BIOL 1442 1st Edition Exam #1 Study Guide Chapter: 3Plasticity- the ability to alter itself in response to its environment because plants can’t move: higher variability than animals- size, position of branches, rootsPlant Body- cell-basic unit, tissue-specialized cells, organ-several tissues carry out a functionPlant Organs- roots, stems, leaves; the shoot system(stem & leaves) vs the root system (roots): - shoot system- sunlight & CO2 - root system-water & mineralsRoots- anchor in soil, absorbs minerals, H2O and O2, storage- tap root: MAIN vertical root that grow deep to access water from bottom of the ground;ex; carrots, beets, turnips: store sugar/starch- branch roots: many lateral rootsFibrous Root System- seedless vascular pants, monocots (some are grass like) roots grow from the stem- do not grow deep: prevent erosion- each small root forms lateral rootsAdventitious- plant organ growing in an unusual locationRunof- roots are critical for soil stabilization but small plants with less extensive rot systems cannot hold run-ofRoot hairs- MOST H2O & mineral absorption in root tips; root hairs increase surface area; don’t last and are replacedModified Roots- - Prop roots: maize (corn) can grow 10 feet- Aerial roots: fig roots, buttress roots with hallow space between them in tropical rainforests withshallow soil- Pneumatophores: air roots to obtain O2: mangrovesStems- consists of nodes and internodes- node: point where leaves attached- internodes: segments between nodesApical bud (terminal)- TOP located at shoot tipThese 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.- apical dominance: axillary bud growth inhibited by apical bud- if apical bud not there, axillary buds grown LATERALLY: thick shrubsAxillary bud- can form a lateral shoot; branch, stem or flower- not growing in young shootsModified Stems- - rhizomes: horizontal shoot grow below surface: separate to be a clone; ginger- stolons: (runners) horizontal shoot along surface; strawberry plants- tubers: enlarged ends of rhizomes or stolons for storing food; potatoes - bulbs: vertical underground shoots, enlarged leaves that store food; onionLeaves: main photosynthetic organ; made of blade and petiole(stem)Grasses and monocots lack petiolesVeins- vascular tissue of leavesMonocots- parallel veins vsEudicots- branching veinsLeaf Morphology- used to identify plants- simple leaf: petiole and single blade- compound leaf: petiole, multiple blades called leaflets- doubly compound leaf: petiole, each leaflet is divided into smaller leafletsModifications- Some leaves specialized for support, protection, storage, reproduction- Tendrils: to climb on things; cucumber- Spines: for protection, photosynthesis by stem- Storage leaves: store water; aloe vera- Bracts: attract pollinators look like flowers- Reproductive leaves: adventitious plantlets fall and take root in soilPlant’s Tissue System- each organ has dermal, vascular, and ground tissuesDermal (1)- plants outer protective covering (skin) protect physical damage, water loss, and pathogens- nonwoody: epidermis: layer of tight cells cuticle: waxy coating on surface to prevent water loss- woody: periderm: protective & replace older epidermisex: root hairs on root tip and trichomes: hair like outgrowths of the shoot epidermisVascular Tissue System (2)- carries out long distance transport of materials between roots & shoots- Xylem: transports water & dissolved minerals UPWARDS from roots into shoots: one direction- Phloem: transports nutrients from where they are made LEAVES to where they are needed ROOTS: bidirectionalGround Tissue System (3)- storage, photosynthesis & support- pith: ground tissue internal to vascular tissue; dark part- cortex: ground tissue external to vascular tissuePlant Cells- specialization in structure & function- primary cell wall: thin / flexible- secondard: between plasma membrane & cell wall: lots of cellulosea.) parenchyma cells: ONLY type of cells that can become other cell types- perform most metabolic functions of the plant- synthesize & store organic molecules- large central vacuoleb.) collenchyma cells: young, still growing parts, flexiblec.) sclerenchyma cells: opposite of collenchyma; support plant, rigid cells, occur in regions have stopped growing- sclereid: short, irregular, seed coats- fibers: long, threadliked.) water conducting cells- xylem: dead when functional- tracheids: most common: vascular tissue- vessels elements: with perforiation platee.) sugar conducting cells- phloem: transport nutrients long narrow cells: sieve tubePlant Growth: occurs whole lifetime- indeterminate growth: growth not limited to embryonic/juvenile- determinate growth: stop growing after reach certain size- plants have embryonic, developing and mature organsLife cycle- - annuals complete life cycle in 1 year- biennials: 2 growing seasons; grow big and then reproduce- perennials: live many years: immortalMeristems- perpetual embryonic tissueapical meristems: tip of roots; primary growth: elongate shoots and roots- includes epidermis, ground, vascular- herbaceous (entire)- woody (young)- primary growth of root:- root cap- covers tip: protects apical meristem, secretes slime, lubricate soil- growth occurs behind root tip: zone of cell division: includes apical meristem: cells produced through mitosiszone of elongation: elongate & lengthen; push root in soilzone of maturation: cells diferentiate & specialize- endodermis: innermost layer of cortex; selective barrier for vascular cylinder- stele is vascular cylinder w/xylem and phloem- lateral roots arise within percycle: outermost cell layer in vascular cylinder- intercalary meristems: base of leaf blades and stem internodesvascular tissue of each leaf is continuous with vascular tissue of stem- leaf traces: connections from vascular bundles in stem- veins: bring xylem & phloem in close contact w/photosynthetic tissue- bundle sheath: protective layer covering veins act as skeletonlateral meristems: along length of roots and stems; secondary growth: in thicknessSecondary growth: adds thickness in woody plants- Vascular cambium: adds layers of vascular tissueWOOD: secondary xylemBARK: periderm and phloem2nd xylem INTERIOR 2nd phloem EXTERIOR (never more than 2 layers of phloem)elongate parallel to axis of rootvascular rays: perpendicular to axis, connect 2nd xylem w/2nd phloem- early wood spring large