Anomalous Secondary Growth
Any deviation from the normal type of secondary growth is called anomalous secondary growth. It is common in plants of tropical regions for example:
- Secondary growth in monocots like Dracaena , Agave, Yucca, Aloe by accessory cambia.
- Growth in palms is by the activity of primary thickening of apical meristem and persistent leaf bases.
- Formation of phloem pockets in the xylem region by the abnormal behaviour of normal cambium in Bignonia, a lianas(woody climber), also called Pyrostegia.
- Cambium forms vascular tissues only in the region of vascular bundles.
Significance of Secondary Growth
- Secondary growth adds to the girth of the plant. It provides support to increase the weight of the aerial growth.
- Secondary growth produces a corky bark around the tree trunk that protects the interior from abrasion, heat, cold and infection.
- It adds new conducting tissues for replacing old non-functioning ones as well as for meeting increased demand for long distant transport of sap and organic nutrients.
Secondary Growth
Term tissue ( French word meaning woven ) was used by N.Grew (1682) the father of plant anatomy. Nageli is regarded as the father of Modern Anatomy. A cell is the functional and structural unit of life. A tissue is a group of cells having a common origin, the same method of development, and function. Anatomy deals with the internal organization of plants. In plants, the terms anatomy and histology have the same meaning. Different organs in plants show differences in their internal structure. Within angiosperms, the monocots and dicots are also seen to be anatomically different. The internal structures show adaptations to diverse environments.