Problem 128 - Objective Biology for NEET

Question

Auxin \(2,4-\mathrm{D}\) is used for what? (a) To remove weeds from farms by formers (b) To remove weeds from lawn by gardeners (c) To induce flowering in horticulture (d) All of these

Step-by-Step Solution

Answer

The correct answer is (d) All of these.

Step 1: Understand the nature of the compound

Auxin \(2,4-\mathrm{D}\) is a type of synthetic auxin, which is an important plant hormone. It's often used in both agricultural and horticultural settings due to its ability to regulate the growth of plants.

Step 2: Consider the scenarios

Each scenario presents a different situation where Auxin \(2,4-\mathrm{D}\) might be used. The compound can be used to remove undesirable plants such as weeds from both farms and lawns. Moreover, it has a crucial role in prompting flowering in horticulture.

Step 3: Conclude the answer

Given its aforementioned applications in various settings, it can be concluded that Auxin \(2,4-\mathrm{D}\) may be used for all of these purposes.

Key Concepts

2,4-D

2,4-D, short for 2,4-dichlorophenoxyacetic acid, is a widely used herbicide and plant growth regulator. It mimics the natural plant hormone auxin, which is crucial in regulating plant growth and development. This synthetic auxin is particularly effective in targeting broadleaf weeds, making it a popular choice in agriculture and horticulture. By imitating the plant's natural growth hormones, 2,4-D disrupts the normal growth patterns of weeds.

• This disruption leads to uncontrolled growth that ultimately kills the weed.
• It is selective, which means it primarily affects dicot plants (broadleaf weeds) rather than monocot plants (grasses and cereals).

Understanding 2,4-D helps us see why it's an essential tool for farmers and gardeners alike.

Plant Hormone

Plant hormones, also known as phytohormones, are natural substances that regulate various aspects of plant growth and development. Auxins, like 2,4-D, are one of the several main classes of plant hormones. They play a significant role in cell elongation, root formation, and differentiation of xylem and phloem. Unlike synthetic auxins, natural auxins occur specifically within the plant to help it respond to light, gravity, and touch.

• Auxins facilitate the plant's directional growth, known as tropisms, which include phototropism and geotropism.
• They are also involved in the elongation of stems and the suppression of lateral bud growth.

Plant hormones are a key driver in a plant's ability to adapt and thrive in its environment.

Weed Control

Weed control is an essential aspect of both agriculture and horticulture, as weeds can significantly reduce the yield of crops and damage the appearance of lawns and gardens. 2,4-D is commonly used as a herbicide to manage weeds due to its effectiveness on broadleaf plant species. Effective weed control is crucial for several reasons:

• Weeds compete with desired crops for nutrients, water, and sunlight.
• They can act as hosts for pests and diseases that may affect crops.
• Proper weed management can improve crop quality and yield.

By using herbicides like 2,4-D, farmers and gardeners can maintain healthier plant environments and better achieve their agricultural goals.

Horticulture

Horticulture involves the science and art of cultivating plants such as fruits, vegetables, flowers, and ornamental plants. The use of 2,4-D in horticulture is primarily centered on its ability to control undesirable plants and encourage the growth of desired species. Additionally, auxins can play a role in rooting of cuttings and flowering induction.

• Using synthetic auxins can help propagate plants more effectively by stimulating root growth.
• They can also be used to manage growth patterns of ornamental plants.

Horticulturists often utilize 2,4-D to ensure the health and aesthetic quality of their gardens and landscapes.

Flower Induction

Flower induction refers to the process of triggering flower development in plants, which is an important aspect of both agriculture and horticulture. The synthetic auxin 2,4-D, alongside other plant hormones, can be used to stimulate flowering under certain conditions.

• This can help synchronize flowering times, which is important for harvesting and maximizing yield.
• Synthetic auxins can also potentially enhance flowering in certain horticultural settings.

By understanding and manipulating the plant hormone pathways, growers can effectively induce flowering, ensuring that plants bloom at the most beneficial times for cultivation and harvest.