Question

Explain the phases of growth in the meristem of plants.

Answer 1

Hint: The plants are also made up of different types of tissues similar to animals. The basic tissue in plants, which give rise to all types of other tissues, is called meristematic tissue. When it is differentiated, it gives rise to different types of permanent tissues.

Complete answer: The meristematic tissues are present at the tip of shoot and roots. These tissues help in the elongation of shoot and root as well as they also increase the girth of the shoot and root by cell division.
Thee meristematic tissue may be of three types
-Apical meristem- it is present at the tip of the root or shoots. It is actively dividing tissue and it increases the length
of the plant.
-Intercalary meristem: it is found near the nodes and it increases the size of the internodes between two nodes.
-Lateral meristem: it is present in the lateral side of the stem and roots and it increases the girth of the stem and root. The growth of the meristem has three phases and the tissues are divided into three zones like zone of cell division,the zone of cell elongation and zone of cell differentiation.
Cell division phase: in this phage, the cells divide actively at the tip of the root and shoot and produce a large undifferentiated mass of cells filled with plenty of cytoplasm surrounded by a thin cell wall.
Cell elongation phase: In this phage, the cells present next to the zone meristematic cells increase their size by the creation of a vacuole in the cytoplasm and they also increase their size.
Cell maturation phase: it takes place in the zone present next to the zone of elongation. The cells in this zone gain their maximum size and their cell wall becomes thick due to the deposition of chemicals like lignin, pectin.

Note: The different phages of the development of meristematic tissues produce permanent tissue like parenchymatous,collenchymatous and sclerenchymatous tissue. These tissues make different complex tissues in a plant like a vascular bundle, xylem and phloem that help in the transport of water with dissolved minerals and food from leaves to other parts of the plant.