What is Stem?
The stem is the ascending part of the axis that bears branches, leaves, fruits, buds, and flowers. Together, this system is known as the shoot system.
The stem develops from the plumule of the embryo of a germinating seed. The region of the stem where a leaf arises is called a node and the region between two nodes is called an internode. The stem is generally green and tender when the plants are young, and becomes brown and woody once they grow as trees.
The function of the stem: The stem conducts water, minerals, and photosynthates from the roots to different parts of the plants. Few stems may also perform storage of food, support, protection, and vegetative propagation in plants.
Modifications of stem: Stems are modified to perform various functions.
1. Storage of food (E.g. potato plant, ginger, and turmeric plant)
2. Act as organs of perennation to tide over conditions of unfavorable growth
3. Stem tendrils developed from axillary buds, help plants to climb to the adjacent strong surface (E.G cucumber plant, watermelon)
4. Axillary buds of stems are modified into thorns to protect plants from grazing animals (Rose plant)
5. In desert regions, the stems are modified into flattened (Opuntia) or fleshy cylindrical structures (Euphorbias), which are useful in performing photosynthesis.
6. Underground stems spread to new niches and form new plants, thus spreading and propagating the plant (E.g grass)
7. In some plants, a slender lateral branch arises from the base of the main axis and grows downwards to touch the ground, thus providing support to the plant (E.g Jasmine plant)
A. Storage
B. Support
C. protection
D. spread and vegetative propagation
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