Which conditions have the higher rate of transpiration? Light or dark: Humid or dry: Breezy or still air: Hot or warm: light (need CO 2 for photosyn.) dry (lower H 2 O potential out) breezy (greater evaporation) depends...hot may close stomata to conserve H 2 O T/F (correct if false) Plants are more closely related to fungi than algae. False. Plants have a more recent common ancestor with photosynthetic algae. List several key plant adaptations (traits) to life on land. vascular system seeds pollen grains waxy cuticle fungal mutualism Describe plant meristems. Where are they located? perpetually embryonic cells found at tips of roots and shoots (apical vs. lateral) 1
Identify structures 5/6 and state their function. Xylem (transport H2O + minerals) Phloem (transport sugars, solutes, organic compounds) Identify cells at #4. Describe what occurs there. Gas exchange (CO 2 in, O 2 out H 2 O evaporates from cell surfaces Photosynthesis T/F (correct if false) The first terrestrial plants did not have xylem or phloem. True. Primitive plants such as mosses do not have a vascular system. If guard cells in a plant were deficient in K +, which of the following would be most likely to occur? a. Wilting would become more likely. b. Photosynthesis would decrease. c. Transpiration would increase. d. Food transport would decrease. B no K+, H2O leaves guard cells, stomata close, no CO2 enters 2
Several factors account for the movement of water up xylem vessels. Which single factor is most important in pulling water toward the top of a tall tree? a. Atmospheric pressure b. Osmosis in the root c. Capillary action d. Evaporation of water through stomata D Name this characteristic plant response: Phototropism Describe 2 conclusions you can make from these observations: Explain the significance of these observations. Cells in tip of seedling respond to light A substance made/ released from cells in tip travels to other cells High concentration of chemical (auxin) affects cells on the "dark side" of plant, causing elongation. 3
Describe 2 ways plants respond to cold stress: Increase fluidity of membranes (more unsat'd f.a.) Increase solutes in cytoplasm (freezing point depression) Produce antifreeze proteins All of the following enhance water transport in terrestrial plants EXCEPT: a. Hydrogen bonds linking water molecules b. Capillary action due to adhesion of water molecules to the walls of xylem c. Evaporation of water from the leaves d. K + being transported out of the guard cells D Under conditions of bright light, in which part of a transpiring plant would water potential be lowest? a. Xylem vessels in the leaves b. Xylem vessels in the roots c. Root hairs D d. Spongy mesophyll of the leaves 1) 2) Name/describe the membrane proteins: 1) Proton pump: H+ transported against conc. gradient...sets up membrane potential 2) Cotransporter: Diffusion of H+ provides energy required to pump sucrose. 4
Explain the need to water an area where you have just planted seeds. What type of environment would result in the greatest rate of transpiration? Water insoluble Water soluble Watering seeds washes away abscisic acid (ABA), removing hormonal control of dormancy, allowing gibberellins to promote growth. a. Cloudy, humid conditions b. Warm, humid conditions c. Warm, light breezy conditions C d. Cool, humid conditions How can fruit ripening be regulated at grocery stores or at home? grocers use canisters of ethylene (C 2 H 4 ) gas to promote ripening fruits can be placed in brown paper bags to promote ripening (C 2 H 4 ) gets trapped Chrysanthemums are considered "short day"/ "long night" plants. How is it possible to purchase flowering mums during other times of the year when day length is long? 5
What is the name for these types of plant responses? Photoperiodism 6