you light up my life - dr annette m parrott：你照亮我的生命-安妮特博士m派瑞特

Plant TissuesAngiosperms flowering plants The angiosperms are seed-bearing vascular plants In terms of distribution and diversity, they are the most successful plants on Earth The structure and function of this plant group help explain its successMonocots and Dicots same tissues, different featuresParallel veins Netlike veins3 pores1 pore4 or 5 floral parts3 floral parts1 cotyledon 2 cotyledonsVascular bundles dispersedVascular bundles in ringFlowering Plant Life Cycle Double fertilization Meiosis MeiosismicrosporesFemale gametophytepollinationMitosis without cytoplasmic divisionTwo sperms enter ovuleDiploidHaploidPlant Life Histories Annuals complete life cycle in one growing season Biennials live for two seasons; flowers form in second season Perennials grow and produce seeds year after yearMeristems Where Tissues Originate Regions where cell divisions produce plant growth Apical meristemsResponsible for primary growth (length) Lateral meristemsResponsible for secondary growth (width)Apical Meristemsactivity atmeristemsnew cellselongateand start todifferentiateinto primarytissuesprocambium primary vascular tissuesprotoderm epidermisCells that form at apical meristems:ground meristem ground tissuesLengthen shoots and roots:StemAM and RootAMLateral Meristemsvascular cambium secondary vascular tissuesperiderm cork cambiumthickeningIncreases girth of older roots and stemsCylindrical arrays of cellsPlant Tissue SystemsVASCULAR TISSUESGROUND TISSUESSHOOT SYSTEMROOT SYSTEMEPIDERMIS Ground tissue system Vascular tissue system Dermal tissue system Ground Tissue fills space b/t dermis & vascularParenchyma: Primary metabolic function (photosynthesis) Found in roots, stems & leaves Least specialized, thin flexible walls, dont divide unless specializing, respire, store food & waterSchlerenchyma: support w/ thick 2o wall strengthened by lignin Found in stems & leaves generally lack protoplasts Very rigid cell wall, dead at maturity, cannot lengthen scaffolding “fibers” & “Sclereids”Collenchyma: child support Found in stems and leaves Grow and elongate with stems and leaves they support, flexible in young parts of plantcollenchymaparenchyma sclerenchymaMorphology of three simple tissue typesComplex TissuesComposed of a mix of cell typesXylemPhloemEpidermisSimple TissuesMade up of only one type of cellParenchymaCollenchymaSclerenchymaVascular Tissue Phloem: Phood conduction, carries products of photosynthesis to non-photo cells Found in roots, stems, leaves Sieve cells, albuminous cells, companion cells, parenchyma Gymnospersm: sieve, angiosperms, sieve-tube members, connected vertically by sieve plates Alive at maturityXylem: provides water & ion transport from roots to leaves Vessel elements, tracheids, fibers, wood parenchymal tracheids & vessel members, thick w/ secondary wall with lignin Dead at maturity Seedless vascular & gymnosperms have tracheids w/ tapered ends Angiospersm have both tracheids and vessel members wh are continuousXylem Conducts water and dissolved minerals Conducting cells are dead and hollow at maturityvessel membertracheidsPhloem: A Complex Vascular Tissue Transports sugars Main conducting cells are sieve-tube members Companion cells assist in the loading of sugarssieve platesieve-tubemembercompanioncellEpidermis: A Complex Plant Tissue- Covers and protects plant surfaces- Secretes a waxy, waterproof cuticle- In plants with secondary growth, periderm replaces epidermis- protection, increase absorption area in roots, reduces H2O loss in stem & leaves,- Regulates gas exchange in leavesSignaling between Plants and Pathogens water & minerals sugarSHOOT SYSTEMROOT SYSTEMRoot system- anchors the plant- penetrates the soil and absorbs water and minerals- stores foodShoot system- produces sugars by photosynthesis- carries out reproductionShoot and Root Systems:Not independentShoot Development ground meristemprimary xylempithprocambriumcortexprocambriumprotodermshoot apicalmeristemprimary phloemRoots also have meristemsLeaf Gross Structure-Adapted for PhotosynthesispetiolebladeaxillarybudnodebladesheathnodeDICOT MONOCOT Leaves are usually thin High surface area-to-volume ratio Promotes diffusion of carbon dioxide in, oxygen out Leaves are arranged to capture sunlightAre held perpendicular to rays of sunArrange so they dont shade one anotherLeaf StructureUPPEREPIDERMISPALISADEMESOPHYLLSPONGYMESOPHYLLLOWEREPIDERMISone stomacuticleO2 CO2xylemphloemParenchymaCollenchymaMesophyll: Photosynthetic Tissue A type of parenchyma tissue Cells have chloroplasts Two layers in dicotsPalisade mesophyll Spongy mesophyll Leaf Veins: Vascular Bundles Xylem and phloem often strengthened with fibers In dicots, veins are netlike In monocots, they are parallelInternal Structure of a Dicot Stem- Outermost layer is epidermis- Cortex lies beneath epidermis- Ring of vascular bundles separates the cortex from the pith - The pith lies in the center of the stemInternal Structure of a Monocot Stem The vascular bundles are distributed throughout the ground tissue No division of ground tissue into cortex and pithDicotsDicots and Monocots have different stem and root anatomiesGround tissuesystemVascular tissuesystemDermal tissuesystem MonocotsStemsMonocot stems differ from dicot stems in that they lack secondary growth No vascular cambium nor cork cambium Stems usually uniform in diameter Scattered vascular bundles (not in a ring like dicot stems) The Translocation of Phloem the process of movin