The stem

The stem Julia GuillenTete AguilarGaby Rivas

Moo Raymundo

The Stem

• A stem is one of two main structural axes of a vascular plant.

Stems (gaby )• In most plants stems are located

above the soil surface but some plants have underground stems

• A stem develops buds and shoots and usually grows above the ground. Inside the stem, materials move up and down the tissues of the transport system.

• The term shoots is often confused with stems; shoots generally refer to new fresh plant growth and does include stems but also to other structures like leaves or flowers

Parts of the Stem (juls)• The stem is normally divided into nodes and

internodes.• Main stem: the most important one in the plant• Secondary stem: grow from the main stem• The nodes: hold buds which grow into one or

more leaves, flowers, cones or other stems etc. • The internodes: distance one node from another. • Buds: are the responsible for plant growth;

either new stems, flowers or leaves.• - parts of the buds• Main terminal bud: is in charged of the upwards

growing of the plant• Secondary terminal bud: come out from the tip

of secondary stems, they make the secondary stem grow

• Lateral buds: are placed on the stem nodes, leaves and flowers arise from it

Functions (moo)• Stems have four main functions which are:

• Support for and the elevation of leaves, flowers and fruits. The stems keep the leaves in the light and provide a place for the plant to keep its flowers and fruits.

• Transport of fluids between the roots and the shoots in the xylem and phloem.

• Storage of nutrients. • The production of new living tissue. The

normal life span of plant cells is one to three years. Stems have cells called meristems that annually generate new living tissue.

• xylem is one of the two types of transport tissue, phloem being the other

Types of stems (tete)Herbaceus stems• Annual plants: plant with a year life-time.

Weeds generally belong to this group.• Vivacious plants: plants with aerial stems

lasting a single season, but keeping underground structures from wich new stems spring again next season.

Ligneous stems• Trees: in this case we call the stems

trunks.• Shrubs: they grow from one to five meters

tall and their branching begins at soil level• Bushes: they grow shorter than one meter

tall.