Lammas shoots are flushes formed by some woody species later in the growing season. Having less time to develop, tissue formation is suggested to be incomplete leading to a higher peridermal water loss during consecutive months. In this study, we analysed morphological and anatomical parameters, peridermal conductance to water vapour and the level of native embolism in mid-winter and late-winter of lammas shoots and normal spring shoots of the apple varieties Malus domestica ‘Gala’ and ‘Nicoter’. Lammas shoots showed a significantly higher shoot cross-sectional area due to larger pith and corticular parenchyma areas. In contrast, phloem was significantly thicker in spring shoots. No pronounced differences were observed in xylem and collenchyma thickness or mean hydraulic conduit diameter. The phellem of spring shoots was composed of more suberinised cells compared to lammas shoots, which led to a significantly higher peridermal conductance in the latter. The amount of native embolism in mid-winter did not differ between shoot types, but in late-winter lammas shoots were more embolised than spring shoots. Data show that the restricted vegetation period of lammas shoots affects their development and, in consequence, their transpiration shield. This may also pose a risk for winter desiccation.

中文翻译：

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苹果树的冬季皮周电导：比较南美芽和春芽。

Lammas 枝条是由一些木本物种在生长季节后期形成的潮红。由于发育时间较短，建议组织形成不完整，导致连续几个月的皮下水分流失较多。在这项研究中，我们分析了形态解剖参数，peridermal导水蒸汽和本地栓塞在仲冬水平和收获节竹笋和苹果品种的正常春梢晚冬海棠斯蒂卡“晚会”和“尼古特”。由于较大的髓和皮质薄壁组织区域，Lammas 枝条显示出显着更高的枝条横截面积。相比之下，春笋的韧皮部明显更厚。在木质部和组织厚度或平均水力导管直径方面没有观察到明显差异。与 lammas 芽相比，春芽的 pellem 由更多的木栓质细胞组成，这导致后者的皮周电导率​​显着提高。仲冬的原生栓塞量在不同的枝条类型之间没有差异，但在晚冬的 lammas 枝条中栓塞的程度高于春枝。数据显示，南丫岛枝条受限制的植被期会影响它们的发育，进而影响它们的蒸腾作用。这也可能造成冬季干燥的风险。