Which of the following is the only gaseous plant growth regulator

Ethylene is a simple gaseous plant growth regulator (PGR). It is synthesised in large amounts bytissues undergoing senescence and ripening fruits. Influences of ethyleneon plants include horizontal growth of seedlings, swelling of the axis andapical hook formation in dicot seedlings. Ethylene promotes senescenceand abscission of plant organs especially of leaves and flowers. Ethyleneis highly effective in fruit ripening. It enhances the respiration rate duringripening of the fruits. This rise in rate of respiration is called as respiratory climactic.

Hormones are produced naturally by plants, while plant growth regulators are applied to plants by humans. Plant hormones and growth regulators are chemicals that affect: • Flowering. • Aging. • Root growth. • Distortion and killing of organs. • Prevention or promotion of stem elongation. • Color enhancement of fruit. • Prevention of leafing, leaf fall or both. • Many other conditions. Very small concentrations of these substances produce major growth changes. Compound Effect/Use Gibberellic acid (GA) Stimulates cell division and elongation, breaks dormancy, speeds germination Ethylene gas (CH 2) Ripening agent; stimulates leaf and fruit abscission Indoleacetic acid (IAA) Stimulates apical dominance, rooting, and leaf abscission Indolebutyric acid (IBA) Stimulates root growth Naphthalene acetic acid (NAA) Stimulates root growth, slows respiration (used as a dip on holly) Growth retardants (Alar, B-9, Cycocel, Arest) Prevent stem elongation in selected crops (e.g., chrysanthemums, poinsettias, and lilies) Herbicides (2,4-D, etc.) Distorts plant growth; selective and nonselective materials used for killing unwanted plants Plant growth regulators may be synthetic compounds, such as IBA and Cycocel, that mimic naturally occurring plant hormones, or they may be natural hormones that were extracted from plant tissue, such as IAA. These growth-regulating substances most often are applied as a spray to foliage or as a liquid drench to the soil around a plant's base. Applied concent...

Ethylene is recognized as a major gaseous plant growth regulator because it inhibits shoot elongation and favors caliper development, and along with auxin inhibits lateral bud development. One of its most pronounced physiological effects is abscission or the shedding of a plant part. Ethylene is a very simple plant hormone. So, both the statements are true but the reason is not the correct explanation for assertion.

Ethylene is a gaseous plant hormone that act as growth regulator. It inhibits plant growth. It is also called as ripening hormone. It is responsible for ripening of fruits. Fruit ripening is accompanied by increased rate of respiration. Ethylene in gaseous form is used to accelerate the process of ripening of fruits.

Which of the following growth regulators is an adenine derivative ? 1. Auxin 2. Cytokinin 3. Ethylene 4. Abscisic acid Past Year (2019 onward - NTA Papers) MCQs Plant Growth and Development Botany (2022) NEET Practice Questions, MCQs, Past Year Questions (PYQs), NCERT Questions, Question Bank, Class 11 and Class 12 Questions, and PDF solved with answers