Atlas of plant and animal histology

Home / Images / Plan: Primary stem,dicot, anise

Virtual microscopy


Image: primary stem of a dicot plant, anise, stained with safranin / Alcian blue.

Epidermis: it is the outermost cell layer of the stem. In this case, the epidermis consist of cells not showing a thick cuticle. Stoma can be observed in the epidermis.

Collenchyma: it is the tissue found below the epidermis at the same radial position than the vascular bundles. The collenchyma cells show thickenings in their cell walls with mechanical support function. In this case, it is an angular collenchyma.

Photosynthesizing parenchyma: it is a thin discontinuous layer of parenchyma cells containing chloroplasts. It is located just below the epidermis.

Cortical parenchyma: it is the parenchyma tissue between the photosynthesizing parenchyma/angular parenchyma and the vascular bundles. The cortical parenchyma is formed of large cells with cell walls stained in blue.

Primary phloem: it is the vascular tissue specialized in transporting organic molecules. The primary phloem is situated toward the superficial region of the stem. It consists of small cells with thin cell walls stained in blue. Secretory canals can be observed among the phloem cells.

Procambium: it is the meristem found in the vascular bundles, located between the primary phloem and the primary xylem. By proliferation and differentiation, the procambium produce primary phloem outward and primary xylem inward.

Primary xylem: it is the vascular tissue specialized in transporting water and minerals. The primary xylem is made up of large conducting cells with red cell walls, small cells with thick cell walls (sclerenchyma fibers) and small parenchyma cells with thin blue cell walls.

Secretory canals: they are glandular ducts made up of parenchyma secretory cell. These secretory canals can be observed between the vascular bundles and the angular collenchyma, and in the primary phloem.

Pith: it is the deeper tissue, below the vascular bundles. The pith is made up of large parenchymatic cells with cell walls stained in blue. It can be observed that the central part of the pith is empty because parenchyma is degenerated.