Chapter 33. Control Systems In Plants Already Passed

thigmotropism {Ans: A directional growth of a plant in response to touch.}long-day plants {Ans: plants that bloom only when the period of day is longer than a specific period of darkness}circadian rhythm {Ans: A physiological cycle of about 24 hours that is present in all eukaryotic organisms and that persists even in the absence of external cues.}abscisic acid {Ans: plant hormone that inhibits cell division in buds and vascular cambium}hormone {Ans: Chemical messengers, mostly those manufactured by the endocrine glands or in plants, that are produced in one tissue and affect another}ethylene {Ans: A gaseous plant hormone that promotes fruit ripening and opposes auxins in its actions}photoperiod {Ans: the period of time each day during which an organism receives illumination; day length}photochromes {Ans: plant light receptors}herbivores {Ans: Consumers that eat only plants}cytokinesis {Ans: Division of the cytoplasm during cell division}gibberellins {Ans: Plant hormones that promote stem and leaf elongation}short-day plants {Ans: plants that flower when a light period is shorter than a critical length}auxin {Ans: a plant hormone that promotes root formation and bud growth}tropism {Ans: A growth response that results in the curvature of whole