Ch 36 Plant Behavior Terms Flashcards
Circadian Rhythm
(Latin—about day) Based on the influence of Earth’s rotation from day to night, plants, animals, and other organisms have evolved internal biological clocks. Ex. Include leaf movements, flower opening, fragrance emission.
Hormone
Chemical messengers that are within plants that interact with each other and exernal stimuli in an effort to maintain homeostasis.
Tropism
use phototropism as an example
A growth response that depends on a stimulus that occurs in a particular direction. Ie. Phototropism, the plant sense the direction of light and responds by changing the location of a plant hormone called auxin. The auxin influences gene expression and makes the stem bend toward the light.
Receptor
And where do they occur?
(AKA sensors) proteins that become activated when they receive a specific type of signal. Can occur anywhere, defense receptors in the plasma membrane, light r. in the cytosol, and auxin r in the nucleus.
Second Messenger
common types?
What does touch do?
Transmit messages from many types of activated receptors. Common are Cyclic AMP (cAMP), inositol triphosphate (IP3) and calcium ion (Ca2+)—most common. Touch can cause Ca2+ to flow from ER to cytosol. Ca2+ then alters the proteins to make them react to the stimulus.
Effector
What’s another name for them?
What happens once they do their job?
Molecules that directly influence cellular responses. Calcium-Dependent Proetin Kinases (CDPKs). Secondary messengers trip the effectors which trigger the cellular response. Cell signaling ends when an effector causes a cellular response.
Auxin Influx Carrier
AUX1 Proteins on the plasma membrane that transport negatively charged auxin (IAA-) into the cell.
Auxin Efflux Carrier
Why are they necessary?
Special proteins called PIN proteins transports auxin out of cells. Its charged nature does not easily diffuse out of a cell.
Polar Transport
AUX1 occurs at the apical ends of shoots and PIN proteins occur at the basal end. Therefore, auxin flows downward from shoots to roots.
Photoperiodism
A plant’s ability to measure and respond to light amounts and the length of the day is based on light receptors in cells.
Phototropin
Blue-light sensor involved in plant phototropism. The blue-light sensor—flavin—absorbs blue light and attaches to a kinase protein. Thus once the blue-light occurs, phototropin phosphorylates to trigger auxin movement.
Cryptochrome
In seedlings, they determine if the light environment is bright enough to allow photosynthesis. If not, seedlings continue to elongate through the soil toward light.
Phytochrome
Red-light receptor. It absorbs either red light or far-red light. Seeds use this to determine if they are close enough to the surface to germinate.
Aerenchyma
What plants already have this and what plants acquire it when needed?
To reduce the effects of flooding, a tissue containing large, snorkel-like air channels allow more oxygen to flow from shoots to the submerged roots. Plants are preprogramed in wetlands, and dry lands (corn) it is a response to flooding.
R Genes (Resistance genes)
plant disease receptor proteins. They recognize a pathogen or an elicitor’s presence and respond to resist the pathogen.
