Huntington>Conservatory>Plant Lab>Stems

Stem


The two main functions of a stem are structural support and nutrient conduction. It needs to support and elevate leaves for maximal light reception. It needs to transfer water, minerals and nutrients between the roots and leaves. Stems can also function as food storage organs.

Stems and leaves are structurally and developmentally very closely related. They are parts of the plant section called "shoot" (plant's upper portion), in contrast with root. The new growth of a stem is also called a shoot.

Illustration of a shoot
Meristem: a group of active dividing, undifferentiated cells found in the growth region (shoot or root) of a plant.
Apical (terminal) Meristem: meristem at the tip of a shoot or root. New cells generated by the apical meristem are responsible for the elongation of shoots and roots (Primary Growth).
Lateral Meristem: meristem that are responsible for the widening of shoots and roots (Secondary Growth). Example: vascular cambium.
Apical (terminal) bud: the uncovered apical meristem of the stem. In order to space out leaves and branches, a growing terminal bud inhibits the development of lateral buds: this is called apical dominance.
Axillary bud: a dormant bud of meristematic tissue, inhibited by the apical meristem. If the inhibition is removed or grows far enough away, the axillary bud may develop into a shoot, a flowering branch, or other strucure.

Morphologically, stems can be divided into two regions:
Node: stem region with the buds that can give rise to leaves.
Internode: stem region between two adjacent nodes. It contains lenticels, which are small pores that connect to internal tissues and allow gas exchange.


Back to Plant Lab mainpage

Back to Conservatory


Copyright for the photos on this website belongs to Pu Chen. Images should not be redistributed without the permission of the photographer.