Chapter 7 BOT3015L Regulation of Gas Exchange of Terrestrial PlantsTodayThe main ideas from last week’s look at the anatomy of the angiosperm plant bodyPowerPoint PresentationReview of photosynthesisTransport SummarySlide 7Leaf observations What characteristics of leaves make them well-adapted for their function?Slide 9Morphological Adaptations Responses to Water AvailabilitySlide 11Slide 12Pitcher plant (Sarracenia)Slide 14Three tissue systems in leaves tooStomata adaptations to terrestrial environmentsSlide 17Slide 18Slide 19Slide 20Slide 21Slide 22Gas Exchange Open & Closed StomataGas Exchange (g) Ion Transport—stomatal openingGas Exhange (e) Stomatal swellingGas Exchange (j) Ion Transport—stomatal closingGas Exchange ion transport—ABA actionSlide 28Slide 29Experimental DesignIn notebook and checked before you leaveChapter 7BOT3015LRegulation of Gas Exchange of Terrestrial PlantsPresentation created by Danielle SherdanAll photos from Raven et al. Biology of Plants except when otherwise noted•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationToday•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationThe main ideas from last week’s look at the anatomy of the angiosperm plant bodyPhotosynthesis primarily occurs in chloroplasts of leavesLilac (Syringa)Review of photosynthesisNote that this is a depiction with some gaps and misrepresentations for summary purposesTriose phosphatesTransport SummaryA=absorption / assimilationL=loadingU=unloadingI=interchangeToday•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationLeaf observationsWhat characteristics of leaves make them well-adapted for their function?Today•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationMorphological AdaptationsResponses to Water AvailabilityWaterlily (Nymphaea)Note the misnomer, waterlilies are not in the Liliaceae family Note the abundant of air spaces.This plant grows in water.Modified from Outlaw lectureMorphological AdaptationsResponses to Water AvailabilityNote large volume-to-surface area ratio ideal for dry environmentSpines (modified leaves) protect the water-filled plant body from predationFerocactusExample of turgor control of quick responses in highly specialized leavesPhoto by Jean Burns at Hosford bogPlants in motionVenus fly trapVenus fly trap (Diaonaea)Pitcher plant(Sarracenia)Example of highly specialized leavesPhotos from www.serracenia.comToday•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationLilac (Syringa)Cross-section, midvein of leafThree tissue systems in leaves tooCross-section, blade of leafLilac (Syringa)Isolated epidermis stained with neutral red (vital stain that stains compartments of living cells)Stomataadaptations to terrestrial environmentsToday•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationStomata typical of dicotsStomata typical of monocotsPotato (Solanum) Maize (Zea)Scanning electron microscope imagesScanning electron microscope imageStomata and trichome of tobacco (Nicotiana)Morphological AdaptationsResponses to Water AvailabilityBanksiaNote sunken stomata.. . . Sunken stomata increase the distance from the moist leaf interior to the bulk atmosphere. Flux Equation!Modified from Outlaw lectureOleander (Nerium)Trichomes and sunken stomataMorphological AdaptationsResponses to Water AvailabilityToday•Review photosynthesis and bulk transport in plants•Observing leaf morphology•Examples of highly modified leaves•Leaf anatomy•Stomata, adaptations to terrestrial environments•Stomata aperture changes•Further understanding of stomata by experimentationGas ExchangeOpen & Closed StomataStomata animationModified from Outlaw lecturePhotos from Outlaw’s lab and also featured on the cover of the scientificjournal Archives of Biochemistry and BiophysicsFava bean (Vicia)Gas Exchange (g)Ion Transport—stomatal openingInside cellMembraneProton extrusion makes membrane potential more negative and acidifies apoplast.Water influx Potassium uptake.Thermodynamics: MPMechanism: MP & wall acidification activate the Kin channelModified from Outlaw WH, Jr. Integration of cellular and physiological functions of guard cells. CRC Crit Rev Plant Sci 22: 503-529E. Water influx increases pressure, but water is incompressible, so guard-cell volume increases. The increase results from stretching of the dorsal wall.A. Guard-cell symplast accumulate solutes from guard-cell apoplast.C. Radial micellation of cellulose microfibrils prevents increase of cell diameter.B. Water flows into guard cells osmotically.MEMBRANECELL WALLD. Inner wall is strong and cannot be stretched.Gas Exhange (e)Stomatal swellingModified from Outlaw lectureGas Exchange (j)Ion Transport—stomatal closingMembraneInside cellB. Potassium efflux.Thermodynamics: MPMechanism: MP activates the Kout channelA. Anion efflux shifts the membrane potential to a less negative position.Modified from Outlaw WH, Jr. Integration of cellular and physiological functions of guard cells. CRC Crit Rev Plant Sci 22: 503-529ABA activates the Kout channel via cytosolic alkalinization.Gas Exchangeion transport—ABA action MembraneInside cellABA may be made in roots and transported to shoots, or made by leaves, or even by guard cells.ABA activates the anion