Stem is a long and large stalk which is the main body that serves as the support to vegetative and reproductive shoots. In addition, it is where the leaves grow and the primary root is connected. Moreover, the stem is part of shoot system of a plant.
Parts of the stem:
Apical bud - also known as terminal bud which is located at the tip of the plant where the shoot growth occurs.
Leaf - is a thin, flattened and usually green organ where the photosynthesis happens.
Petiole - the stalk that joins a leaf to a stem.
Node - is a point of attachment of a leaf.
Internode - a space between two nodes.
Axillary bud - a bud that grows at the axil of the leaf and is capable of developing into a branch shoot or flower cluster.
Characteristics of stems:
Stem develops from pumule and epicotyl of the embryo and it grows ascendingly and aerially of the plant axis.
Stem is generally negatively geotropic which grows upward and positively phototropic which grows downward.
Stem consist of terminal bud where shoot growth occurs, nodes where the leaf is attached to and grows, and internodes which is the space between two nodes.
Young stem is green and performs photosynthesis.
When stem is matured, flowers and fruits starts to develop on it.
Functions of stems:
Provides support to the plant and bear leaves, buds, flowers, and fruits.
Serves as a transportation of water and other minerals from roots to the rest of the parts of a plant.
Some of the stems conduct photosynthesis and stores water such as cactus.
The stem allows the leaves to arrange in a way that they are able to receive direct sunlight in order to efficiently perform photosynthesis and allow gas exchange.
Some stems are modified to carry out vegetative propagation which is a form of asexual reproduction seen in plants.
Forms of stems:
Aerial Stem - is a stem that grows vertically above the ground.
Erect Stem - is a stem that can stand upright without any support and grows above the ground.
Weak Stem - is a thin, soft, and weak stem that can't stand upright and therefore needs support. There are four types of weak stem namely climbers, twiner, trailers, and creepers.
Reduced Stem - is a stem that is being extremely reduced in bulbs.
Underground Modified Stem - is a stem that is being modified to for storage of food and it grows underground.