| A | B |
|---|
| abiotic | Nonliving |
| abscisic acid (ABA) | slows down growth often antagonizing actions of growth hormones |
| action potential | change in the membrane potential of an excitable cell |
| action spectrum | graph that depicts the effectiveness of different wavelengths of radiation in driving a process |
| apoptosis | changes that occur within a cell as it undergoes programmed cell death |
| auxin | plant hormone that has a variety of effects (cell elongation root formation secondary growth fruit growth) |
| avirulent | pathogen that can only mildly harm but not kill the host plant. |
| biotic | all the organisms that are part of the environment |
| blue-light photoreceptors | light receptors initiate a variety of responses (phototropism and slowing of hypocotyl elongation) |
| brassinosteroids | plant steroid hormones that cause cell elongation retard leaf abscission and promoting xylem differentiation |
| circadian rhythm | cycle of about 24 hours that persists even in the absence of external cues |
| cytokinins | that retard aging and act in concert with auxin to stimulate cell division |
| day-neutral plant | plant whose flowering is not affected by photoperiod |
| de-etiolation | changes a plant shoot undergoes in response to sunlight |
| elicitor | molecule that induces a broad type of host defense response |
| ethylene | gaseous plant hormone response to mechanical stress programmed cell death leaf abscission and fruit ripeningmorphological adaptations for growing in darkness |
| etiolation | enzymes that break the cross-links |
| expansins | enzymes that break the cross-links between cellulose microfibrils and other cell wall constituents |
| florigen | flowering signal may be a hormone or may be a change in relative concentrations of multiple hormones |
| gene-for-gene recognition | disease resistance involving recognition of pathogen-derived molecules by the protein products |
| gibberellins | hormones that stimulate growth in the stem and leaves trigger the germination of seeds and breaking of bud dormancy |
| gravitropism | response of a plant or animal to gravity |
| heat-shock protein | protect other proteins during heat stress |
| hormone | chemical signals that are formed in specialized cells travel in body fluids and act on specific target cells |
| hypersensitive response (HR) | localized defense response to a pathogen |
| jasmonic acid | molecule in plant defense against herbivores |
| long-day plant | flowers only when the light period is longer than a critical length |
| oligosaccharin | elicitor derived from cellulose fragments released by cell wall damage |
| photomorphogenesis | Effects of light on plant morphology |
| photoperiodism | physiological response to photoperiod the relative lengths of night and day |
| phototropism | Growth of a plant shoot toward or away from light |
| phytoalexin | plant antibiotic that destroys microorganisms or inhibits their growth |
| phytochromes | light receptors absorbing red light that regulate many plant responses (seed germination & shade avoidance) |
| PR protein | protein involved in plant responses to pathogens |
| salicylic acid | hormone that may be partially responsible for activating systemic acquired resistance to pathogens |
| second messenger | relays a signal to a cell’s interior in response to a signal received by a signal receptor protein |
| short-day plant | flowers only when the light period is shorter than a critical length |
| statolith | specialized plastid that contains dense starch grains and may play a role in detecting gravity |
| systemic acquired resistance (SAR) | defensive response in infected plants that helps protect healthy tissue from pathogenic invasion |
| thigmomorphogenesis | response in plants to chronic mechanical stimulation |
| thigmotropism | directional growth of a plant in response to touch |
| triple response | growth maneuver in response to mechanical stress (slows stem elongation thickens stem horizontal growth) |
| tropism | growth response that results in the curvature of whole plant organs toward or away from stimuli |
| vernalization | use of cold treatment to induce a plant to flower |
| virulent | term describing a pathogen against which a plant has little specific defense |
