摘要：
以成熟臭柏(Sabina vulgaris)为试验材料,使用徒手切片法观测臭柏鳞叶和刺叶的解剖结构,分析叶片解剖结构与其抗旱适应的关系,以揭示臭柏异形叶机制的生态意义,为臭柏在干旱半干旱地区植被恢复与重建中的推广应用提供理论依据.结果表明:(1)鳞叶角质层厚度极显著大于刺叶,而近轴面和远轴面的表皮系统厚度均极显著小于刺叶,说明鳞叶主要通过较厚的角质层防止水分散失,而刺叶主要通过较厚的整个表皮系统来保持水分.(2)鳞叶的气孔开张比、气孔开张度、气孔长度和宽度均极显著大于刺叶,而气孔密度极显著小于刺叶,说明鳞叶较耐旱,刺叶依赖较大的气孔密度和灵敏的气孔关闭来应对干旱胁迫.(3)鳞叶和刺叶的叶片厚度和主脉厚度无显著差异,但鳞叶的栅栏组织厚度、海绵组织厚度、栅/海、叶片组织紧密度和树脂道面积均显著或极显著大于刺叶,木质部厚度、木/维和叶片组织疏松度均极显著小于刺叶,说明鳞叶可通过较大的栅/海、紧密的叶片结构来适应干旱,而刺叶通过增强输导组织来应对干旱.研究认为,鳞叶忍耐干早能力较强,而相对鳞叶来说,刺叶主要通过逃避的方式来应对干旱.%Gathering mature trees as experimental materials,we observed the anatomical structure of scale and needle leaves of Sabina vulgaris by using the hand-sliced method.The aim is to explore the relationship between drought-resistant adaptation and anatomic structure of scale and needle leaves of S.vulgaris,to reveal the ecological significance of heterophylly mechanism of S.vulgaris,and to provide a theoretical basis on widespread use of vegetation restoration and reconstruction of S.vulgaris in the arid and semi-arid areas of China.The results show as followed,(1) corneum thickness (CT) of scale leaves was significantly higher than that of needle leaves,while the thickness of abaxial side epidermis(TAB) and adaxial side epidermis(TAD) of scale leaves were both significantly lower than those of needle leaves.That meant scale leaves mainly prevented water loss by thick cuticle,while needle leaves mainly maintain water through the whole thick epidermal system.(2) Opening stoma ratio (OS),stoma aperture(SA),stoma length (SL) and stoma width (SW) of scale leaves all were significantly higher than those of needle leaves,while stoma density (SD) of scale leaves was significantly smaller than that of needle leaves.The results showed that scale leaves had stronger drought tolerance,and needle leaves relied on higher SD and sensitive stomatal closure to react against drought stress.(3) Leaf thickness (LT) and midrib thickness (MT) of scale and needle leaves both had no significant difference,nevertheless thickness of palisade tissue (TP),thickness of spongy tissue (TS),palisade tissue and spongy tissue ratio (P/S),tightness of leaf palisade tissue (TLP) and area of resin duct (AR) of scale leaves all were significantly higher than those of needle leaves,and xylem thickness (XT),xylem thickness and midrib thickness ratio (X/M) and loose-ness of leaf spongy tissue (LLS) of scale leaves all were significantly less than those of needle leaves.The observed results indicate that scale leaves adapt to drought by higher P/S and compactness of leaf structure,while needle leaves react against drought by strengthening conducting tissue.The study showed that drought tolerance of scale leaves was stronger than that of needle leaves,and compared with scale leaves,needle leaves mainly chose an avenue of escape to react against drought.
