PlantAnat.ppt

PlantAnat.ppt

• 1.
  Lecture 3: Plantanatomy and physiology by Edgar Moctezuma, Ph.D.
• 2.
  Today… • Plant Anatomy –Cells – Tissues – Organs • Plant Physiology – Water & sugar transport – Plant hormones • Plant Classification
• 3.
  From smallest tolargest plants
• 4.
  What is plantanatomy? • ANATOMY: study of the structure of organisms… looking at cells, tissues • (Morphology: Study of form) What is plant physiology? • PHYSIOLOGY: study of the function of cells, tissues, organs of living things; and the physics/chemistry of these functions…
• 5.
  “Structure correlates tofunction” Always keep in mind that in plant anatomy, morphology & physiology…
• 6.
  • How canwater move from the ground all the way to the top of a 100 m tall redwood tree?
• 7.
  Plant Anatomy: Cells •Plant cells are basic building blocks • Can specialize in form and function • By working together, forming tissues, they can support each other and survive • Levels of organization atoms > molecules > cells > tissues > organs > whole plant > pop.
• 8.
  Plant Tissues Types Allplant organs (roots, stems, leaves) are composed of the same tissue types. There are three types of tissue: • 1. Dermal – outermost layer • 2. Vascular – conducting tissue, transport • 3. Ground – bulk of inner layers
• 9.
  1. Dermal tissue •Epidermis is the outermost layer of cells • Like the “skin” of animals • In stems and leaves, epidermis has cuticle, a waxy layer that prevents water loss. • Some have trichomes, hairs. • Root epidermis has root hairs, for water and nutrient absorption
• 10.
  2. Vascular tissue •Transports water and organic materials (sugars) throughout the plant • Xylem – transports water and dissolved ions from the root to the stem and leaves. • Phloem – carries dissolved sugars from leaves to rest of the plant
• 11.
  Xylem • Transports waterand dissolved minerals • Tracheids: long, thin tube like structures without perforations at the ends • Vessel elements: short, wide tubes perforated at the ends (together form a pipe, called vessel). • Both cells have pits (thin sections) on the walls Tracheids Vessel elements
• 12.
  Xylem cells • Xylemcells are dead! • They are hollow cells and consist only of cell wall
• 13.
  Phloem • Cells thattransport organic materials (sugars) • Phloem cells are ALIVE! (unlike xylem) • However, they lack nucleus and organelles
• 14.
  Phloem: transports sugars •Phloem composed of cells called sieve tube members (STM) • Companion cells join sieve tube members, are related, and help to load materials into STM • End walls of STM have large pores called sieve plates Sieve tube member Companion cells Sieve plates
• 15.
  3. Ground tissue •Makes up the bulk of plant organs. • Functions: Metabolism, storage and support. Root Stem Leaf
• 16.
  Plant Organs Organs: tissuesthat act together to serve a specific function • Roots • Stems • Leaves Dermal Vascular Ground Dermal Vascular Ground Dermal Vascular Ground
• 17.
  Functions of plantorgans: • ROOTS: Anchorage, water/nutrient absorption from soil, storage, water/nutrient transport • STEMS: Support, water/nutrient transport • LEAVES: Photosynthesis (food production)
• 18.
  ROOTS • ROOTS “thehidden half” • Functions of roots: • Ancorage • Absorption of water & dissolved minerals • Storage (surplus sugars, starch) • Conduction water/nutrients
• 19.
  Anatomy of aroot epidermis cortex vascular
• 20.
  Root Epidermis • Outermost,single layer of cells that: – Protects (from diseases) – Absorbs water and nutrients • ROOT HAIRS: tubular extensions of epidermal cells. • Increase surface area of root, for better water/nutrient absorption
• 21.
  Root Hairs: waterand mineral absorption Root hairs increase surface area for better absorption
• 22.
  Root Cortex • Storesstarch, sugars and other substances
• 23.
