Studies On The Structures Of Venetum In Three Kinds Of Circumstance

In order to elucidate the structure which roots,stems and leaves of three kinds of venetum in different enviroment. We used of paraffin slice and light microscopy to study.It was found that quantity of fiber cells are very more than others,diameter of cells are big ,wall of the cell were thick, secretory cavity were small.The cell fiber changing xylem,are also especial much.and metaphloem are also especial good.Three kinds of Venetum of roots contrast with each other in different enviroment.It indicates:the roots of them evolute obvious different structure,following ecological environment transform.In the sandy soil(1),vascular cylinder protoxylem are triarch;In saline-alkali soil(2) vascular cylinder protoxylem are tetrarch;In the black soil(3) vascular cylinder protoxylem are diarch.According regular evolution of the plant structure ,woody plant are original;herbaceous plant are evolution.Experiment indicate that in the black soil its structure are more evolution than the others.Three kinds of Venetum of stems contrast with each other in different enviroment.It indicate:in the cross section ,cortex parenchyma cell contain mass cell ergastic substance.All phloems are bicollateral bundle.This kink of bicollaterlal bundle just increase one multiple transport with mutrition than ordinary bundle.In the phloem laticifer disperse distribution likely ring,meanwhile,in the pith also disperse laticifer and secretory canal.These secretory structure and parenchyma cell relate with containing kinds of composite for medicinal purposes closely.