Question

Why are root nodules useful for plants?

Answer 1

Hint: The plants have different parts that involve different functions for their development. The leaves are involved in the photosynthesis process, the stems are involved in the transportation and conduction of water, food, and nutrients to every part of the plant body, and the roots are involved in providing support and absorbs nutrients from the soil for the growth of the plant.

Complete step by step answer:
To solve this question, we should know about the roots. The roots are mostly the first structure to form from a seed. It involves the absorption of minerals and water from the soil for transportation to the other parts of plants. The structure of root is composed of root cap that has parenchyma cells for the protection of root tissue during its growth.
The root cap has many layers like epidermal layer, then cortex, it is made of ground tissues, it is found between the epidermis and vascular tissue of the root. The inner boundary of the cortex is the endodermis; this is a part of the cell wall and consists of a waterproof strip termed a casparian strip. The next layer of root cap is pericycle found next to the epidermis towards the center of the root, this tissue involved in the formation of lateral root. The function of the root cap is to protect the delicate stem cells inside the root tip and transmit and receive the environmental signals to the growing root because of this function the root cap is found in the very tip of the root.
Now, the root nodules are found in the leguminous plants. The nitrogen fixing bacteria lik Rhizobium are found inside the nodules. This Rhizobium can utilise the atmospheric nitrogen directly and converts it into nitrogenous compounds like nitrates and ammonia. The ammonia and nitrates are involved in the plant growth, therefore the root nodules are useful for the plants and the nitrogen fixing bacteria as well, they show mutualism relation.

Note:
Root hairs are formed from epidermal cells that are found in roots, this involved in the increasing the surface area of roots. The function of the root hairs is, it involves in the uptake of nutrients and water from the rhizosphere.