  Root Ground tissue •In roots, ground tissue (a.k.a. cortex) provides support, and often stores sugars and starch (for example: yams, sweet potato, etc.) Hey! I yam what I yam, man! You’re not a yam, you’re a sweetpotato! cortex
• 24.
  Root Cortex: Endodermis •Endodermis: the innermost layer of the cortex
• 25.
  Root cortex: Casparianstrip • The Casparian strip is a water-impermeable strip of waxy material found in the endodermis (innermost layer of the cortex). • The Casparian strip helps to control the uptake of minerals into the xylem: they have to go through the cytoplasm of the cell!
• 26.
  STEMS • Above-ground organs(usually) • Support leaves and fruits • Conduct water and sugars throughout plant (xylem and phloem)
• 27.
  Stem Anatomy • Bud– undeveloped shoot. • Node – Location of leaf or bud on stem. • Internode – Space between nodes. • Pith – Spongy tissue in the center of the stem. • Lenticel – Pore in the outer layer of the stem.
• 28.
  Stem
• 29.
  Stem Modifications • Tuber– underground stem with nodes • Rhizome – underground stem with buds • Stolon – aboveground stem with shoot buds • Bulb – underground stem with fleshy leaves • Corm – underground stem with papery leaves
• 30.
  Modified Stem Thorn Tendril Onion setRhizome
• 31.
  Modified Stem II AsparagusStolon
• 32.
  Stem anatomy • Dermal,ground and vascular tissues… pith cortex epidermis Vascular bundles
• 33.
  Types of Stems Monocotstem Dicot stem Root
• 34.
  Types of stems •Herbaceous vs. Woody stems
• 35.
  Tissues of stems •Epidermis (Dermal tissue type) • Provides protection • Has cuticle (wax) prevents water loss • Trichomes (hairs) for protection, to release scents, oils, etc.
• 36.
  Stem Vascular tissue •Vascular bundles – composed of both xylem and phloem • Xylem – Conducts water – Support • Phloem – Conducts food – Support Vascular cambium
• 37.
  Vascular cambium • Occursin woody stems • Vascular cambium located in the middle of the vascular bundle, between xylem and phloem
• 38.
  Vascular tissue: Trees •Vascular tissue is located on the outer layers of the tree. wood phloem xylem bark Vascular cambium
• 39.
  Girdling: cutting arounda tree • Damages the phloem and xylem, eventually killing the tree!
• 40.
  Vascular tissue formsrings in trees • Annual rings: xylem formed by the vascular cambium during one growing season • One ring = one year
• 41.
  History of thetree: annual rings 1489: Tree is planted by Native American 1492: Columbus lands in the Americas 1620: Pilgrims land in Plymouth, Mass. 1776: Declaration of US independence 1861: Start of Civil War 1969: Man lands on Moon 1917 & 1945: Tree Survives two World Wars 1971: Birth Year of the IDIOT who cut down this tree!!! Dendrochronology : tree time-keeping
• 42.
  Ground tissue: Cortex& pith • Stores food (e.g. potato) • Site of Photosynthesis (when green) • Support cells pith cortex
• 43.
  LEAVES: • ‘Photosynthetic factories’of the plant… • Function: Photosynthesis – food production for the whole plant • Blade: Flat expanded area • Petiole: stalk that connects leaf blade to stem, and transports materials BLADE
• 44.
  Leaf Anatomy • Leafanatomy is correlated to photosynthesis: Carbon dioxide + Water  sugars + oxygen dermal ground vascular dermal
• 45.
  Leaf epidermis • Istransparent – so that sun light can go through. • Waxy cuticle protects against drying out • Lower epidermis: stomata with guard cells – for gas exchange (CO2, H2O in; O2 out)
• 46.
  Leaf epidermis • Trichomes(give fuzzy texture) (“Panda plant”)
• 47.
