Lecture 11

Plant Adaptations

Features that enhance a plant's survival in a specific environment.

Succulent Leaves

Thick, fleshy leaves that store water, useful in arid climates.

Constitutive Defenses

Defensive traits that are always present in a plant, including physical and chemical barriers to herbivores and pathogens.

Trichomes

Hair-like structures on plant surfaces that can deter herbivores by being sharp or sticky.

Laticifers

Specialized cells in plants that produce latex, which can gum up the mouths of herbivores.

Ant-Plant Symbiosis

A mutualistic relationship where ants live in plants and protect them in exchange for food.

Secondary Metabolites

Chemicals produced by plants that can deter herbivores or pathogens but are not essential for primary functions.

Induced Responses

Plant responses that are activated by environmental stimuli, unlike constitutive defenses.

Auxin

A plant hormone that regulates growth, directionality of growth, and responses to light and gravity.

Phototropism

Growth movement of a plant toward light, promoted by auxin.

Gravitropism

Growth response of a plant to gravity, with positive gravitropism being downward growth.

Apical Dominance

The phenomenon where the main central stem grows more strongly than secondary stems.

Ethylene Gas

A plant hormone that regulates leaf abscission and fruit ripening, causing a positive feedback in ripening.

Apical Hook

A growth structure that prevents elongation at the surface allowing inner surfaces to grow.