三种山茶属植物的木材解剖学研究

Wood Anatomy Research of Three Plants of Camellia L.

摘要: 为更好地识别山茶属(Camellia L.)大苞白山茶(Camellia granthamiana Sealy)、杜鹃叶山茶(Camellia azalea C. F. Wei)及茶梅(Camellia sasanqua Thunb.)的木材解剖学特征，本文从植物树皮、木材宏观及微观构造进行了详细观测。研究表明：树皮：大苞白山茶干燥时灰白色；光滑，纵向裂纹肉眼下不明显，偶见有瘤状小突起；杜鹃叶山茶和茶梅干燥时分别为褐色和棕色；粗糙，纵向裂纹明显。三者树皮较薄，厚度约0.5 mm，心边材区别不明显；有或略有光泽；无气味和滋味；生长轮略明显；髓心黄色至金黄色，具有白色内含物，富含晶体；轴向薄壁组织无或不明显。大苞白山茶为散孔材至似半环孔材，单管孔或短径列复管孔(多为2个，稀3个)，杜鹃叶山茶和茶梅为散孔材，以单管孔为主，其次短径列复管孔(多为2个)；管孔形状呈不规则多角形或椭圆形、近圆形；管间纹孔式梯列，数目甚多，220~390个/mm2，径切面上明显，弦切面上可见；导管分子穿孔板横列，偶见斜列。木射线：非叠生，以异形I型为主，其次为异形III型(大苞白山茶)、异形单列(杜鹃叶山茶和茶梅)，常见多列射线融成单列；木射线密度(大苞白山茶15~20条/mm、杜鹃叶山茶和茶梅20~25条/mm)；射线宽度1~2细胞；射线高度(大苞白山茶5~15个细胞、杜鹃叶山茶3~30个细胞、茶梅2~36个细胞)；射线细胞较大，内含有树胶，常见巨型菱形、长方形或不规则形晶体，存在晶体的细胞常膨大；径切面上，横卧射线细胞垂直壁节状(其中大苞白山茶可见细胞核)；木纤维为纤维状管胞，在横切面上呈不规则多角形。髓心细胞呈圆形或椭圆形，边缘稍规则；细胞直径15~60 μm；大多细胞富含树胶；部分细胞富含晶体。综上所述，大苞白山茶与杜鹃叶山茶、茶梅的木材解剖结构具有较大差异，而后两者非常接近，与其他山茶属植物比较研究发现，差别较小。本研究旨在为该属植物的木材鉴定、系统分类和植物保护提供依据。

Abstract: In order to better identify the wood anatomical charac-teristics of Camellia granthamiana Sealy, Camellia azalea C. F. Wei and Camellia sasanqua Thunb., this paper has carried out detailed observation on the macro-structure and micro-structure of plant wood and bark. The experiment results indicated that: The bark of C. granthamiana was gray when dry; smooth, longitudinal crack not obvious under the naked eye, and occasionally with protuber-ances like tumor; the bark of C. azalea and C. sasanqua was sepia and brown respectively when dry; rough, longitudinal crack obvious. The bark of three species were relatively thin, with a thickness of about 0.5 mm, and the difference between the heart-sapwood was not obvious; wood with or slightly glossy, no smell or taste, the growth ring was slightly obvious, the pith was yellow to golden yellow with white inclusions and abundant crystals; Axial parenchyma was absent or not obvious. C. gran-thamiana: Diffuse-porous wood to near semi-ring-porous wood, Single pore or short radial multiple pore (mostly 2, rarely 3), C. azalea and C. sasanqua: Diffuse-porous wood, mainly single pore, sec-ondly short radial multiple pore (mostly 2); the shape of pore was irregular polygonal or elliptical, nearly round; Intervessel pitting scalariform, numerous, 220~390/mm2. It’s obvious on radial sec-tion and visible on tangential section; Perforation plate of vessel element transverse, occasionally oblique. The timber rays: Non-overlapping, mainly heterogeneous I type, secondly heterogeneous III type (C. granthamiana) or heterogeneous single type (C. azalea and C. sasanqua), multiple rays merge into a single commonly; timber ray density (C. granthamiana 15~20/mm, C. azalea and C. sasanqua 20~25/mm); timber ray width 1~2 cells; Timber ray height (C. granthamiana 5~15 cells, C. azalea 3~30 cells, C. sasanqua 2~36 cells); timber ray cells are large and contain gum, usually with giant rhombic, rectangular or irregular crystals, the cells with crystals are often enlarged; On radial section, vertically wall of recumbent ray cells are nodal (nucleus visible in C. granthamiana com-monly); Wood fibers are fibrous tracheids with irregular polygonal shapes in cross sections. Pith core cells round or elliptic, the edges lightly regular. Cell diameter 15~60 μm; Most cells are rich in gum; Some cells are rich in crystals. To sum up, the timber anatomical structure of C. granthamiana was quite different from that of C. azalea and C. sasanqua, the latter two were similar, compared with other camellia plants: The difference is small. The aim of this study was to provide a basis for the research on the wood identification, systematic classification and plant conservation.