Question

Describe various modification of root and stem and their significance​

Answer 1

Answer:

1) Root

Distinguish the root features:

The root is the part of the plant that typically emerges from the embryo’s radicle.

It renders rigidity against water and wind and firmly fixes the plant to the ground.

Absorption of minerals and water from the soil.

It is positively geotropic, it grows towards the centre of the gravity.

It has unicellular root hairs.

Normally, it grows away from light. It is negatively phototropic.

It does not yield leaves, buds and flowers that do not have internodes and nodes.

Answer 2

★ Roots :

→ Roots are non-green structures which grow under the ground.

★ Modifications of roots :

• Store food : The food prepared by the leaves is stored in the roots plants. For example, Carrot, sweet potato, and turnip roots of these plants.

• Roots give extra support to the plants.

• For nutrition : Some plants grow in nutrient, - deficit regions. They have specialised roots and parasitic roots arising from their stem which helps them to absorb water and nutrients from the host.

• Roots of plants such as Dahlia can develop into new plants.

★ Significance of roots :

• Roots anchor the plant firmly into the soil.

• Roots help to prevent soil erosion by binding the soil particles.

• Roots absorb water, minerals and other nutrients from the soil which are mandatory for the growth of a plant.

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★ Stem :

→ Stem is the long and main axis of the plant body.

★ Modifications of stems :

• For support : Stems gives support to the plant. Plants like gourd, grapevine and passion flower have weak stems.

• To manufacture food : Some stems are modified to make food. Cactus grows in Deserts. The leaves of cactus plants are reduced into spines so as to prevent the loss of water from the surface of the leaves.

• For storage of food : Stems of some plants are modified to store food. For example, potato onion and Ginger are underground stems which are modified to store food.

• For storage of water : Stems of some plants like cactus swell up to store water in them.

• For protection : Some stems are modified to provide protection. Stems of some plants like lemon have thorns. Grazing animals don't prefer eating them. Hence, they provide protection to the plants.

• For multiplication of the plants : Stems like bulbs and tubers help in increasing the number of plants. Stem cutting of some plants such as Jasmine and Rose grow into new plants.

★ Significance of stems :

• The stems helps the plant to stand upright.

• Stems bears leaves, flowers, branches and fruits. The arrangement of leaves is this manner, so that they will receive maximum sunlight.

• The stem transports water, minerals and food.