BY 124 1st Edition Lecture 6 Outline of Last Lecture Chapter 36 I Transpirational Pull Cohesion Adhesion Mechanism II Mechanisms of Stomatal Opening and Closing III Movement Through Phloem IV Sieve Tubes Chapter 37 I II III IV V Essential Elements in Plants Cation Exchange Soil Bacteria and Nitrogen Plants That Have Relationships With Another Organism Nutritional Adaptations in Plants Outline of Current Lecture Chapter 37 I Nutritional Adaptations in Plants cont Chapter 39 I II III IV Signal Transduction Pathway Example of STP Plant Hormones Plant Movement Current Lecture Chapter 37 cont I Nutritional Adaptations in Plants cont a Carnivorous plants insectivorous 1 Live in Nitrogen poor soils therefore have to get nitrogen from exoskeleton of insects 2 Usually found in sandy soils along coast 1 Pitcher plants These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute a Modified leaves downward pointing hairs b Water nectar in pitcher c Insect cannot get out once in due to the downward pointing hairs 2 Venus fly traps a Proton pumps cause trap to open close 3 Sundews a Use sticky substances protrusions to trap insect and then another protrusion releases chitin to get nitrogen 4 Bladderworts a Float on surface of water b Aquatic insect triggers trap water is sucked into bladder of plant insect is pulled in with it and will then remain there to be broken down Chapter 39 Plant Responses to Internal and External Signals I II III Remember hormone to excite or respond Signal Transduction Pathway Figure in Chapter Review of 39 1 a Reception i Hormone binds to receptor 1 Small because it needs to get through the cell wall b Transduction i Relay proteins and messengers pass info c Response i Activation of cellular responses Example of Signal Transduction Figure 39 4 a Remember kinases phosphorylate b Small amounts of hormones can still give good response c How hormone responds in plants depends on i Site of action ii Size of embryo iii Concentration of hormone iv Ratio of hormone compared to other hormones Plant Hormones a Auxin IAA to grow any organism that will elongate effects coleoptiles i IAA indoleacetic acid most important type form of auxin ii Experiments Figures 39 5 and 39 6 1 Darwin and Darwin 1880 a If tip taken off doesn t respond to light b If opaque cap no response to light c Transparent cap responds to light d Opaque shield on curve stem responds to light 2 Boysen Jensen 1913 a Gelatin put all across the cut off tip responds due to the permeability of the gelatin b Mica put all across the cut off tip does not respond due to the impermeability of the mica iii Polar Auxin Transport Chemiosmosis 1 Carriers for auxin are located at the base of the cell 2 Auxin travels cell to cell in coleoptile 3 When A negatively charged auxin molecule moves through transport carrier it picks up H and becomes AH a This allows it to move a little more freely in the membrane 4 Loses H when it leaves the cell membrane a ATP puts the H back into cell membrane 5 A moves to base of cell and repeats process iv Figure 39 8 shows how plant bends in response to light because of auxin v Growing patterns 1 Phototropism moves in response to light 2 Gravitropism moves in response to gravity Figure 39 24 a Statoliths settle and dictate how the plant will root vi Prevents lateral buds Figure 39 9 1 Auxins keep potatoes from budding 2 Fruit only occurs after fertilization a Auxin produces a fruit without seeds vii Leaf Abscission auxin retards 1 This is what happens when a plant seals off leaf by cutting off supply viii Involved in secondary growth ix Helps with growth of lateral and adventitious roots x Affects vascular cambium b Gibberellins fungus foolish seed disease i Forms long shoots ii Stimulates fruit development iii Cause embryos to make alpha amylase to break down starch to make sugar for baby plant to grow c Brassinosteroids like cholesterol i Reduce cell elongation and division d Cytokinins come from roots i Degradation products of nucleic acids 1 Modified forms of adenine ii Most important zeatin comes from corn iii Causes cell division iv Work by causing transcription and translation v Work with auxins IV 1 If auxin decreases and cytokinins increases shoot and leaf growth 2 If auxin and cytokinins root growth 3 If auxin cytokinins growth but no differentiation vi Anti aging e Abscisic acid ABA i Inhibits growth inhibits division in vascular cambium ii Stomata close hen plant is stressed iii Causes leaves to fall off f Ethylene stress hormone i Triggered by auxin and ABA ii Speeds ripening rotting process iii Promote leaf abscission iv Inhibits root elongation v Flowering vi Leads to changes that cause death in plant 1 Apoptosis a Like xylem found in xylem Plant Movement Figure 39 25 a Phototropism b Gravitropism c Thigmotropism growth by touch i Thigmomorphogenesis if I m touching you I m going to affect your shape