This study is focused on the internal structure of leaf midrib (rachis) of some male tress of certain date palm cultivars, namely Khalas, Naboat-Saif, Sillej and Sukkary, common to Saudi Arabia. It takes into consideration the structure, dimension and abundance of vascular bundles (VBs), vessel lumen diameter, relative proportion of fibers and vessels in the vasculature at the basal and the middle parts along the length of the rachis. A large number of conjoint, collateral and closed VBs of varying sizes, embedded in the parenchymatous ground tissue, are normally present. The xylem in the VB often contains 6–15 protoxylem and 2–3 metaxylem vessels as seen in cross-sectional view. Vascular bundles have fiber caps, of which the upper ones were quite thicker than the lower (inner) ones in general. Cultivars Khalas and Sukkary are superior in having the highest midrib cross-sectional area (17.1 cm 2 and 16.8 cm 2 , respectively). Moreover, Khalas have the highest fiber area fraction (17% and 25%), while Sukkary a highest vessel density (16–17 per VB) in both the basal and middle positions at the rachis. Cultivar Naboat-Saif is superior in having a high VB density (130 and 194 per cm 2 ), narrowest vessels (42.4 µm and 53.5 µm) and thickest vessel wall (4.23 µm and 4.45 µm, respectively) both in the basal and in the middle position of the rachis length.

中文翻译：

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枣椰树轴作为木材复合工业的原料：解剖学特征

本研究的重点是沙特阿拉伯常见的某些枣椰树品种的一些雄性发束（即 Khalas、Naboat-Saif、Sillej 和 Sukkary）的叶中脉（轴）的内部结构。它考虑了维管束 (VB) 的结构、尺寸和丰度、血管腔直径、脉管系统中沿轴长度的基底和中部的纤维和血管的相对比例。通常存在大量不同大小的联合、侧支和闭合的 VB，它们嵌入实质的基底组织中。VB 中的木质部通常包含 6-15 个原木质部和 2-3 个后木质部血管，如横截面视图所示。血管束具有纤维帽，其中上部的纤维帽通常比下部（内部）的纤维帽厚得多。栽培品种 Khalas 和 Sukkary 的优势在于具有最高的中脉横截面积（分别为 17.1 cm 2 和 16.8 cm 2 ）。此外，Khalas 的纤维面积分数最高（17% 和 25%），而 Sukkary 的血管密度最高（每个 VB 16-17）在轴的基底和中间位置。栽培品种 Naboat-Saif 的优势在于具有高 VB 密度（130 和 194 每 cm 2 ）、最窄的血管（42.4 µm 和 53.5 µm）和最厚的血管壁（分别为 4.23 µm 和 4.45 µm）在基底和基底中轴长的中间位置。