Study Guide for Exam III 1. You are responsible for all six local tree species, including one new one: baldcypress. Bald Cypress Taxodium distichum Makes knees Swamp lover Male and female cones – monoecious Tulip Poplar Liriodendron tulipifera Tip of leaf truncated Petiole emerges first Perfect flowers Longleaf Pine Pinus Palustris Huge pinecones 5 year grass stage Loblolly Pine Pinus Taeda Short needles Doesn’t need fire Red Maple Acer rubrum Glaucus back Helicopter tree Red petiole Eastern Redbud Cercis Canadensis Heart shaped leaves Papilionaceous flowers Cauliflory Plant nutrition 2. You should be able to name at least three plant macronutrients, other than carbon, hydrogen and oxygen. You do not need to memorize the micronutrients. How do plants obtain nutrients? Nitrogen (leafy growth, dark green color), Phosphorus (encourages plant cell division), Magnesium Roots take up water with dissolved nutrients in it. 3. What roles does the ATPase proton pump play in nutrient uptake by plants? (see last item below) What is meant by “cation exchange,” what problem does it solve, and how does it occur? - Proton gradient established by ATPase proton pump creates a negative charge within the cell, which attracts positive ions that then enter the cell through membrane channels - Other nutrients enter through symporters by cotransport with protons - Cation exchange: protons pumped into the soil from the roots replace positive ions clinging to soil particles, releasing them for uptake - Plants trade protons for cations of essential nutrients - Soil pH decreases - Accomplished by ATPase proton pumps 4. How do root cells get the ATP they need for these active mechanisms? The glucose made during photosynthesis is transported to the roots during respiration, which can then be used for ATP. You should be able to describe some specialized systems by which certain plants obtain nutrients (see below): 5. In what kinds of habitats do carnivorous plants tend to live? What kinds of soils? What light levels? What do they gain from their prey? Approximately how common are they? carnivorous plants: - 600 carnivorous plant species worldwide (relatively uncommon when compared to non-carnivorous plants) -gain nitrogen and phosphorus - Found in nutrient poor habitats: acidic, boggy soils - indirect light - Ex: Pitfall traps/Sarracenia, pitcher plants with 4 zones: nectar secretion, slippery surface, digestive glands that secrete enzymes into the pitcher, absorption of nutrients from prey due to no cuticle 6. What are Rhizobia? With what types of plants do they form mutualistic relationships and how does it occur? How does each partner in the mutualism benefit? What does it mean to “fix nitrogen”? By what other processes is nitrogen fixed? What is leghemoglobin and what role does it play in root nodules? - Nitro fixing bacteria - They form relationships with legumes/root hairs with legumes - o Colonizing root hairs of legumes and induce formation of root nodules that provides suitable environment for rhizobia - o Rhizobia convert atmospheric nitrogen into ammonia and nitrates via nitrogen fixation - o Ammonia is used to synthesize proteins and other molecules plants get fixed nitrogen and can thrive in nitrogen poor soils the rhizobia receives sugars and has protection from the root nodules - transforming atmospheric (N2) into ammonia (NH3) and nitrate (NO3-) - lightning and UV rays, industrial fixation: Haber-Bosch process oxygen carrying protein found in the nitrogen fixing root nodules of legume plants (similar to hemoglobin in animal blood but has diff function) - o Acts as an oxygen carrier and maintains low O2 levels in the root nodules -> which makes the environment suitable for nitrogenase activity by rhizobia 7. What are mycorrhizal relationships? How does each partner benefit? How common are mycorrhizal relationships? How are orchids obligately linked to mycorrhizae for survival? They are mutualistic symbiotic associations between fungi and plant roots - fungi helps plant roots access phosphorus and nitrogen and the fungi receives sugars supplied by the plant - Very common - o Orchids have no endosperm and need fungal symbionts to germinate and establish seedlings. - o Fungi provides carbon to the seedlings and colonize orchids until they can photosynthesize by themselves 8. What is meant by an obligate vs. a facultative plant parasite? A hemiparasite? You should know the mechanisms by which some of the parasitic plants we covered parasitize their hosts. - Obligate plant parasite: parasitic plant that relies entirely on the host for survival and reproduction. They can’t complete life cycle without parasitizing the host. Has specialized structures for attaching and extracting resources from host plants - Facultative plant parasite: plant parasite that can survive and reproduce as a parasite and independently of host plant. Not entirely reliant on the host to survive. Has ability to photosynthesize and obtain nutrients by themselves and may opportunistically parasitize other plants for additional resources - Hemiparasite: partial parasite that can photosynthesize and obtain nutrients by itself and also parasitizes other plants for additional water and nutrients. Has degree of independence from host but still relies partially on parasitism for survival and growth. Has haustoria which attaches to roots of host plants to obtain water and nutrients - Mechanisms by which some parasitic plants parasitize their hosts:haustoria Crop evolution 9. What does it mean to domesticate a plant? How does domestication differ from cultivation?o Cultivation: Growing and maintaining plants for human usage and can be wild or domestic plants Domestication: Selectively breed and modify wild plants or animals over generations to better suit human needs/preferences 10. What are some common traits that evolve during the process of plant domestication? What is meant by a “non-shattering” phenotype? See the ICE exercise on this topic, in which you considered the adaptive advantages of traits for the wild relative and for humans. o Evolution of non-shattering seeds= seeds that remain on the plant after they mature. In wild ancestors, seeds were released from the plant when mature o Non shattering phenotype is caused by mutations that remove the abscission layer a line of cells that undergo apoptosis when seed is mature 11. Where and approximately when did agriculture begin? Earliest: 10,000 years ago, in fertile cresent Families For each of these you should know the scientific name (common name not required), major economic products, and key diagnostic traits presented in class. You are responsible for new terms presented that describe specific traits of plant families. These are listed after each family. You might be given a list of diagnostic traits and asked which family they describe. You might be asked to provide two diagnostic traits for a family. You might be given a list of economically important crops and asked to name the family to which they belong. You might be asked to provide two crops for a given family. You might be asked to identify the plant family from a drawing or picture of a plant with a flower. To learn family traits, you’ll need to refresh your memory of basic plant terms, e.g.: zygomorphic vs. actinomorphic flowers, superior vs. inferior ovaries, opposite vs. alternate leaves, determinate vs. indeterminate inflorescences Asteraceae: (Specialized terms that you are responsible for are listed after each family, but these are not meant to be complete lists of diagnostic traits) Asteraceae specialized terms: pappus, involucre, disk and ray flowesr, head (inflorescence type) Brassicaceae specialized terms: tetradynamous stamens, crucifer shaped flowers Cucurbitaceae terms: vine Fabaceae specialized terms: papilionaceous flowers, legumes, pulvinus Lamiaceae Poaceae specialized terms: sheath, blade, awn, node Rosaceae specialized terms: pome, drupe Solanaceae Big picture review material: Because there was still some confusion from many of you on the last exam, and because for many of you this will serve as your “final exam”, I’ll include a couple of questions that test your understanding of energy flow in plants. We reviewed this in ICE 18: Proton gradients Light dependent reactions of photosynthesis: lightproton gradientATP How and where is one created during the light dependent reactions? What source of energy is used to create it during the light dependent reactions? What is the energy in this proton gradient used for? How else can a proton gradient be created? ATPproton gradientcellular process Be able to explain how it is used in nutrient uptake (see above) Be able to describe one additional mechanism of your choice where plants use ATP to create a proton gradient to accomplish some task
