑boxplots (central panels) show parameter distributions averaged across timepoints per season, with boxplot lines marking the 1st quartile, median, and 3rd quartile, and whiskers extending to 1.5 × the interquartile range. Different uppercase letters indicate significant differences based on EMMs between treatments during a season, averaged over Time (P < 0.05). When no letters are shown, a significant Treatment × Time interaction was present. Treatment application days are shown as dark blue bars on the x‑axis (DAA). Measurements were taken on dry and clear days as far as possible; blue shading indicates periods with cool/cloudy conditions, and red shading denotes VPD stress (>3 kPa).
Table 2.
Comparison of treatment effects at harvest on berry size and quality metrics of V. vinifera cv. Chardonnay for the 2021 and 2022 seasons.
Fig 4.
Berry volume (2021, A; 2022, B) and berry mass (2021, C; 2022, D) of V. vinifera cv. Chardonnay treated with water, an A. nodosum extract, an E. maxima extract, and an NPK‑Ref treatment.
Each time‑series point represents the mean ± standard error (n = 4). Asterisks indicate significance of the season level factors based on two‑way ANOVA (0.01 < P ≤ 0.05: *; 0.001 < P ≤ 0.01: **; P ≤ 0.001: ***; ns = not significant. Boxplots (central panels) show parameter distributions at harvest, with boxplot lines marking the 1st quartile, median, and 3rd quartile, and whiskers extending to 1.5 × the interquartile range. Different lowercase letters indicate significant differences between treatments at harvest, based on EMMs (P < 0.05). Different uppercase letters indicate significant differences based on EMMs between treatments during a season, averaged over Time (P < 0.05). Samples were taken on dry and clear days as far as possible; blue shading indicates periods with cool/cloudy conditions with rainfall.
Fig 5.
Development of titratable acidity–TA (2021, A; 2022, B), total soluble solids–TSS (2021, C; 2022, D) and berry sugar content (2021, E; 2022, F) of V. vinifera cv.
Chardonnay treated with a water control, an A. nodosum extract, an E. maxima extract, and an NPK‑Ref treatment. Each time‑series point represents the mean ± standard error (n = 4). Asterisks indicate significance of the season level factors based on two‑way ANOVA (0.01 < P ≤ 0.05: *; 0.001 < P ≤ 0.01: **; P ≤ 0.001: ***; ns = not significant. Boxplots (central panels) show parameter distributions at harvest, with boxplot lines marking the 1st quartile, median, and 3rd quartile, and whiskers extending to 1.5 × the interquartile range. Different lowercase letters indicate significant differences between treatments at harvest, based on EMMs (P < 0.05). Different uppercase letters indicate significant differences based on EMMs between treatments during a season, averaged over Time (P < 0.05). Samples were taken on dry and clear days as far as possible; blue shading indicates periods with cool/cloudy conditions with rainfall.
Fig 6.
Total number of clusters (A), average cluster mass (B) and average yield per vine (C) of V. vinifera cv.
Chardonnay treated with a water control treatment, an A. nodosum extract, an E. maxima extract, and an NPK‑Ref treatment (n = 12) for 2021 (empty violins) and 2022 (striped violins). Samples were taken at technical maturity (average of 21 °Brix). Shaded violin plots show the distribution of data, bar hinges represent quartile values, while whiskers extend to 1.5 × the inter quartile range and the sample mean is indicated with a white diamond. Treatments marked with an asterisk differed significantly from 2021 to 2022 based on their EMMs (P < 0.05).