伏毛铁棒锤根系异常次生生长及生物碱组化定位

目的]明确宁夏六盘山伏毛铁棒锤根系结构、生长方式及生物碱在组织中的分布。方法]采用石蜡切片及生物碱定位技术。结果]伏毛铁棒锤根系由主根、侧根和不定根（块根）组成。根系初生结构正常,次生结构异常。主根的形成层和额外形成层产生了异常次生结构中的＂U＂形次生维管束和三生维管束,且主根的筛管群是由初生韧皮部和形成层分化的小筛管群组成。而块根的次生木质部呈＂U＂形,次生韧皮薄壁细胞占据了块根的绝大部分,且块根的筛管群主要由次生韧皮薄壁细胞分化形成。结论]主根和块根的形成层组成及活动方式的不同导致了二者异常次生结构的不同。生物碱在主根中主要积累于内侧皮层和束间薄壁细胞,在块根中主要在次生韧皮薄壁细胞和髓中。

Abnormal Secondary Growth and Histochemical Localization of Alkaloids in Root System of Aconitum flavum Hand.-Mazz.

Objective] The purpose of this study was to clarify the structure,growth pattern and histochemical localization of alkaloids in root system of Aconitum flavum Hand.-Mazz.Method] Paraffin sectioning and histochemistry were employed for performing the analysis in this study.Result] The root system of Aconitum flavum Hand.-Mazz.consists of taproot,lateral root and adventitious root.The primary structure of root system is normal,but secondary structure shows abnormal.The cambium and the extra cambium of taproot form a "U"-shaped secondary vascular bundle and tertiary bundle in abnormal secondary structure.The sieve tube group is made of little sieve tube group which is differentiated from primary phloem and cambium.Meanwhile,the secondary xylem in tuberous root also appears to be a "U" shape.Parenchyma cells of secondary phloem occupy most of the tuberous root.The sieve tube group of tuberous root is mainly differentiated from parenchyma cell of secondary phloem.Conclusion] The difference in abnormal secondary structure of taproot and tuberous root are attributed to their varied cambium compose and activity pattern.Alkaloids are mainly accumulated in parenchyma cell of the inside cortex and between bundle in taproot,while parenchyma of secondary phloem and pith in tuberous root.