Severe prebloom leaf removal dramatically affects the source-sink balance in grapevines, leading to a reduction in fruit set. In this study, carried on for two consecutive years, the impact of defoliation at bloom was evaluated with the objective to assess the capacity of developing inflorescences to attract photosynthates from adjacent shoots subjected to varying source/sink manipulations. In Pinot noir trained to a bilateral cordon, untreated vines (UT-UT) were compared to a treatment where shoots on one-half of the vines were subjected to the removal of 10 basal leaves at bloom (UT-LR). Another set of vines underwent sink removal (inflorescences and shoot apex) at bloom on half of the shoots by hand thinning (TFR-UT). A final treatment consisted of removing 10 basal leaves on half of the shoots and removing sinks on the other half of the canopy (TFR-LR). Following treatment application, shoot leaf area retained was ~40% of the total in UT-LR and TFR-LR. UT-LR reduced the whole canopy leaf area available per inflorescence by ~44% when compared to UT-UT. TFR-LR did not affect this balance. In UT-LR, fruit set was significantly reduced (-36% as compared to UT-UT), whereas it was unaffected by TFR-LR and TFR-UT. Independent of treatments, fruit set in both seasons was correlated with whole-canopy leaf area per inflorescence at bloom and not with the single shoot leaf area retained after early leaf removal.

中文翻译：

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Bloom 时的整个树冠源汇平衡决定了 cv. 中的水果集。黑比诺早期去叶

严重的开花前叶片去除会显着影响葡萄藤的源库平衡，导致坐果减少。在这项连续两年进行的研究中，评估了开花时落叶的影响，目的是评估发育中的花序吸引来自受到不同源/汇操作的相邻枝条光合产物的能力。在双侧警戒线训练的黑比诺中，将未经处理的葡萄藤 (UT-UT) 与其中一半葡萄藤上的枝条在开花时去除 10 片基生叶 (UT-LR) 的处理进行比较。另一组葡萄藤在开花时通过手工疏伐 (TFR-UT) 去除一半的枝条上的水槽（花序和枝条顶端）。最后的处理包括去除一半枝条上的 10 片基生叶和去除树冠另一半上的水槽 (TFR-LR)。处理应用后，保留的芽叶面积是 UT-LR 和 TFR-LR 总面积的 40%。与 UT-UT 相比，UT-LR 将每个花序可用的整个冠层叶面积减少了约 44%。TFR-LR 不影响这种平衡。在 UT-LR 中，坐果显着减少（与 UT-UT 相比为-36%），而不受 TFR-LR 和 TFR-UT 的影响。独立于处理，两个季节的坐果与开花时每个花序的整个冠层叶面积相关，而不与早期去除叶子后保留的单芽叶面积相关。与 UT-UT 相比，UT-LR 将每个花序可用的整个冠层叶面积减少了约 44%。TFR-LR 不影响这种平衡。在 UT-LR 中，坐果显着减少（与 UT-UT 相比为-36%），而不受 TFR-LR 和 TFR-UT 的影响。独立于处理，两个季节的坐果与开花时每个花序的整个冠层叶面积相关，而不与早期去除叶子后保留的单芽叶面积相关。与 UT-UT 相比，UT-LR 将每个花序可用的整个冠层叶面积减少了约 44%。TFR-LR 不影响这种平衡。在 UT-LR 中，坐果显着减少（与 UT-UT 相比为-36%），而不受 TFR-LR 和 TFR-UT 的影响。独立于处理，两个季节的坐果与开花时每个花序的整个冠层叶面积相关，而不与早期去除叶子后保留的单芽叶面积相关。