What is Plant Stems?

A stem supports leaves and flowers and helps transport materials between roots and upper plant parts. Herbaceous and woody stems have different features.

Stem structure and transport

Stems have nodes where leaves attach and internodes between them. Terminal and lateral buds may develop into shoots, leaves, or flowers. Xylem in vascular bundles carries water and minerals; phloem distributes photosynthetic products. This transport is not a simple one-way flow: source and sink regions can change with season and development. Some stems become storage organs, as in potato tubers; rhizomes grow horizontally underground, and climbing stems may attach to supports. Stem form affects access to light and response to environmental conditions.

Herbaceous stems, wood, and growth

Herbaceous stems are often soft and green; woody stems thicken through secondary growth. In some plants, dividing tissue called cambium produces new vascular tissues. Annual-ring patterns in trees can reflect growth conditions, but rings do not form identically in every species. Strength depends on cell-wall structure, branching, and the environment as well as the amount of wood. Pruning, injury, and water stress can alter development. A stem is not only a thick upright trunk: the organ includes many forms, from slender climbing shoots to underground storage structures.