Abstract：
With the increasing threat of global warming, the cultivation of wine grapes in high-altitude with cool-temperature climates has become a viable option. However, the precise mechanism of environmental factors regulating grape quality remains unclear. Therefore, principal component analysis (PCA) was utilized to evaluate the quality of wine grape (Cabernet Sauvignon) in six high-altitude wine regions (1987, 2076, 2181, 2300, 2430, 2540 m). Structural equation modeling (SEM) was applied for the first time to identify the environmental contribution to grape quality. The wine grape quality existed spatial variation in basic physical attributes (BP), basic chemical compositions (BC), phenolic compounds (PC) and individual phenols. The PCA models (variance > 85 %) well separate wine grapes from the six altitudes into three groups according to scores. The score of grapes at 2300 m was significantly high (3.83), and the grapes of 2540 m showed a significantly low score (1.46). Subsequently, the malic acid, total tannin, total phenol, titratable acid, total anthocyanin, and skin thickness were the main differing indexes. SEM model characterized the relational network of differing indexes and microclimatic factors, which showed that temperature and extreme air temperature had a greater direct effect on differing indexes than light, with great contributions from soil temperature (0.98**), day-night temperature difference (0.825*), and day air temperature (0.789**). Our findings provided a theoretical basis for grape cultivation management in high-altitude regions and demonstrated that the SEM model is a useful tool for exploring the relationship between climate and fruit quality.
摘要：
随着全球变暖的威胁越来越大,在凉爽气候的高海拔地区种植酿酒葡萄已成为可行的选择。然而,环境因子调控葡萄品质的确切机制尚不清楚。因此,主成分分析（PCA）用于评估六个高海拔葡萄酒地区（1987、2076、2181、2300、2430、2540m）的酿酒葡萄（赤霞珠）的质量。首次应用结构方程模型（SEM）来确定环境对葡萄品质的贡献。酿酒葡萄品质存在基本物理属性(BP)的空间变异,基本化学成分（BC），酚类化合物（PC）和单个酚。PCA模型（方差>85％）根据得分将六个海拔高度的酿酒葡萄很好地分为三组。2300米的葡萄得分明显较高（3.83），2540m的葡萄得分明显较低（1.46）。随后，苹果酸,总单宁,总酚,可滴定酸，总花色苷,和皮肤厚度是主要的不同指标。SEM模型表征了不同指标和小气候因素的关系网络，这表明温度和极端气温对不同指数的直接影响比光照更大，土壤温度的贡献很大(0.98**)，昼夜温差(0.825*),和日间空气温度（0.789**）。我们的发现为高海拔地区的葡萄栽培管理提供了理论依据，并表明SEM模型是探索气候与果实品质之间关系的有用工具。
