Question

Plant growth in length is increased by
A)Apical meristem
B)Lateral meristem
C)Dermatogen
D)Periblem

Answer 1

In plant growth is restricted to certain part and it is known as meristems.Meristems are of different types Apical meristems,lateral meristems and intercalary meristems

Complete answer:
Before analyzing the options let us know a little more about plant growth.Plant growth is the increase of plant volume or increase in size by cell enlargement and cell reproduction. In this cell growth increases the size of cells and cell reproduction results in an increased number of cells. Most of the plants continue their growth through their entire lifetime. All cells in the plant cannot be divided and those which cannot be divided are called permanent cells. The dividing cells of plants are known as meristematic cells.meristematic cells are seen as the growing part of plants that are in root ,shoot, nodes etc. It is the type of plant tissue which consists of undifferentiated cells that will continue division and differentiation. Based on their position the meristems are classified into apical meristems,lateral meristem and intercalary meristem.

Option A)Apical meristems are seen at the apex of root and shoot in both monocot and dicot plants.They are actively dividing cells and produces growth hormone Auxin that helps in the lengthwise growth of all plants.So this is the correct option
Option B)Lateral meristems that are seen only in dicot plants that help in increase in girth of plants that is secondary growth.So it does not help in the lengthwise growth of plants. So this is an incorrect option
Option C )Dermatogen is also a meristematic tissue and it is the part of apical meristem and it forms the outermost layer of plant that is epidermis.So this is an incorrect option
Option D)Periblem it is also a part of apical meristem and hypodermis,cortex,and endodermis are formed from this. So this is an incorrect option

Hence, the correct answer is option ()

Note: In dicot plant both apical meristems and lateral meristems are seen.so dicot plant increase in length and girth.Monocot plant contain apical meristem and intercalary meristem .(intercalary meristems intercalated between nodes and help to increase the node length) so monocot plants grow lengthwise and their thickness is less.