野葛块根的异常结构解剖学研究

2015年版《中国药典》记载中药葛根来源于植物野葛Pueraria lobata的干燥根,该研究在对野葛根系的实地调查及对块根的解剖学研究基础上,阐明野葛膨大块根的发育与异常结构的关系。结果表明,野葛的根系有种子发育和不定根发育2种类型,根系中的根可根据形态和功能分为膨大的块根、不定根和输导根3种类型;块根由不定根发育而来,其次生结构符合双子叶植物根的次生结构特征;随着根的发育,块根的次生韧皮部外侧开始出现片段状的异常维管组织,最终根中的异常维管组织呈"同心环状"分布于次生维管组织的外方,膨大的块根可具有4~6个环状的异常维管组织;野葛块根的性状是其内部异常维管组织的发育形成的,异常维管组织的木质部和韧皮部是膨大块根的主体部分。研究结果揭示了野葛块根中异常结构的解剖,也为合理采收野葛药用部位、促进资源可持续利用提供了理论依据。

Microscopic anatomy of abnormal structure in root tuber of Pueraria lobata

Puerariae Lobatae Radix, also known as Gegen, is a root derived from Pueraria lobata. Based on field investigation and the developmental anatomy of root tuber, we have elucidated the relationship between the growth of root tuber and the anomalous structure. The results of analysis showed that the root system of P. lobata was developed from seed and adventitious root and there existed root tuber, adventitious root and conductive root according to morphology and function. The root tuber was developed from adventitious root, its secondary structure conformed to the secondary structure of dicotyledon's root. With the development of root, the secondary phloem of root tuber appeared abnormal vascular tissue, which was distributed like ring in the outside of secondary vascular tissue. The root tuber might have 4-6 concentric circular permutation abnormal vascular tissuelobate, and was formed by the internal development of abnormal vascular tissue. The xylem and phloem of abnormal vascular tissue were the main body of the root tuber. The results reveal the abnormal anatomical structure development of P. lobata, also provides the theoretical basis for reasonable harvest medicinal parts and promoting sustainable utilization of resources of P. lobata.