Plants take up nutrients form soil, water and air. They absorb various nutrients and water present in the soil through the roots while oxygen is taken up through leaves.

Plants acquire nutrients through various processes, including absorption, photosynthesis, and symbiotic relationships with other organisms. Let's explore each of these mechanisms in detail:

Absorption:
Plants have roots that serve as their primary organs for nutrient absorption. The root system consists of tiny root hairs that significantly increase the surface area for nutrient uptake. Key steps involved in nutrient absorption are:

1. Root Hair Development: Root hairs are extensions of epidermal cells on the surface of roots. They are responsible for increasing the surface area of the root, facilitating better nutrient absorption.

2. Osmosis: Nutrients present in the soil, such as water, minerals, and ions, move through soil particles and enter the root zone. The process of osmosis allows water and dissolved nutrients to pass through the semipermeable cell membrane of root hairs.

3. Active Transport: Some nutrients are present in low concentrations in the soil. To acquire these essential elements, plants use active transport mechanisms. This process requires energy and involves the movement of ions against their concentration gradient.

Photosynthesis:
Photosynthesis is a vital process through which plants produce their own food using sunlight, water, and carbon dioxide. While plants primarily rely on absorption for nutrient uptake, they also manufacture some nutrients through photosynthesis. Key points related to photosynthesis are:

1. Chlorophyll: Chlorophyll, a pigment found in chloroplasts, captures sunlight energy and initiates the process of photosynthesis.

2. Carbon Dioxide: Carbon dioxide is obtained from the atmosphere through tiny pores called stomata present on the leaves. It enters the plant and is used in the synthesis of glucose.

3. Water: Water is absorbed by the roots and transported to the leaves through specialized tissues called xylem. It provides the necessary hydrogen and oxygen required for photosynthesis.

4. Glucose Production: During photosynthesis, plants convert carbon dioxide and water into glucose. Glucose serves as the primary energy source for all cellular activities and aids in the production of other essential nutrients.

Symbiotic Relationships:
Plants establish symbiotic relationships with various organisms to acquire nutrients. Two common examples are:

1. Mycorrhizal Association: Mycorrhizal fungi form a mutually beneficial relationship with plant roots. They extend their hyphae into the soil, increasing the root surface area and enhancing nutrient absorption. In return, the fungi receive sugars and other organic compounds from the plants.

2. Nitrogen Fixation: Certain bacteria, such as Rhizobium, form nodules on the roots of leguminous plants. These bacteria convert atmospheric nitrogen into a form that plants can utilize. In return, plants provide the bacteria with carbohydrates.

In summary, plants obtain nutrients through absorption from the soil via their root system, photosynthesis using sunlight, water, and carbon dioxide, and symbiotic relationships with beneficial organisms. These processes ensure the plants' nutritional needs are met for growth, development, and reproduction.