Abstract Lenticels are sites of preferential gas exchange and water loss. Here we quantified the water vapor permeance of lenticels and their contribution to total transpiration in different regions of the apple (Malus × domestica Borkh.) fruit skin. Along the transect pedicel to calyx, lenticel area decreased (smaller lenticels), while lenticel density per unit area and cumulative lenticel area both increased. Lenticel density was highest in ‘Renoirciv’ (13.6 ± 0.5 cm−2 in the cheek region) followed by ‘Wellant’ (6.9 ± 0.5 cm−2 in the cheek region) apple. About 10 % of lenticels had microcracks as indexed by infiltration by a solution containing a silicone surfactant. There was no infiltration in the absence of the surfactant. In ‘Wellant’ the relative contribution of lenticellular water loss to the total was lower in the pedicel region (14 %) than in the calyx region (25 %). The contribution of lenticels differed among cultivars averaging in the cheek region 19 % in ‘Wellant’ and 8 % in ‘Pinova’ apple. The permeance of the periderm of a lenticel exceeded that of a russeted fruit skin 5.8-fold in ‘Wellant’ and 5.2-fold in ‘Pinova’. Skin permeance was positively and significantly related to both lenticel density and cumulative lenticel area within a region or between regions in ‘Wellant’. Across nine apple cultivars, permeance was significantly and positively related to lenticel density ( r2 = 0.52*) and to cumulative lenticel area ( r2 = 0.84***). The mechanistic basis for the increased water vapor permeability of lenticels is discussed.

中文翻译：

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皮孔和苹果果实蒸腾作用

摘要 皮孔是优先气体交换和失水的场所。在这里，我们量化了皮孔的水蒸气渗透率及其对苹果（Malus ×domestica Borkh.）果皮不同区域总蒸腾作用的贡献。沿断面花梗到花萼，皮孔面积减少（皮孔变小），而单位面积皮孔密度和累积皮孔面积均增加。'Renoirciv'（脸颊区域为 13.6 ± 0.5 cm-2）的扁豆密度最高，其次是“Wellant”（脸颊区域为 6.9 ± 0.5 cm-2）苹果。大约 10% 的皮孔具有微裂纹，这通过含有有机硅表面活性剂的溶液的渗透来指示。在没有表面活性剂的情况下没有渗透。在“Wellant”中，花梗区域（14 %）的豆状细胞失水对总量的相对贡献低于花萼区域（25 %）。皮孔的贡献在不同品种之间不同，在'Wellant' 和'Pinova' 苹果的脸颊区域平均分别为 19% 和 8%。皮孔周皮的渗透性在'Wellant'和'Pinova'中超过了赤褐色果皮的5.8倍和5.2倍。皮肤渗透性与“Wellant”区域内或区域之间的皮孔密度和累积皮孔面积呈显着正相关。在九个苹果品种中，渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。皮孔的贡献在不同品种之间不同，在'Wellant' 和'Pinova' 苹果的脸颊区域平均分别为 19% 和 8%。皮孔周皮的渗透性在'Wellant'和'Pinova'中超过了赤褐色果皮的5.8倍和5.2倍。皮肤渗透性与“Wellant”区域内或区域之间的皮孔密度和累积皮孔面积呈正显着相关。在九个苹果品种中，渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。皮孔的贡献在不同品种之间不同，在'Wellant' 和'Pinova' 苹果的脸颊区域平均分别为 19% 和 8%。皮孔周皮的渗透性在'Wellant'和'Pinova'中超过了赤褐色果皮的5.8倍和5.2倍。皮肤渗透性与“Wellant”区域内或区域之间的皮孔密度和累积皮孔面积呈显着正相关。在九个苹果品种中，渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。皮孔周皮的渗透性在'Wellant'和'Pinova'中超过了赤褐色果皮的5.8倍和5.2倍。皮肤渗透性与“Wellant”区域内或区域之间的皮孔密度和累积皮孔面积呈显着正相关。在九个苹果品种中，渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。皮孔周皮的渗透性在'Wellant'和'Pinova'中超过了赤褐色果皮的5.8倍和5.2倍。皮肤渗透性与“Wellant”区域内或区域之间的皮孔密度和累积皮孔面积呈显着正相关。在九个苹果品种中，渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。渗透性与皮孔密度 (r2 = 0.52*) 和累积皮孔面积 (r2 = 0.84***) 呈显着正相关。讨论了提高皮孔水蒸气渗透率的机理基础。