Development of unisexual flowers.

Cells destined to form male or female parts are selectively deleted. The example shown is maize.

Pollen and egg cell production.

Also post-meiotic development of the micro- and mega-sporophye. The picture is of day-lily.

Embryo differentiation.

Degeneration of suspensor cells.

Cereal grain development.

Development of starchy endosperm in cereal grain maturation and senescence of aleurone cells during germination (the structure of the wheat grain is shown).

Cork etc.

Formation of xylem, sclerenchyma, bark and other specialized cell types such as epidermal hairs, oil glands, and abscission layers.

Generation of complex organ forms.

For example, death of strips of cells (called lorae) resulting in the fan-like shape of palm leaves.

Senescence of organs.

Including leaves, roots, flower parts and the tissues of ripening fruits. The illustration shows tepal senescence in Alstroemeria, from the research group of Hilary Rogers in University of Cardiff.

Reactions to abiotic stress.

The examples are of aerenchyma formation under anaerobic conditions: (a)cross-section of a maize root; (b) Phragmites. From: SHFW Justin, W Armstrong (1987) New Phytologist 106: 465-495.

Responses to biotic stresses.

The picture shows the hypersensitive response of tobacco, in which pathogen infection triggers defensive cell death in the host.