Plant Hormones Flashcards

Flashcards about plant hormones based on lecture notes.

What is a plant hormone?

A chemical signal for intercellular regulation and coordination of metabolism, growth, and morphogenesis.

Name the five classical plant hormones.

Auxins, Cytokinins, Ethylene, Abscisic Acid, Gibberellins

What is the most common natural auxin?

IAA (indoleacetic acid)

Name two tropic responses affected by auxins.

Phototropism and Gravitropism

Which hormone inhibits the growth of lateral buds, leading to apical dominance?

Auxin

What are some commercial applications of auxins?

Rooting hormone and plant tissue culture.

Give examples of Cytokinins.

Kinetin and Zeatin

What are some effects of Cytokinins?

Promotion of shoot formation in tissue culture and delay of leaf senescence.

What are some commercial applications of Cytokinins?

Plant tissue culture and delay of senescence in cut flowers.

What are some effects of Ethylene?

Fruit ripening, leaf and flower senescence, and leaf and fruit abscission.

What is a commercial application of Ethylene?

Fruit loosening for mechanical harvest.

What are some effects of Abscisic Acid (ABA)?

Stomatal closure, embryo and seed development, and dormancy in seeds and buds

What stresses induce Abscisic Acid (ABA) production?

Drought, salt stress, and freezing.

What are some effects of Gibberellins (GA)?

Hyperelongation of shoots, stimulation of flowering, enlarged fruits, and induction of seed germination.

What are some commercial applications of Gibberellins (GA)?

Parthenocarpic fruit production and uniform seed germination for barley malt production.

Where are the sites of Auxin biosynthesis?

Leaf primordia, young leaves, and developing seeds.

Where are the sites of Cytokinin biosynthesis?

Primarily in root tips.

Where are the sites of Abscisic Acid biosynthesis?

Mature leaves, roots (especially under water stress), and seeds.

What is involved in signal transduction?

Hormone receptor, second messengers.

What is the purpose of signal transduction?

Convert the signal into a physiological response and amplify the signal.