喜树各器官解剖学及其喜树碱含量测定的研究

运用植物解剖学方法研究了喜树各器官的结构,对喜树不同器官中喜树碱含量进行了HPLC法测定。结果表明:(1)喜树根尖纵切面的结构由根冠、分生区、伸长区和根毛区4个部分组成。根和茎的初生结构都由表皮、皮层和维管柱3部分组成;在根和茎初生结构的皮层和髓部具有被锇酸染成黑色的嗜锇细胞;在次生生长中,根的木栓形成层起源于中柱鞘,茎的木栓形成层起源于皮层细胞;随着次生维管组织的增加,茎的中央形成髓腔。(2)叶片由表皮、叶肉和叶脉组成,叶肉细胞中分布有嗜锇细胞;光学显微镜和扫描电子显微镜观察显示,喜树叶的上表皮没有气孔器分布;下表皮气孔器的保卫细胞呈肾形,没有副卫细胞,被几个表皮细胞不规则的围绕,属于无规则型;在上下表皮均分布着单细胞非腺毛和2种类型的腺毛,其中下表皮的分布相对稠密;上表皮腺毛呈球形,下表皮腺毛大部分为长卵形,其中间杂着一些球形腺毛;观察发现,越幼嫩的叶中,分布的腺毛和非腺毛越多。(3)喜树不同器官中喜树碱含量以幼叶和种子中较高,木质部中较低,髓中含量最少;随着叶的发育成熟,叶中喜树碱的含量逐渐降低,且同一叶的不同部位,喜树碱含量也有差异;喜树幼苗发育过程中喜树碱含量也在不断变化。

Structures of Organs and Determination of Camptothecin of Camptotheca acuminata Decne.

The structures of different organs of Camptotheca acuminata Decne.were studied using anatomical methods and the dynamic changes of CPT contents of different organs were identified by HPLC.The result indicated that:(1)The structure of root longitudinal section of C.acuminata is the same as other dicotyledons,namely,it is composed of root cap,meristematic zone,elongation zone and maturation zone.The primary structures of root and stem are composed of epidermis,cortex and vascular cylinder.Osmiophilic cells are showed in cortexs and piths.In secondary growth,the cork cambium of root derives from pericycle,while the cork cambium of stem derives from cortex.With the secondary growth,the center of stem becomes hollow.The cross section of blade is composed of epidermis,mesophyll and vein,and osmiophilic cells are also found in the mesophyll.With scanning electron microscope and optics microscope observing,stomatal apparatus are only absent in adaxial epidermis of leaf and abnormity.The guard cells are nephroid,and subsidiary cells have not been observed.The leaf surface has three types of trichomes,one type is unicellular non-glandular which is distributed in the adaxial and abaxial epidermis of leaf.Other types are glandular hairs,in which one is global distributed in both adaxial and abaxial epidermis and the other is olivary distributed only in the abaxial epidermis.It was found that the younger the leaf is,the more the trichomes are distributed.(3)The HLPC results showed CPT contents in young leaf and seed is higher than that in xylem,the lowest in piths.CPT content of leaf gradually decreased with the leaf becoming mature.The content has differences between different parts in the same leaf.CPT contents have changed in the development of C.acuminata seedling.