肉桂维管组织发育的形态学研究OA

[Objective]This study aims to elucidate the morphological and structural changes of vascular tissues in C.cassia during development,as well as the deposition patterns of the major cell wall components,lignin and cellulose.[Method]Stem segments ranging from the shoot apex to the semi-lignified stage were collected as representative samples of key developmental stages.After paraffin embedding and sectioning,the samples were stained with safranin-O and fast green for histological observation.The morphological and structural changes during vascular tissue development were systematically analyzed using light microscopy.Lignin deposition was specifically detected by combining Wiesner reaction and autofluorescence methods,while cellulose was visualized and analyzed using calcofluor white staining.[Result]The development of vascular tissues in C.cassia begins with meristematic cells at the shoot apex,which gradually differentiate into procambium initial cells.These initial cells further develop into procambium cells and phloem fibers.Some procambium cells differentiate into primary phloem and primary xylem,while others gradually develop into the cambium,which subsequently differentiates into secondary phloem and secondary xylem.During secondary growth,active periclinal divisions were observed in phloem ray cells,suggesting their possible involvement in the formation of secondary phloem cells.As vascular tissues develop,phloem fiber cells undergo cell wall thickening and exhibit relatively high lignin and cellulose contents.Xylem consistently maintains a high lignin content,while cambium cells contain almost no lignin and have a lower cellulose content compared with xylem and phloem.[Conclusion]This study provides a clear depiction of the developmental trajectories of both primary and secondary vascular tissues in C.cassia,along with the dynamic changes and characteristics of lignin and cellulose deposition in the cell walls of these tissues.These findings lay a foundation for further investigation into the regulatory mechanisms underlying vascular tissue development in C.cassia and offer valuable insights for future studies on the quality formation mechanism of this medicinal plant.