【作者】 周亚福； 刘文哲；

【Author】 Ya-Fu Zhou, Wen-Zhe Liu Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Eductation, School of Life Science of Northwest University, Xi ’an, 710069, China

【机构】 西部资源生物与现代生物技术教育部重点实验室西北大学生命科学学院；

【摘要】 白鲜(Dictamnus dasycarpus Turcz.)隶属于芸香科白鲜属,为多年生宿根草本植物,分布东至我国东北,东南至我国江西北部,为重要的药用植物。利用组织化学、光学显微镜、扫描和透射电子显微镜技术研究了白藓分泌组织及其非腺毛的形态、分布和发生发育规律,进一步探讨了几种类型分泌组织与非腺毛的系统演化关系。白鲜具有分泌囊、头状腺毛和囊状腺毛3类分泌组织,另外还分布有一种非腺毛。分泌囊仅出现在叶中,主要分布于靠近叶片上表皮的叶肉组织中,在紧贴叶片下表皮的叶肉组织中偶有分布;成熟分泌囊由鞘细胞和一层上皮细胞围绕的圆形腔隙构成,上皮细胞扁平;头状腺毛和囊状腺毛分布于白鲜地上各器官,如茎、叶、花序轴、花萼、花瓣、花丝、子房;头状腺毛为多细胞分泌表皮毛,头部细胞由多数细胞组成,柄部由两列细胞组成;囊状腺毛兼有头状腺毛、分泌囊和非腺毛的结构特征,具有头状腺毛膨大的头部、非腺毛喙状的顶部以及膨大头部中分泌囊的结构。非腺毛分布与腺毛类似,但在花丝中尚未发现,其为单细胞的表皮毛。非腺毛、头状腺毛、囊状腺毛和分泌囊均起源于原表皮细胞;非腺毛、头状腺毛由原表皮直接发育而来。分泌囊和囊状腺毛则由原表皮细胞平周分裂后产生的内侧子细胞分别向内和向外发育形成,并且在发育过程中均出现细胞的降解,为溶生型分泌组织。头状腺毛、囊状腺毛和分泌囊是挥发油的重要积累位点。囊状腺毛发育过程中的细胞学特征表现为:中央细胞或鞘细胞核畸形、染色体边缘化或紧贴核膜、后期细胞核完全消失;质体膜出芽膨大被拧断到细胞质中、或膜系统最终紊乱;逐渐降解的线粒体和质体在发育后期被液泡吞噬;凝集的细胞壁逐渐膨胀,最终完全降解,呈现为细胞程序性死亡(PCD)特征。显微结构和DAPI染色显示:非腺毛、头状腺毛和分泌囊的发育过程中也显示了如膜系统紊乱、大量的内吞小泡、液泡中大量弥散的絮状物质、以及细胞核的逐渐消失等PCD的特征。白藓三类分泌组织和非腺毛均起源于原表皮,向外分化可形成非腺毛、头状腺毛,向内分化形成分泌囊,而囊状腺毛则是原表皮细胞向外分化而兼有分泌囊特征的腺体。它们在产生分泌物的同时伴随着胞程序性死亡(P CD),最终完成的它们的使命。更多还原

【Abstract】 Histochemistry, light, transmission and scanning electron microscopy were used in the present work to study the events during ontogeny of three types of glands and one type of nonglandular hair in Dictamnus dasycarpus. An intermediate type of secretory structure, namely trichome cavity, is determined, characterized by many respects in morphological complexity between non-glandular hair, capitate glandular hairs and secretory cavities. Non-glandular hairs, capitate glandular hairs, secretory cavities and trichome cavities are entirely initiated from protoepidermal cell. And the secretory cavities and trichome cavities develop from the lower daughter cell arising through a periclinal division of a protodermal cell. The secretory cavities and trichome cavities occur through lysis of the internal cells or including the sheath cells. The three types of glands are important sites for essential oil synthesis. Several morphological features of PCD in trichome cavities have been determined, such as misshapen nucleus by DAPI, condensed choromatins located closely to nuclear envelop, degenerated plastids and mitochondris engulfed by vacuoles, and lysis of swelled and twisted cell walls. The non-glandular hair, secretory cavity and capitate glandular hair are also indicating degenerated characters including degenerated membrane system, presence of numerous endocytic vacuoles and diffused flocculent material in the vacuole, and degenerated nucleus. Together these anatomical similarities support the hypothesis that the glands and non-glandular hair in Dictamnus dasycarpus are homologous in origin, and also share a similar ultimate fate, programmed cell death (PCD). Ultimately, an explaination on development and evolution of these glands and non-glandular hairs are also determined in this study.更多还原