Plant Physiology: Signals from Sunlight

A set of 50 fill-in-the-blank flashcards based on plant physiology focusing on sunlight signaling.

__ are responsible for absorbing light and initiating physiological responses in plants.

Photoreceptors

Phytochromes absorb light primarily in the __ and far-red regions of the spectrum.

red light (600-750 nm)

Seed germination requires __ light to initiate growth.

red

_ is the term for plants altering their growth patterns in response to light direction.

Phototropism

Plants use the __ to regulate their flowering in response to day length.

photoperiodism

Ultraviolet __ radiation can influence plant development and signaling.

UV-B

__ responses involve the bending of leaves toward sunlight.

Solar tracking

Phototropins mediate __ movements in plants in response to blue light.

chloroplast

_ responses are characterized by a rapid physiological change in response to light.

Immediate

___ responses occur over a longer duration, such as gene expression changes.

Long-term

The absorption spectrum of phytochrome is primarily associated with __ light.

red and far red

The __ form of phytochrome is physiologically active and promotes various developmental processes.

Pfr

Photomorphogenesis refers to the growth patterns resulting from __ exposure.

light

Blue light is detected by __, which play critical roles in regulating plant growth and development.

cryptochromes

Photoreceptors are proteins with a light-absorbing __ that absorb specific wavelengths of light.

chromophore

UVR8 is a specific photoreceptor that responds to __ light.

UV-B

The __ is an essential structure that absorbs blue light and regulates stomatal opening.

phototropin

Pfr phytochrome promotes __ formation, including anthocyanin production.

chlorophyll

Phototropism is mediated by __ receptors that respond to directional light.

blue light

Phytochromes interconvert between two forms based on light exposure: Pr and __.

Pfr

The phenomenon of __ involves seeds requiring light for germination.

photoblasty

__ light stimulates stomatal movements and affects photosynthesis in plants.

Blue

Phototropin induces __ opening by increasing turgor pressure in guard cells.

stomatal

The action spectrum of a biological response is compared to the __ spectrum of a photoreceptor.

absorption

Responses that require very low fluence levels are classified as __.

very low fluence responses (VLFRs)

Phototropins autophosphorylate in response to __ light, activating their signaling pathways.

blue

In the absence of light, cryptochromes inhibit __ degradation in plants.

protein

__ processes are rapid, occurring within seconds of light exposure, involving ion fluxes.

Immediate physiological

Photoreceptors initiate __ signaling pathways leading to specific responses in plants.

gene expression

Plants with compromised phototropins exhibit reduced __ efficiency.

photosynthetic

Phytochrome plays a role in regulating flowering through the __ of Pfr.

activation

BLUS1 is a protein that signals for __ opening in response to blue light.

stomatal

The phototropism of plants is linked to the action of the __ photoreceptors.

blue light

The __ action spectrum of phytochrome is matched to its absorption spectrum for seed germination.

photomorphogenic

UV-B light triggers the degradation of __ in plants, affecting gene regulation.

protein

Phototropism primarily utilizes __ for sensitivity to blue light.

phototropins

The phytochrome system interconverts Pfr and Pr, with the conversion referred to as __.

photoreversibility

The accumulation of __ is enhanced under red light through phytochrome signaling.

chlorophyll

The spatial distribution of __ within the cell is influenced by light exposure.

chloroplasts

Gene regulation in response to UV-B involves the interaction of UVR8 with __.

COP1-SPA complex

The response of leaves during solar tracking is primarily due to __ action.

photoreceptor

In Arabidopsis, continuous blue light promotes __, while red light can inhibit it.

flowering

__ is a measure of light responsiveness based on duration and intensity of exposure.

Fluence

Phytochrome interacting factors (PIFs) regulate gene expression by acting as __.

transcriptional regulators

The primary photoreceptor that responds to UV-B radiation is __.

UVR8

Phototropins are involved in the autophosphorylation process that modulates __ activity.

kinase

Plants adjust phototropic responses based on both blue and __ light signals.

red

The structural change in phytochrome due to light exposure affects __ conformation.

protein

The __ signaling pathway is crucial for UV-B induced responses in plants.

UVR8

Plants demonstrate differential responses to light wavelengths, resulting in __ adjustments.

developmental