Lab Assignment Due in last Plant Lab Assignment graded by GSI each lab Plant Hormones Constituents Nutrition Describe the following information for 10 different foods you have eaten 1 Name of food 2 Major group this food comes from Angiosperm Monocot or Eudicot Gymnosperm or Protist e g red algae brown algae Cyanobacteria e g Spirulina 3 What plant part is consumed e g leaf stem root flower fruit seed 4 What plant tissue and or cell type is consumed Bio 1B Fall 06 Professor Carlson 1 Plant Hormones Chemical Communication Table 39 1 2 Plant Hormones Chemical Communication Table 39 1 Gibberellic Acid Table 39 1 Fig 39 10 11 Seed germination Fig 39 11 Bud germination Stem elongation Flowering Fruiting Fig 39 10 Gibberellic Acid was originally isolated from the fungus Gibberella fujikuroi which is a plant pathogen on rice that resulted in unusually long shoots 3 Plant Hormones Chemical Communication Table 39 1 Auxin indole acetic acid Campbell Table 39 1 Fig 39 7 Apical dominance Phototropism Stem cell elongation Fig 39 8 Gravitropism 4 Plant Hormones Chemical Communication Table 39 1 Cytokinins Table 39 1 Fig 39 9 Promote cell division lateral bud outgrowth Inhibit leaf senescence Brassinosteroids Table 39 1 Steroid hormone Supports growth of xylem Supports elongation of stems pollen tubes Inhibits leaf abscission 5 6 Plant Hormones Chemical Communication Table 39 1 Plant Hormones Chemical Communication Table 39 1 Abscisic Acid ABA Table 39 1 Inhibits growth stem elongation Supports seed dormancy Fig 39 12 Inhibits seed germination Closure of stomata in response to water stress Ethylene Table 39 1 Promotes fruit ripening Promotes leaf abscission Fig 39 16 Promotes senescence Inhibits stem elongation Fig 39 13 Inhibits gravitropism 7 Plant defense mechanisms 8 Plant defense mechanisms Hormones that Respond to Tissue Damage and Trigger Plant Defenses Phytochemical repel herbivores microbes Oils from variety of herbs spices repel insects oligosaccharins Pine sap inhibits insect pests e g bark beetles jasmonates Tannins resins concentrate in heartwood of trees to prevent insect microbial infestation and rotting systemin Many alkaloids e g caffeine nicotine morphine and cocaine repel herbivores microbes salicylic acid 9 10 11 12 13 14 Plant defense mechanisms Barriers to Entry Cuticle Fig 35 17 matrix of cross linked lipid molecules impregnated with extremely long chained lipids Spines thorns prickles Fig 35 7b 15 16 17 18 Nutrient Acquisition Photosynthesis Figs 10 3 10 10 page 183 Occurs in chloroplasts in green plant tissues Leaf parenchyma cells contain 40 50 chloroplasts Chlorophyll pigments in plants convert energy from sunlight to chemical energy in the form of ATP NADPH an electron carrier Carotenoids carotene and xanthophylls absorb wavelengths of light that are not absorbed by chlorophyll and extend the range of wavelengths that can drive photosynthesis Heterotrophs obtain nutrients from other organisms animals fungi Autotrophs produce own food through photosynthesis green plants 19 20 21 22 Photosynthesis Equation Photosynthesis Equation 6CO2 12H2O light energy C6H12O6 6O2 6H2O C6H12O6 glucose 6CO2 12H2O light energy C6H12O6 glucose 6O2 6H2 Simplest Form of Photosynthesis Equation CO2 H2O light energy CH2O O2 H2O Light dependent reactions Light energy H2O chemical energy ATP NADPH O2 oxygen in O2 derived from oxygen in H2O 23 Light independent reactions Calvin Cycle Chemical energy ATP NADPH CO2 CH2O Carbon in sugar is derived from carbon in CO2 24 Types of Photosynthesis C3 plants Fig 10 18 Calvin cycle takes place in each cell Calvin was a professor at UC Berkeley C3 plants use Calvin cycle Use rubisco enzyme for initial fixation of carbon Adaptation to Dry Environments C4 plants CAM plants The CO2 is initially fixed into three carbon sugars 25 Adaptation to Dry Environments Adaptation to Dry Environments CAM Plants Fig 10 20 succulents that live in conditions of high light intensity and water stress stomata are closed during the day to prevent water loss C4 plants Fig 10 19 10 20 certain cells in the leaf sequester CO2 largely depend on night time accumulation of CO2 use PEP carboxylase for initial fixation of carbon to produce 4 carbon organic acids favored in dry climates because it enhances photosynthetic efficiency by limiting the loss of carbon and ATP to photorespiration 26 store huge quantities of CO2 in the form of sugars and sequester them in vacuoles 27 during the day these sugars are metabolized to release CO2 and feed into Calvin cycle 28 Gas exchange between atmosphere and plant via stomata in leaves Stoma stomata plural guard cells pores Fig 10 3 Guard cells pair of bean shaped cells Pore opening between guard cells 29 30 Gas exchange between atmosphere plant via stomata in leaves O2 produced by plant released out of stomata pores into atmosphere where it is available for humans animals to breath H2O released out of the pores via evapo transpiration in some species e g coastal redwoods Douglas Firs during high fog conditions H2O can be absorbed from the air into the leaf through the stomata pores to provide H2O for the plant During photosynthesis when CO2 levels within leaf fall below optimal levels the stomata open CO2 diffuses in from 31 atmosphere CO2 in Atmosphere Global Warming 32 Sugar produced by photosynthetic organisms fuels cellular respiration and growth of plant sugars are typically stored in the form of starch long chains of glucose molecules fossil fuel burning deforestation in past 100 years atmospheric CO2 atmospheric CO2 contributes to global warming transported in the form of the disaccharide sucrose glucose attached to fructose or monosaccharide glucose or fructose Photosynthetic organisms are eaten by animals and fungi Photosynthesis by green plants removes CO2 from the atmosphere sequesters carbon in wood 33 Plant Pigments Photosynthesis Directly or indirectly many organisms get their energy from photosynthesis 34 Flavonoid Pigment as Plant Suncreen Carotenoids Carotenes e g beta carotene in carrots lycopene in tomatoes Xanthophylls e g zeaxanthin which gives corn yellow color Flavonoids absorb ultraviolet radiation which Carotenoids in chloroplasts extend range of wavelengths that drive photosynthesis Protect chlorophyll by acting as anti oxidant and destroy free radicals that damage the chlorophyll molecules beta carotene also works a beneficial anti oxidant in humans protects leaves stems from damaging effects of UV During most of
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