Plant Responses to Internal and External Signals

These flashcards cover vocabulary and definitions related to plant responses to internal and external signals, including hormonal functions, signal transduction, and physiological adaptations.

Stimulus

An environmental factor that elicits a response in plants or animals.

Responses

The actions or changes in behavior resulting from a stimulus.

Etiolation

Morphological adaptations for growing in darkness, characterized by pale stems and unexpanded leaves.

De-etiolation

The process of a plant undergoing changes when exposed to light.

Signal transduction pathways

Processes that link signal reception to the resulting response in cells.

Receptor

A cellular protein that detects specific environmental stimuli.

Post-translational modification

A process that activates preexisting enzymes.

Transcriptional regulation

A mechanism that increases or decreases the synthesis of mRNA for specific enzymes.

Cytokinins

Plant hormones that promote cell division and are produced in actively growing tissues.

Auxins

Plant hormones that stimulate cell elongation, root initiation, and fruit development.

Gibberellins

Hormones that promote stem elongation and influence fruit growth and seed germination.

Abscisic Acid (ABA)

A hormone that inhibits growth, promotes seed dormancy, and signals drought response.

Ethylene

A gas that regulates fruit ripening, leaf abscission, and programmed cell death.

Second messengers

Molecules that transfer and amplify signals from receptors during signal transduction.

Transduction

The conversion of one kind of signal or stimulus into another within a cell.

Phytochrome

A plant photoreceptor that detects red and far-red light.

Germination

The process by which a seed develops into a new plant.

Apical dominance

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

Phototropism

A plant's growth response to light direction.

Gravitropism

A plant's growth response to gravity.

Senescence

The process of aging in plants, leading to the eventual death of some tissues.

Leaf abscission

The process by which leaves are shed from a plant.

Cell differentiation

The process in which cells develop into distinct types with specific functions.

Stomata

Small openings on the surfaces of leaves that control gas exchange.

Hormone

A signaling molecule that induces specific responses in target cells at low concentrations.

Cell signaling

The process through which cells communicate and respond to their environment.

Transcription factor

Proteins that bind to DNA and control the transcription of specific genes.

Ca2+ channels

Protein channels that allow calcium ions to enter the cell, playing a role in signal transduction.

Cyclic GMP (cGMP)

A second messenger involved in various signaling pathways in plants.

Transport mechanisms

The means by which hormones move within plants, including phloem and xylem.

Water stress

A condition in which water availability is limited, affecting plant physiological processes.

Developmental stage

The current phase of growth and development of a plant.

Endodermis

The innermost layer of cells in the root that regulates the flow of water and nutrients.

Phloem

Vascular tissue responsible for transporting sugars and hormones throughout the plant.

Xylem

Vascular tissue responsible for transporting water and minerals from the roots to other parts.

Meristem

Undifferentiated plant tissue capable of continuous growth and development.

Apical meristem

Growing tips of roots and shoots where new cells are produced.

Root meristem

Region at the tip of the root that produces new root cells.

Secondary growth

Growth in thickness of plants, often involving the cambium.

Chlorophyll production

The synthesis of chlorophyll, essential for photosynthesis in plants.

Cell wall

A rigid outer layer surrounding plant cells, providing structural support.

Cytoplasm

The material within a cell, excluding the nucleus, where various metabolic processes occur.

Plasma membrane

The semipermeable membrane surrounding the cytoplasm of a cell.

Photosynthesis

The process by which plants convert light energy into chemical energy.

Juvenility

The early growth stage of a plant before it becomes mature and reproductive.

Hormonal balance

The appropriate levels of different hormones that regulate plant growth and development.

Accelerated growth

Increased growth rates typically in response to environmental stimuli.

Stem thickening

The process of stem strengthening often in response to mechanical stress.

Root initiation

The process by which new roots are formed from stem cuttings or tissues.

Fruit ripening

The developmental process that leads to the maturation and edible state of fruits.

Chemical signaling

The transmission of signals between cells through chemical substances.

Environmental cues

External signals such as light, temperature, and moisture that affect plant behavior.

Mobile signaling molecules

Hormones that can move through the plant to elicit a response.

Target cells

Cells that are specifically affected by a signaling molecule.

Response diversity

The range of different responses that can result from the same stimulus.

Biosynthesis

The process by which living organisms produce complex compounds from simpler ones.

Specificity of action

The unique response triggered by a hormone at a particular site.

Plant growth regulators

Substances that influence plant growth and development in various ways.

Dual pathways

Two different signaling routes that can lead to the same biological outcome.

Immediate response

A rapid change in cellular activity occurring right after a stimulus.

Long-term effects

The enduring impact of hormones on plant growth and development.

Viability of seeds

The potential for seeds to germinate and develop into healthy plants.

Drought response

Adaptive changes in plants to cope with water scarcity.

Plant physiology

The study of the internal functions and processes of plants.

Apoptosis

Programmed cell death that helps in shaping the plant structure.

Resistive adaptations

Features that help plants withstand environmental stresses.

Seasonal effects

Changes in plant behavior and growth depending on the season.

Tissue differentiation

The process in which cells become specialized for specific functions.

Stress signals

Indications that a plant is undergoing stress from environmental factors.

Tropic response

Growth responses of plants towards or away from stimuli.

Plant anatomy

The study of the structural features of plants.

Root hair formation

The development of small hair-like structures on roots to increase surface area for absorption.

Translocation

The movement of nutrients and water through a plant's vascular system.

Flowering signals

Environmental cues that trigger the transition to flowering in plants.

Vascular tissues

The specialized tissues in a plant responsible for the transport of water and nutrients.