Abstract The relation between water-use and intercepted solar radiation depends on many factors involved in vine canopy architecture and physiology. In addition, vine productivity is related to the efficiency with which the intercepted photosynthetically active radiation (IPAR) is used, which in turn depends mainly on water availability and transport. In hedgerow-managed vines it exists the possibility to modulate IPAR by orienting their rows, influencing water-use efficiency (WUE), defined as dry matter produced by water used. Aiming to unravel the effects of row orientation on WUE, a three-year experiment was carried out in Valencia (Spain) on potted Vitis vinifera (L.) cv. Bobal and Verdejo with vine rows oriented either north-south (NS) or east-west (EW), under no-water restrictions. Simulated radiation interception over the growing seasons at the experimental plot showed an average 39% reduction in daily IPAR when EW was compared to NS. Vine transpiration was quantified by water balance, decreasing by 16% in Bobal and 8% in Verdejo when comparing EW against NS. In both cultivars, this reduction was 18% when considered relative to the total leaf area. Carbon assimilation was not markedly affected by row orientation. Therefore, since in both cultivars minor differences in vine performance occurred between orientations, WUE tended to increase by orienting the rows to the EW compared to NS. This resulted in most of the seasons an increase in water productivity calculated as grape yield/water-use ratio. Leaf gas exchange measurements partially agreed with the radiation interception simulations, suggesting a more complex regulatory mechanism and highlighting the importance of canopy microclimatic conditions in the physiological processes of hedgerow-managed crops. These findings encourage further research under field conditions and different soil water availabilities, aiming to optimize grapevine water productivity.

中文翻译：

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行向对盆栽葡萄性能和用水效率的影响

摘要 水分利用与截获的太阳辐射之间的关系取决于葡萄树冠层结构和生理学中涉及的许多因素。此外，葡萄树的生产力与截获的光合有效辐射 (IPAR) 的使用效率有关，而后者主要取决于水的可用性和运输。在树篱管理的葡萄树中，存在通过排列行来调节 IPAR 的可能性，从而影响用水效率 (WUE)，定义为用水产生的干物质。为了阐明行方向对 WUE 的影响，在瓦伦西亚（西班牙）对盆栽 Vitis vinifera (L.) cv. 进行了为期三年的实验。Bobal 和 Verdejo 的葡萄藤排列为南北 (NS) 或东西 (EW)，在无水限制下。当 EW 与 NS 相比时，在实验地块的生长季节模拟辐射拦截显示每日 IPAR 平均降低 39%。葡萄的蒸腾作用是通过水平衡来量化的，当比较 EW 和 NS 时，Bobal 减少了 16%，Verdejo 减少了 8%。在这两个品种中，相对于总叶面积而言，这种减少是 18%。碳同化不受行方向的显着影响。因此，由于在两个栽培品种中，葡萄藤的性能在不同方向之间发生了细微的差异，因此与 NS 相比，通过将行朝向 EW 定向，WUE 往往会增加。这导致大部分季节的水生产力增加，计算为葡萄产量/用水比。叶片气体交换测量与辐射拦截模拟部分一致，提出了一种更复杂的调节机制，并强调了冠层微气候条件在绿篱管理作物生理过程中的重要性。这些发现鼓励在田间条件和不同土壤可用水量下的进一步研究，旨在优化葡萄树的水分生产力。