Chapter 14: Phytohormone Gibberellins

These flashcards cover key concepts and functions of gibberellins, as presented in Chapter 14.

Gibberellins (GA)

A group of tetracyclic diterpenoid acids that are important plant hormones involved in various growth processes.

Internode elongation

The elongation of the sections between plant nodes, significantly promoted by gibberellins, particularly in dwarf seedlings.

GA3

Also known as gibberellic acid, it is the most abundant gibberellin produced by the fungus F. fujikuroi and is commonly used in agriculture.

Dwarf seedlings

Seedlings that exhibit reduced growth due to a lack of biologically active gibberellins like GA1, leading to internal deficiencies.

Photomorphogenesis

The growth and development of plants in response to light; gibberellins enhance hypocotyl cell elongation during this process.

DELLA proteins

Repressor proteins that inhibit the action of gibberellins and regulate growth and development in plants.

Seed germination

The process whereby a seed begins to grow, which is regulated by gibberellins through the induction of α-amylase.

Bolting

The rapid elongation of the stem in rosette plants, induced by gibberellins, allowing plants to flower.

Regulation of gibberellins

Involves feedback loops, where gibberellin levels influence their own biosynthesis and catabolism.

GA1

A biologically active gibberellin that controls stem elongation; its precursor GA20 is converted by the enzyme GA3 oxidase.