Roots are the underground extension of plants that are used to give them a base and firm support. Roots provide mechanical support to the stem and upper plant body. The characteristics of roots are discussed below in detail:

• Roots are cylindrical structures that grow from the radicle of the seed embryo.
• They are homogenous and are not differentiated into internodes and nodes as the leaves.
• They absorb water from the soil along with the nutrients.
• They also help in conducting the waste materials back into the soil.

• Food storage: In carrots and turnips, the edible parts are found in the roots.
• Support: The extension of roots supports huge trees, such as banyan, in the form of vertically hanging roots.
• Osmosis: Osmosis is the absorption of water from the soil by the roots due to the pressure difference.
• Absorption: Roots absorb the nutrients from the soil.
• Imbibition: It is a process by which the dead cells of the roots absorb the nearby water molecules into the roots.

Mineral nutrition: There are different concepts related to plant roots that help us understand how plants absorb water and nutrients from the soil. Macro- and micro-nutrients are found in the soil and are absorbed by the roots and transferred to the plant leaves.

It is a process by which green plants use sunlight and other absorbed water and nutrients to synthesise their food necessary for their survival. A green pigment called chlorophyll is the site for synthesising food, which releases oxygen as its by-product. Every green plant goes through this process as it is used in the food synthesis process, which is necessary for plant growth and development.

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

According to the above equation, carbon dioxide and water molecules combine in the presence of sunlight to form glucose and release oxygen.

Transport phenomenon takes place continuously inside plants. For example, the food is synthesised in the leaves, but the apical stem needs that food to move upwards. Similarly, the roots are the parts that are in direct contact with the raw nutrients and water that is required to synthesise food. For the same purpose, plants have special vascular bundles that are used to transport different items up and down the plant’s body. There are two types of vascular bundles present inside the plants—unidirectional and multidirectional. The xylem vessels are unidirectional, and they transport the water and nutrients from the roots to the upper side of the plant body. The phloem vessels are multidirectional vascular bundles that transfer the food and nutrients to any part of the body as required.

Plant Respiration: Plants use the leaves for breathing and making food. The plants that synthesise their own food are called autotrophs. The stomata are tiny pores present on the lower side of the leaves. They help the plant in respiration. Stomata are present on the epidermis section of the leaves and are visible under the light microscope. They are also found on the stem and other different parts of the plant.

Plant physiology comprises various processes and phenomena that help a plant grow. These processes include photosynthesis, transportation and respiration, essential for a plant’s survival and growth on earth.

1. What are the different parts of a plant?
   The different plant parts include the roots, leaves, stem, flower, buds etc.
2. Explain the process of respiration in plants.
   Plants make energy from respiration, which is used to drive the various physiological processes inside the plants. There are stomata on the lower side of the leaves from which the plant respiration takes place. Carbon dioxide is used in the synthesis of food for the plants, and oxygen is released out.
3. What are the two transportation vessels inside plants?
   Plants have two vascular bundles known as the xylem and phloem. These are used to transport the water and nutrients inside the plant body.
4. Discuss the plant growth and development process briefly.
   The plant growth starts from the germination stage, which continues as the plant grows from the seed and grows throughout its life in terms of height and width.
5. What are some functions of plants?
   The plants give us food, retain the soil, bring rain and provide us with oxygen.