Yu Runze, Kurtural S Kaan
Department of Viticulture and Enology, University of California, Davis, Davis, CA, United States.
Front Plant Sci. 2020 Mar 11;11:244. doi: 10.3389/fpls.2020.00244. eCollection 2020.
The majority of the wine grapes are grown in Mediterranean climates, where water is the determining factor for grapevine physiology and berry chemistry. At the vineyard scale, plant water status is variable due to the variability in many environmental factors. In this study, we investigated the ecophysiological variability of an irrigated Cabernet Sauvignon ( L.) vineyard. We used equidistant grid sampling to assess the spatial variations of the plants and soil, including plant water status by stem water potential (Ψ ), leaf gas exchange, and on-site soil analysis. We also measured soil electrical conductivity (EC) by proximal sensing at two depths [0.75 - 1.5 m (sub soil); 0 - 0.75 m (top soil)]. Ψ integrals were calculated to represent the season-long plant water status. On the base of realized Ψ integrals, the vineyard was delineated into two functional homogeneous zones (fHZs) with one severely water stressed zone and one moderately water stressed zone. Sub soil EC was directly related to Ψ ( = 0.56) and ( = 0.39) when the soil was proximally sensed at harvest in 2018. Although the same trend was evident in 2019 we could not deduce a direct relationship. The fruits from the two fHZs were harvested differentially. Comparing the two fHZs, there was no significant difference in juice total soluble solids or pH. The severely water stressed zone showed significantly higher malvidin and total anthocyanins on a dry skin weight basis, but lower peonidin, malvidin on a per berry basis in 2018. In 2019, there were more quercetin and total flavonols per berry in the severely water stressed zone. Overall, this study provided fundamental knowledge of the viability of managing spatial variability by delineating vineyard into distinct zones based on plant water status, and the potentiality of proximally sensed soil EC in the spatial assessment of plant water status and the supporting of vineyard management.
大多数酿酒葡萄种植在地中海气候区，在那里水分是葡萄树生理和浆果化学的决定性因素。在葡萄园尺度上，由于许多环境因素的变异性，植物水分状况是可变的。在本研究中，我们调查了一个灌溉赤霞珠葡萄园的生态生理变异性。我们使用等距网格采样来评估植物和土壤的空间变化，包括通过茎水势（Ψ ）评估植物水分状况、叶片气体交换以及现场土壤分析。我们还通过近感测量在两个深度[0.75 - 1.5米（底土）；0 - 0.75米（表土）]测量土壤电导率（EC）。计算Ψ 积分以代表整个生长季的植物水分状况。基于实测的Ψ 积分，葡萄园被划分为两个功能同质区（fHZs），一个是严重水分胁迫区，一个是中度水分胁迫区。2018年收获时近感测量土壤时，底土EC与Ψ （ = 0.56）和 （ = 0.39）直接相关。尽管2019年有相同趋势，但我们无法推断出直接关系。来自两个fHZs的果实分别采收。比较两个fHZs，果汁总可溶性固形物或pH值没有显著差异。在2018年，严重水分胁迫区以干皮重计矢车菊素和总花青素显著更高，但以单粒浆果计芍药色素、矢车菊素更低。2019年，严重水分胁迫区单粒浆果中槲皮素和总黄酮醇更多。总体而言，本研究提供了关于根据植物水分状况将葡萄园划分为不同区域来管理空间变异性的可行性的基础知识，以及近感测量土壤EC在植物水分状况空间评估和葡萄园管理支持方面的潜力。