  Leaf vascular tissue •VEINS  vascular tissue of leaves. • Veins are composed of xylem (water transport) phloem (food transport) and bundle sheaths, cells surrounding the xylem/phloem for strength & support
• 48.
  Leaf Mesophyll • Middleof the leaf (meso-phyll) • Composed of photosynthetic ground cells: • Palisade parenchyma (long columns below epidermis; have lots chloroplasts for photosynthesis) Spongy parenchyma (spherical cells) with air spaces around, (for gas exchange)
• 49.
  Plant Cells • Formedat meristems. – Mitosis in meristem produces new cells. • Two types of meristems. – Apical – produces primary growth, ex. tip of root or shoot. – Lateral – produces secondary growth, ex. cambium.
• 50.
  Apical Meristem
• 52.
  Flowers • Flower Parts-- Male – Stamen: Male part of the flower. – Filament: Stalk like in the stamen that holds up the anther – Anther: Sack-like structure that contains pollen.
• 53.
  Flowers • Flower Parts-- Male – Pollen grains are released from the anther that contains sperm. – Staminate: Flowers that have only male parts.
• 54.
  Flowers • Flower Parts– Female – Pistil: Female part of the flower – Stigma: Sticky part of the pistil that is receptive to pollen. – Style: Rod shaped middle part that has a swollen base (ovary) containing eggs
• 55.
  Flowers • Flower Parts– Neither male or female – Petals: colorful leaf-like structures which attract animals and insects. – Corolla: When all of the petals are fused together. – Sepals: Green leaves that protect the flower before it opens.
• 56.
  Flowers • Flower Parts– Niether male or female – Calyx: When all of the sepals are fused together.
• 57.
  Flowers • Flower Types: –Perfect Flower: Has both male and female parts. – Imperfect Flower: A flower that is missing either male or female parts. – Complete Flower: Flowers that have sepals, petals, pistils, and stamens.
• 58.
  Flowers • Flower Types: –Incomplete Flowers: When a flower is missing sepals, petals, pistils, or stamen. – Imperfect Flowers are always incomplete. Incomplete flowers may or may not be imperfect
• 59.
  From ovary tofruit • The ovary of the flower contains the ovules. • As fertilized ovules develop into seeds, the ovary wall develops into the fruit. • In science, the term “fruit” refers to a mature ovary that contains seeds.
• 60.
  Fruit anatomy
• 61.
  Types of dryfruits Legume (Bean pod) Capsule (Poppy) Achene (Sunflower) Silique (Money Plant) Follicle (Columbine) Nut (Hazelnut)
• 62.
  Types of fleshyfruits Drupe (Peach) Pome (Apple) Pepo (Cucumber) Aggregate (Strawberry) Multiple (Pineapple) Berry (Tomato)
• 63.
  Fruit dispersal • Theform of the fruit gives clues about its dispersal. • Small, dry fruits with “wings” or “parachutes” may be wind-dispersed. Fleshy fruits are often animal dispersed. Explosive fruits can fling seeds away. Floating fruits may be water dispersed.
• 64.
  How are thesefruits dispersed? Dandelion Coconut Maple Cocklebur Jewelweed
• 65.
  Thinking question: • Whymust fruits be dispersed away from the parent plant?
• 66.
  Seeds
• 67.
  Ovule to seed
• 68.
  Mature Seed
• 69.
  Seed anatomy
• 70.
  Seed dormancy • Seedscan remain dormant in the soil for long periods of time. Dormancy helps ensure that seeds only germinate when conditions are right. • When we weed or cultivate a bare patch of soil, the weeds that sprout up immediately usually come from the “seed bank” already in the soil.
• 71.
  Breaking dormancy • Seedsrequire moisture and the right temperature to germinate. • In addition, some seeds germinate only after certain environmental signals: – Drying – Temperature (period of cold or heat) – Disruption of the seed coat
• 72.
