Stem is a part of plant which lies above from surface of soil i.e. it shows negative geotropic growth. It has nodes and internodes. Branches, leaf, flower bud and bracts are developed from nodes. Stem arises from plumule.
Characteristics of a Stem
- It develops from the plumule of the embryo.
- The stem is the aerial part of the plant and it possesses leaves, fruits, branches, and flowers.
- The stem is positively phototropic and negatively geotropic.
- The leaves contain chlorophyll so that plants can make food.
- The stem possesses nodes and internodes.
- The young stem is green.
- The stem also consists of a terminal and axillary buds.
Forms of a Stem
- Caudex: It is unbranched, erect, cylindrical stout stem and marked with scars of fallen leaves. Crown of leaves are present at the top of plant. eg.: Palm
- Culm: Stem is jointed with solid nodes & hollow internodes. eg. Bamboo (Graminae)
- Excurrent: The branches arise from the main stem in acropetal succession and the tree assumes a cone like appearance e.g. Pinus, Eucalyptus, Casuarina, etc.
- Decurrent (Deliquescent): The lateral branches grow more vigorously and outcompetes the main trunk, giving a dome-shaped appearance, e.g., mango (Mangifera indica), shishem (Dalbergia sissoo) and banyan (Ficus bengalensis).
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By Team Learning Mantras