Question

Write a note on the patterns of branching in stem and their significance.

Answer 1

Stem is the aerial part of a plant. It develops from the plumule. Branches are the structural members of the stem system, but not a part of the trunk or the central axis of a plant or tree. Branches are present in different patterns in plants.

Complete step by step answer: The structural members of the stem system are known as branches. They are found in different shapes and sizes. Branches can be horizontal, diagonal and vertical.
Branching patterns are primarily of two types. They are discussed below:
Dichotomous branching
In dichotomous branching, the branches develop typically from the apical buds. The buds divide into two branches. Dichotomous branching is again of two types –
Monopodial branching – the condition when the central axis continues to grow. Beech trees demonstrate a monopodial branching system.
Sympodial branching – when the terminal buds stops growth. Joshua trees demonstrate sympodial branching system.
Lateral Branching
Branching pattern that arises from the axillary buds is known as Lateral Branch system. Lateral branching may be of two types:
Racemose type – when the apical bud grows indefinitely, axillary buds grow on the branch in an acropetal manner. The branches that arise from these axillary buds form the racemose branch system. Conifers exhibit racemose branching.
Cymose type – when the apical bud does not develop, the branches are only formed from axillary buds forming the cymose branch system. Cymose branching can be of three types. They are Uniparous cymose when one branch develops at each branching, Biparous if two branches develop at each branching or Multiparous if more than two branches develop at each branching point. Uniparous branching can be seen in Ashoka tree, Biparous and Multiparous branching can be seen in Carissa and Red Oleander, respectively.
Patterns of branching are of great importance to a plant. The branching pattern determines the shape of the plant, spatial distribution of leaves in the canopy, thereby determining the amount of light absorbed. Branching patterns are known to help the plant form its inflorescence.

Note: Branching patterns of plants can be of different kinds. Branches determine plant shape, and regulates light absorption. Branches generally develop from either axillary buds or apical buds. Branching patterns are important in horticulture and agriculture. Removal of axillary buds can produce better crops of certain plants like tomatoes.