  Thinking question • Whatcould be the advantage of waiting for each of these signals to germinate? – Long period of cold – High heat of a forest fire – Drying out – Disruption of the seed coat.
• 73.
  Germination: monocot
• 74.
  Germination: dicot
• 75.
  • Is aseed alive? Is a fruit alive? Answer as completely as you can on your own paper. (Hang on to your paper until the end of class.) W O R K T O G E T H E R
• 76.
  Plant Life Cycle
• 77.
  Asexual Reproduction • Asexualreproduction is natural “cloning.” Parts of the plant, such as leaves or stems, produce roots and become an independent plant. • List some benefits and some drawbacks to asexual reproduction.
• 78.
  Sexual Reproduction • Sexualreproduction requires fusion of male cells in the pollen grain with female cells in the ovule. • List some advantages and drawbacks to sexual reproduction.
• 79.
  Terms to know: •Haploid: having a single set of chromosomes in each cell. • Diploid: having two sets of chromosomes in each cell. • Mitosis: cell division, which produces two genetically identical cells. • Meiosis: reduction division, which produces four haploid reproductive cells.
• 80.
  Animals vs. Plants PlantReproduction Animal Reproduction Life cycle Alternation of generations No alternation of generations Gametes Haploid gametes Haploid gametes Spores Haploid spores No spores Gametes made by Haploid gametophyte, by mitosis Diploid organism, by meiosis Spores made by Diploid sporophyte, by meiosis No spores
• 81.
  Alternation of Generations •Plants have a double life cycle with two distinct forms: – Sporophyte: diploid, produce haploid spores by meiosis. – Gametophyte: haploid, produce gametes by mitosis.
• 82.
  Non-flowering plants • Mosses,ferns, and related plants have motile, swimming sperm. • What kind of environmental conditions would be required for reproduction in these plants? • What kinds of limits does external reproduction impose on these plants?
• 83.
  Moss Life Cycle
• 84.
  Fern Life Cycle
• 85.
  Conifers • Conifers (alsonon-flowering plants) have reduced gametophytes. – Male gametophyte is contained in a dry pollen grain. – Female gametophyte is a few cells inside of the structures that become the seed.
• 86.
  Conifer life cycle
• 87.
  Conifer pollination • Conifersare wind-pollinated plants. • Chance allows some pollen to land on the scales of female cones. • Pollen germinates, grows a pollen tube into the egg to allow sperm to fertilize the egg. • What are some advantages and disadvantages to wind pollination?
• 88.
  Pollen go-betweens • Showyflowers are the result of selection for more efficient pollination strategies. • Flower parts are modified leaves. Those that were brightly colored attracted insects in search of pollen. • Why would insects search for pollen? What other rewards do flowers offer? • What are advantages and disadvantages to relying on insects as pollinators?
• 89.
  Flowers
• 90.
  Flower Parts
• 91.
  Imperfect flowers
• 92.
  Flowers • Sexual Reproductionin Plants: Two parents (meiosis) – #1 The stamen releases pollen. – #2 Pollen is carried by wind, gravity, animals, or insects to the stigma of another flower. (This is when pollination occurs) – #3 The pollen moves from the stigma down through in a pollen tube the style depositing sperm in the ovary.
• 93.
  Flowers • Sexual Reproductionin Plants: – #4 When the sperm has been deposited in the ovary fertilization has occurred. – #5 When the eggs have been fertilized, the ovary and surrounding tissue start to enlarge to become a fruit and the fertilized eggs become seeds.
• 94.
  Gametogenesis: Male
• 95.
  Gametogenesis: Female
• 96.
  Double Fertilization
• 97.
  Flower to Fruit
• 98.
  Ovule to Seed
• 99.
  Seed Anatomy
• 100.
  Growth Cycle • Annual– single season • Biennial – two seasons • Perennial – multiple seasons • Evergreen – leaves persist > 2 seasons • Deciduous – leaves die in cold or dry