绿萝营养器官解剖结构
时间:2019-09-17 20:11 来源:毕业论文 作者:毕业论文 点击:次
| 摘 要：采用石蜡切片，在光学显微镜下观察绿萝（Epipremnum aureum）根、茎、叶的解剖结构。结果表明：根由表皮、周皮、皮层和文管柱组成。根表皮由单层细胞组成；周皮不明显；皮层约占横切面半径的3/4；文管柱初生木质部脊数为多原型, 后生木质部导管孔口较大。茎由表皮、皮层和文管柱组成。茎表皮为复表皮；皮层较厚，含少量散生文管束；文管柱无髓部。茎靠近表皮皮层多层细胞、皮层散生文管束四周、文管柱内都分布有叶绿体。叶柄由表皮、基本组织、文管束组成。叶柄表皮为复表皮；基本组织内分布有散生文管束；文管束四周分布有叶绿体。叶片有栅栏组织和海绵组织的分化；仅下表皮分布有平列型气孔器，上表皮细胞明显比下表皮大。绿萝茎和叶柄表皮为复表皮,叶片上表皮细胞较大,仅下表皮分布气孔器，这些特征可能与抗旱性有关。茎外表皮附近的皮层细胞、散生文管束四周、文管柱内都分布有叶绿体，与绿萝耐阴性有关。茎皮层中分布少量散生文管束，是比较少见的特征。 39142 毕业论文关键词：绿萝；营养器官；解剖结构；抗旱性；耐阴性 Study on Anatomical Structures of Vegetative Organs of Epipremnum aureum Abstract: This paper discussed the anatomical structures of vegetative organs, which includes roots and stems and leaves of Epipremnum aureum，with the light microscope by using paraffin method.The results were as follows. The roots of Epipremnum aureum was composed of epidermis, periderm, cortex and vascular cylinder. The epidermis was composed of monolayer cells. Periderm was not obvious. Cortex accounted for about 3/4 of the transverse section radius. The number of primary xylem ridge in vascular cylinder was polyarch. Metaxylem catheter orifice was larger. Stem was composed of epidermis, cortex and vascular cylinder.Epidermis of stems epidermis was multi-epidermis. Cortex was thick and contained a small amount of scattered vascular bundles.There were no pith in vascular cylinder.There were chloroplast in the multilayer cells close to the epidermal layer,around the atactostele in cortex and in the vascular cylinder. The petiole was composed of epidermis,ground tissue and vascular bundle. The epidermis of petiole epidermis was multi-epidermis.There were scattered vascular bundles in ground tissue and there were chloroplast around the vascular bundles.There were differentiation of palisade tissue and spongy tissue in leaves.There were paracytic type stomatal apparatus just in the epidermis.The upper epidermis cells were obvious larger than the lower epidermis.These characteristics may be related to drought resistance that stems and petioles were multi-epidermis,the upper epidermis cells were large,there were paracytic type stomatal apparatus just in the epidermis.The following characteristic may be associated with the shade tolerance:there were chloroplast in the multilayer cells close to the epidermal layer,around the atactostele in cortex and in the vascular cylinder.It was very rare that cortex of stems contained a small amount of scattered vascular bundles. Key words: Epipremnum aureum; Vegetative organs; Anatomical structure; Drought resistance;Shade tolerance 目录 引言 1 1 材料与方法 2 1.1供试材料 2 1.2实验方法 2 2 结果与分析 2 2.1根 3 2.2茎 3 2.3叶 3 3 讨论 致谢 8 参考文献 8 引言 绿萝（Epipremnum aureum）又名黄金葛,是天南星科(Araceae)的常绿藤本植物，喜湿热环境，喜富含腐殖质的微酸性土壤，阴性植物，忌阳光直射 [1]。绿萝叶片翠绿，气根发达，缠绕性强，生命力顽强，遇水即活，是比较大众化的优良室内盆栽。绿萝有许多种类，本实验采用的是青叶绿萝，与其他种类相比，青叶绿萝最显著的特征是叶子全部为青绿色，没有花纹和杂色，便于实验观察。 (责任编辑：qin) |