Plant Hormones and Growth Responses

30 vocabulary flashcards related to plant hormones and their role in growth responses.

Plant Hormones

Chemicals that enable plant cells to communicate and facilitate responses to stimuli.

Signal Transduction

The process by which a molecular signal binds to a receptor and initiates a cellular response.

Auxins

Plant hormones that promote root and fruit growth and prevent the growth of axillary buds.

Gibberellins

Growth-promoting hormones that cause stem elongation; most common form is gibberellic acid.

Cytokinins

Hormones that promote cell division and prolong the life of flower cuttings and stored vegetables.

Abscisic Acid (ABA)

A growth inhibitor and 'stress' hormone that initiates and maintains seed and bud dormancy.

Ethylene

A gaseous hormone that stimulates the dropping of leaves, fruits, and flowers, as well as fruit ripening.

Gravitropism

Growth response of plants to gravity; roots grow downward and stems grow upward.

Phototropism

Growth response of plants to light; stems grow toward light due to auxin concentration.

Thigmotropism

Growth response of plants to touch, such as coiling tendrils around supports.

Nastic Movements

Movements in plants that do not involve growth and are not dependent on the direction of the stimulus.

Turgor Pressure

Pressure exerted by fluid in plant cells that maintains cell structure and drives cell elongation.

Circadian Rhythms

Biological processes that follow a roughly 24-hour cycle, influenced by light and dark.

Photoperiodism

Plant's response to the length of day and night, influencing flowering and growth.

Phytochrome

A blue-green pigment in plants that detects changes in light wavelengths related to photoperiodism.

Apical Dominance

Inhibition of axillary bud growth by auxins produced in the shoot apical meristem.

Statoliths

Gravity sensors in plants that aid in gravitropic responses by detecting gravitational changes.

Abscission

The process of dropping leaves, fruits, or flowers, often stimulated by ethylene.

Thigmomorphogenesis

Growth response of an entire plant to stimuli such as wind or rain.

Wound Response

Plant defense mechanisms activated in response to physical injury, including proteinase inhibitors.

Mutualistic Relationships

Interactions between plants and animals that benefit both, e.g., acacia trees and acacia ants.

Auxin Concentration

The gradient of auxins that causes differential growth in response to directional light.

Senescence

The aging process in plants that can be delayed by the interaction of auxins and cytokinins.

Dormancy

A state of inactivity in seeds and buds maintained by abscisic acid in response to stress.

Leaf Drop Mechanism

The action of ethylene stimulating enzymes that lead to the dropping of leaves and fruits.

Tannins

Secondary metabolites that serve as a chemical defense in plants against herbivores.

Alkaloids

Bitter-tasting compounds that serve as defenses against herbivory.

Cyanogenic Glycosides

Compounds that release cyanide when the plant is damaged, deterring herbivores.

Proteinase Inhibitors

Proteins produced in response to wounds that inhibit the digestive enzymes of herbivores.

Systemin

A signaling molecule released in response to wounding that triggers defensive responses.

Hormonal Controls

The regulation of plant growth and development through various plant hormones.

Auxin Receptors

Membrane proteins that bind auxins and initiate the plant's growth responses.

Proton Pump Activation

The mechanism by which auxins induce cell elongation by lowering cell wall pH.

Seed Germination

The process initiated by phytochrome signaling as plants detect changes in light exposure.