Biology Plant and Animal behaviour

Physical factors in the environment such as temperature, light intensity and humidity

Plant growth substance that acts as a powerful growth inhibitor and plays an important part in maintaining dormancy in seeds and winter buds and may also be involved in gravitropism in roots

The breaking of leaves, fruits and flowers as a result of the formation of a layer of weakness at the base.

Graph of the proportion of light absorbed by a pigment plotted against a wavelength

Stem cells derived from adult tissue (including umbilical cord)

Nerve fibre that conveys impulses from a receptor to the central nervous system

inhibition of the grpwth of competing species of plants by the production of growth-inhibiting substances by a plant

starch-storing organelle, probably involved in gravitropism