Development and plasticity

Development covers all the changes an organism goes through in its life cycle, from seed germination to senescence.

The sequence in a plant cell (also true of tissues and organs): a meristematic cell divides, grows (plasmatic growth), expands by elongation, differentiates and matures into a mature cell, which finally undergoes senescence and death.

Plasticity is the ability of plants to follow different pathways, in response to the environment or to phases of life, and so form different kinds of structures.

Heterophylly linked to phase of life: in cotton, coriander and larkspur the leaves of the juvenile plant differ in shape from those of the mature plant.

Heterophylly caused by the environment: buttercup makes differently shaped leaves in air and in water.

Development, the sum of growth and differentiation, is controlled by intrinsic factors (intracellular genetic factors and intercellular chemicals such as plant growth regulators) and extrinsic factors (light, temperature, water, oxygen, nutrition and so on).