Test: Plant Hormones - SSC CGL MCQ

Auxin primarily functions to stimulate stem and root elongation in plants. This hormone is responsible for promoting cell elongation in the stem and roots, leading to the overall growth of the plant. Additionally, auxin plays a crucial role in various other processes such as apical dominance, parthenocarpy, and rooting for stem cuttings.

Auxin triggers parthenocarpy in plants, which is the development of fruit without fertilization. This process is facilitated by auxin's ability to stimulate fruit development even in the absence of pollination. Parthenocarpy is a valuable trait in certain crops as it ensures fruit production without the need for pollination, enhancing crop yield in specific circumstances.

Auxin is the plant hormone responsible for inducing apical dominance in plants. This process involves the suppression of lateral bud growth by auxin produced in the apical bud. By inhibiting the growth of lateral buds, auxin redirects the plant's resources towards the growth of the main, or apical, bud, leading to vertical growth and the development of a dominant main stem.

Auxin aids in the process of rooting for stem cuttings by stimulating root development. When applied to stem cuttings, auxin encourages the formation of roots at the base of the cutting, enabling it to establish itself as a new plant. This rooting hormone helps initiate and promote the growth of roots, facilitating the successful propagation of plants through cuttings.

2,4-D (2,4-Dichlorophenoxyacetic acid) is a synthetic auxin that is widely used as a herbicide in agriculture. It selectively targets and eliminates dicot weeds without affecting monocots, making it a valuable tool for weed control in various crop systems. The herbicidal properties of 2,4-D are attributed to its ability to disrupt the growth processes in dicot plants, leading to their eventual death while sparing monocot plants.

Gibberellins play a crucial role in promoting stem elongation in plants. This function is particularly important in reversing dwarfism and encouraging rapid growth in various plant species.

Cytokinins are responsible for promoting lateral and adventitious shoot growth in plants. This function is essential for plant tissue culture and the initiation of new cultures from plant parts.

Abscisic Acid is known for promoting leaf senescence in plants. This hormone plays a role in the aging and shedding of leaves, contributing to the overall growth and development cycle of the plant.

Gibberellins are responsible for promoting bolting in rosette plants like cabbage and beet. This sudden elongation of internodes before flowering is a key developmental process facilitated by this hormone.

Cytokinins play a crucial role in mobilizing nutrients within plants and delaying leaf senescence. This function aids in maintaining plant health and vitality by ensuring efficient nutrient utilization and prolonging leaf longevity.

Ethylene plays a crucial role in accelerating fruit ripening. This function is significant in the agricultural industry where the controlled ripening of fruits is essential for timely harvest and distribution. Ethylene triggers the production of enzymes that break down cell walls, converting starches to sugars, and causing the fruit to ripen. It is important for farmers and distributors to understand ethylene's role in fruit ripening to manage produce effectively.

Ethylene promotes the aging and shedding of leaves and flowers in plants. This process is essential for the plant's growth and development cycle, as shedding older leaves and flowers allows the plant to redirect nutrients and energy to new growth areas. Understanding this function of ethylene can help horticulturists and gardeners manage plant growth and health effectively.

Ethylene does not inhibit the formation of the apical hook in dicot seedlings. Instead, it actually promotes this process. The apical hook protects the delicate shoot apex as it pushes through the soil during germination. Understanding how ethylene influences plant morphology is critical for botanists and researchers studying plant development.

Ethylene plays a crucial role in inducing root growth and root hair formation in plants. This hormone increases the absorption surface of roots, allowing plants to efficiently uptake nutrients and water from the soil. Understanding the mechanisms by which ethylene influences root development is vital for agronomists and plant biologists working to improve crop yields and plant health.

Ethylene's promotion of the formation of the apical hook in dicot seedlings is crucial for protecting the delicate shoot apex during germination. The apical hook allows the shoot to penetrate the soil efficiently and protects it from damage. Understanding this process can help botanists and researchers appreciate the intricate mechanisms plants have evolved to ensure successful growth and survival.