Môn Sinh học - Chapter 35: Plant structure, growth, and development

Ch. 35 Warm-UpDraw and label the 3 main organs of a plant.What are 3 ways that plant cells differ from animal cells?Most H2O and minerals taken up from the soil by a plant are absorbed by _______.The main photosynthetic organs of a plant are the __________.Ch. 35 Warm-UpList the 3 types of plant tissues. What is the function of each type?What are meristems? Where are they located in a plant?What effect does “pinching back” a house plant have on the plant?Chapter 35Plant Structure, Growth, and DevelopmentWhat you must knowThe function of xylem and phloem tissue.The anatomy of a leafThe anatomy of a rootIntroduction to PlantsKingdom: PlantaeCell wallAutotroph (photosynthesis)MulticellularAngiosperms (flowering plants)~90% plantsProduce seeds within a fruitKey adaptations: flowers & fruitsPlant OrganizationOrgansRootsStemsLeavesTissuesDermalVascularGroundCell TypesXylemPhloemParenchymaAbove groundStems, leavesUnderground (usually)RootsShootsystemRootsystemI. Plant OrgansA. RootsAnchors plant, absorbs H2O & minerals, stores sugars/starchesRoot hairs – tiny extensions of epidermal cells, increase surface area for H2O and mineral absorptionMycorrhizae: fungus + plant root symbiotic relationshipRoot hairsFibrous Root(scallion)Taproot(carrot)Fibrous RootsMat of thin roots spread just below surfaceShallowIncreased surface areaTaprootsOne thick, vertical rootMany lateral (branch) rootsFirmly anchorsStores foodModified RootsMangrove Forest in FloridaB. StemsFunction: display leavesTerminal bud: growth concentrated at top end of stemSecretes hormone to prevent growth of axillary buds; growth directed upward, toward lightAxillary buds – located in V between leaf and stem; forms branches (lateral shoots)Pinching/pruning – removing terminal budModified stemsRunner or stolinAspen, strawberries, grassGrow on surfaceFor asexual reproductionRhizomeIris, ginger, potato, onionGrow undergroundStore food & DNA for new plantTuber: end of rhizomeBulb – underground shootOnion storage leavesC. LeavesFunction: Photosynthetic organpetiolebladeModified leavesII. Plant TissuesA. Dermal TissueSingle layer, closely packed cells that cover entire plantProtect against water loss & invasion by pathogens (viruses, bacteria)Cuticle: waxy layerB. Vascular TissueContinuous throughout plantTransports materials between roots & shootsXylem & PhloemC. Ground TissueAnything that isn’t dermal or vascularFunction: storage, photosynthesis, supportPith: inside vascular tissueCortex: outside vascular tissueIII. Cell TypesXylemConducts H2O and minerals up from rootDead, tubular, elongated cellsPhloemConducts sugar & organic compounds from leaves to other parts of plantLiving cells aid movement of sugar2 Cell Types: sieve tubes, companion cellsXylemPhloemPlant GrowthTypes of Flowering Plants:Annuals – 1 year life cycleBiennials – 2 yearsPerennials – continuous life cycle for many yearsMeristem: perpetually embryonic tissuesCells divide for plant growthApical meristem: growth at tips of roots & buds of shoots; cause primary growth (increase length)Lateral meristem: growth thickens shoots and roots; secondary growthPrimary and Secondary GrowthRoot AnatomyRoot cap: protects meristem as it pushes through soilZone of Cell Division: apical meristem; new cells produced (mitosis)Zone of Elongation: cells elongate; push root tip aheadZone of Maturation: primary growth becomes functionally matureRoot HairsKeyDermalGroundVascularEpidermisRoot hairCortexVascular cylinderZone ofmaturationZone ofelongationZone of celldivisionApicalmeristemRoot cap100 µmPrimary Growth of a RootPrimary Growth of ShootsShoot apical meristem: dome of dividing cells at tip of terminal bud; divide and elongateLeaf AnatomyEpidermis of underside interrupted by stomata (pores), flanked by guard cells (open/close stomata)Mesophyll: ground tissue between upper/lower epidermisParenchyma: sites of photosynthesisSecondary Growth = increase diameterInvolves lateral meristemsVascular cambium: produces secondary xylem (wood)Cork cambium: produces tough covering that replaces epidermisBark = all tissues outside vascular cambiumPrimary and secondary growth in a two-year-old stemEpidermisCortexGrowthXylemrayVascularcambiumPrimaryphloemPithPrimaryxylemPhloem rayEpidermisCortexVascular cambiumPrimary phloemPithPrimary xylemVascular cambiumPrimary phloemPrimaryxylemSecondary phloemSecondary xylemFirst cork cambiumCorkGrowth0.5 mmVascular cambiumSecondary phloemSecondaryxylemTransverse sectionof a three-year-old Tilia (linden)stem (LM)Late woodEarly wood0.5 mmCork cambiumCorkPeridermXylem rayBarkVascular cambiumPrimary phloemSecondary phloemSecondary xylemPeriderm(mainly corkcambiaand cork)Primary xylemPithVascular cambiumSecondary phloemSecondaryxylem (twoyears ofproduction)CorkBarkLayers ofperidermMost recentcork cambiumPrimary and Secondary Growth of a Stem