| A | B |
|---|
| phototropism | growth of plant shoots towards light |
| Darwin Auxin Experiments | ldetermined chemical signal for phototropism made in shoot tip |
| Boysen-Jensen Auxin Experiments | verified chemical signal production in tip diffuses to shoot |
| hormone | chemical agent produced in one part of body activates an effect in a different part of body |
| auxin | any substance that promotes seedling elongation |
| cytokinins | growth regulators that promote cell division |
| gibberellins | plant growth regulator stimulates both cell division and elongation |
| abscisic acid (ABA) | contributes to seed dormancy |
| ethylene | gas that trigers fruit ripening and cell death |
| tropisms | plant growth toward /away from a stimulus |
| positive tropism | plant growth towards a stimulus |
| negative tropism | plant growth away from a stimulus |
| gravitropism | plant growth in relation to gravity |
| chemotropism | plant growth in relation to a chemical |
| thigmotropism | plant growth in relation to touch |
| circadian rhythm | innate 24 hour biological cycle |
| biological clocks | internal timekeeprs of organisms that regulate circadian rhythms |
| photoperiod | environment stimulus detects relative lengths of night/day |
| short-day plant | plants that flower when night periods are longer |
| long-day plant | plants that flower when night periods are shorter |
| phytochromes | light absorbing (sensing) proteins in plants |
| Pr phytochrome | red absorbing phytochrome |
| Pfr phytochrome | far red absorbing phytochrome |
| herbivory | plant defenses against plant eating animals |
| systemic acquired resistance | plant defenses against pathogens |
