9.3 Growth in Plants

Meristems

tissues in a plant consisting of undifferentiated cells capable of indeterminate growth

Meristematic Tissue - Function

can allow plants to regrow structures or even form entirely new plants

Apical Meristems

occur at shoot and root tips and are responsible for primary growth - plant lengthening

Lateral Meristems

occur at the cambium and are responsible for secondary growth - plant thickening

Auxin

a group of hormones produced by the tip of a shoot or root that influences cell growth rate by changing the pattern of gene expression with a plant’s cells

Auxin Efflux Pumps

set up concentration gradients within tissues thereby changing the distribution of auxin within the plant

Function of Auxin in Shoots

stimulates cell elongation and thus high concentrations of auxin promote growth

Function of Auxin in Roots

Auxin inhibits cell elongation and this high concentrations of auxin limit growth

Tropisms

describe the growth or turning movement of an plant in response to a directional external stimulus

Phototropism

growth movement in response to a unidirectional light source

Gravitropism

a growth movement in response to gravitational forces

Micropopagation

a technique used to produce large numbers of identical plants from a selected stock plant

Mesocosms

enclosed environments that allow a small part of a natural environment to be observed under controlled conditions

Indoleacetic Acid

class of plant growth hormone (growth regulating factor)