C3.1 Phytohormones HL Only | Quizlet

Auxin

a plant hormone that causes the elongation of cells in shoots and is involved in regulating plant growth.

Meristem

a region of plant tissue, at the growing tips of roots and shoots, consisting of actively dividing cells that can differentiate to form new tissues.

Apical dominance

phenomenon in which the closer a bud is to the stem's apex, the more its growth is inhibited

Tropism

A growth response of a plant toward or away from a stimulus

Phototropism

Growth of a plant shoot or root toward or away from light.

positive phototropism

growth of a shoot toward light

auxin efflux pumps

specialised membrane proteins that use ATP to move auxins laterally out of cells located closer to the light

Proton pumps

membrane proteins that use ATP to move protons from the interior of the cell to the exterior / cell wall

Cytokinins

Plant hormones that stimulate cell division and cytokinesis

Ethylene

plant hormone that stimulates fruits to ripen

Fruit Ripening​

changes in fruit that make it softer, sweeter and change its colour

positive feedback

A type of regulation that responds to a change in conditions by initiating responses that will amplify (increase) the initial change. Takes organism away from a steady state.

auxin : cytokinin

Ratio of two phytohormones that regulates shoot & root growth