2 Introduction Plants are placed into 2 groups based on structural and functional similarities, but all plants share the followingcharacteristics.A. EukaryoticB. MulticellularC. Have organs and organ systemsE. Have cell walls composed of celluloseF. Are autotrophicG. Photosynthesis takes place in the chloroplast of plant cellsCO2 + H2O C6H12O6 + O2H. All are non-motileSpecial adaptations are therefore required for reproduction
3 Plant Structure and Growth A. Roots – Functions:Anchor the plantAbsorb water and mineralsTransport these materials to the stemSome plants store food in rootsEach root has root hairs, increase surface area for water absorption
4 Plant Structure and Growth B. Stems – Functions:Support for the plantTransport water and mineralsModified stem for storage of foodExample: Potato
5 Plant Structure and Growth C. Leaves – Functions:Main organ for photosynthesisLarge surface area for maximum light absorption
6 Plant Structure and Growth Structure of Leafa.) Cuticle: waxy covering to prevent water lossb.) Epidermis: Outermost layer of cells; prevents injury, infectionc.) Mesophyll: Photosynthetic layer of leaf1. Palisade layer: upper portion of mesophyll with closely packed cells; siteof most photosynthesis2. Spongy layer: Underside of leaf; loosely – packed cells allow for gasexchange of CO2 and O2d.) Vein: xylem and phloeme.) Stomata: Opening in underside of leaf that allows CO2(carbon dioxide) to enter and O2 (oxygen) to exitf.) Guard cells: Control the size of stomata. Work to preservebalance between allowing for gas exchangewithout losing too much water. “Plant sweat” isknown as transpiration.
8 Plant Structure and Growth D. Plant TransportThe 2 types of vascular tissue:1. Xylem: transports water and minerals from the root tothe rest of the plant2. Phloem: transports “food” (glucose) from the leaves to
9 Plant Structure and Growth E. Plant growth1. Primary growth: Life longgrowth occurs at the tip ofthe stem and the end of theroots2. Secondary Growth: Treesand some other plants have asecond type that allows themto grow in width or girth.
10 Plant Structure and Growth F. SeedsA seed consist of an embryo surroundedby a tough protective coat.Dicot Seed
11 Plant Classification Plants are classified into 2 basic groups based on whether they contain vascular tissue.
12 Plant Classification A. Bryophytes – No vascular tissue present mossesA. Bryophytes – Novascular tissue presentDepends on water for reproductionNo vascular system,therefore no tallerthan 20 cmExamples: mosses,hornworts,liverwortsliverwortshornworts,
13 Plant Classification B. Tracheophytes – contain vascular tissue Grow tallerLive in drier climatesThe tracheophytes are further subdivided based on the presenceor absence of pollen, seeds and fruit.1. Pterophytes2. Gymnosperms3. AngiospermsPterophytesGymnospermsAngiosperms
14 Plant Classification 1. Pterophytes – commonly called ferns No pollen No seedsNo fruitsFound predominantly in moist climates because the sperm must swim to the egg cell
15 Plant Classification 2. Gymnosperms – “naked seed” Have pollen Have seeds not protected by fruitNo fruitCones presentExample: Largest group is the conifers which includes pines, spruce, cedarHave common characteristic leaves called needles, which are modified to prevent water loss and minimize ice build – upHave “flying sperm” or pollen, so they are no longer tied to water for reproduction
16 Plant Classification 3. Angiosperms Most complex and adaptable Most successfulHave pollenHave seedsHave fruitMature ovaryContains one or more seedsProvides embryo with protectionIncreases seed dispersal
17 Plant Classification Angiosperms cont. Have flowers It enhances pollinationParts of the flowerStamen – male reproductive organAnther – where pollen is produced, which contain the sperm cellsFilament – holds up the antherPistil – female reproductive organStigma – sticky to hold pollenStyle – holds up the sigmaOvary – where the egg is produced and fertilizedPetal – colorful and / or scented to attract pollenators