Angiosperms Continued BIO 1500
Popular in Basic Life Diversity
Popular in Biology
This 10 page Class Notes was uploaded by Maggie Bruce on Wednesday September 28, 2016. The Class Notes belongs to BIO 1500 at Wayne State University taught by Thomas Dowling in Fall 2016. Since its upload, it has received 14 views. For similar materials see Basic Life Diversity in Biology at Wayne State University.
Reviews for Angiosperms Continued
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 09/28/16
Lateral meristems o Allows roots and shoots to increase in width o Called secondary growth o Vascular cambium – grows the xylem and phloem o Cork cambium – grows the outer bark Primary meristems o Apical meristems Protoderm Ground Procambium o Tissues Simple – one type of cells Complex – multiple types of cells Dermal Protection Complex tissue Ground Storage, support, photosynthesis Simple tissue Vascular Water and nutrient transport Complex tissue Ground tissue o Parenchyma Storage, secretion, photosynthesis, wound repair, reproduction Loosely packed Thin primary cell wall Alive at maturity Some have chloroplasts and are called chlorenchyma o Collenchyma Support Irregularly thickened primary cell wall Alive at maturity Celery strands o Sclerenchyma Dead at maturity Primary and secondary cell walls Fibers – provide strength Sclerids – mechanical protection Called stone cells Found in the pits of drupes Vascular tissue o Xylem Conducts water and dissolved minerals Only goes from roots to shoots Conducting cells - vessels and tracheids Sclerenchyma fibers Parenchyma cells Vessels Large Continuous tubes of dead vessel members Have perforations called pits Tracheids Small Complex tissue o Phloem Distributes sugars Conducting cells Monocots – sieve cells Eudicots – sieve tubes Parenchyma cells Monocots – albuminous cells Eudicots – companion cells Sclerenchyma fibers Complex tissue Dermal tissue o Epidermis o One cell layer thick o Protection o Leaves and stems are covered in a waxy cuticle to reduce water loss o Contains special cells Guard cells Open and close stomata Carbon dioxide enters, water and oxygen leave Trichomes Hair like growths Fuzzy appearance Protection from heat Deters herbivores (glandular bulbs release bad taste) Root hairs Tubular extensions Increases surface area Increases absorption efficiency Roots o Four regions Root cap Inside is columella cells Outside is root cap cells Protects the root apical meristem Detects gravity Lubricates root by producing mucigel Zone of cell division Cuboidal cells with small vacuoles and large nuclei Derived from the root apical meristem Zone of elongation Cells become longer and slightly wider Zone of maturation Cells have root hairs Eudicot root structure o Xylem is in the center o Epidermis is on the outer edge o Cortex in the middle is made of parenchyma cells and stores starches o Endodermis is below cortex (casparian strip) o Everything inside the endodermis is called the stele Pericycle Xylem (has four “arms”) Primary phloem Monocot root structure o Epidermis o Cortex o Endodermis o Stele Phloem Xylem arranged in a ring Pericycle Pith in the center Secondary growth in roots o Pericycle gives rise to lateral meristems o Vascular cambium divides to produce secondary xylem (wood) and secondary phloem (inner bark) o Cork cambium forms outer bark Casparian strip o Made of a fatty waterproof substance called suberin o Blocks the passage of water and minerals between cells o Only in dermal root cells Taproot o One large root with small lateral branch roots o In some eudicots o Food storage o Turnip, carrot Fibrous roots o Monocots o Many similarly sized roots o Grass Adventitious roots o Grow from somewhere that is not the primary root o Onions Modified roots o Prop roots Adventitious Keep plant upright Corn o Aerial roots Adventitious Get water from the air Orchids o Pnuemataphores Adventitious Facilitate oxygen uptake Mangrove tree o Water storage roots Store water Tropical plants o Food storage roots Store food Carrots o Haustoria Photosynthetic Penetrate host plant to steal nutrients Mistletoe o Contractile roots Pull plant into soil Lily bulbs o Buttress roots Adventitious Provide stability Trees Shoot apical meristems o Initiates stem tissues o Produces primordia o Develops into leaves, shoots, and flowers Leaf arrangement o Alternate – one leaf per node, most common o Opposite – two leaves per node o Whorled – three or more leaves per node Anatomy of a woody stem o Node – where leaf grows o Internode – area between node o Blade – big part of leaf o Peticle – leaf stem o Axil – angle between leaf in stem o Axillary bud – give rise to lateral branches o Terminal bud – makes the branch longer o Bud scales – protect terminal bud in winter o Terminal bud scale scars – where bud scales were attached, the number indicates the age of the branch o Leaf scar – where leaf was attached o Vascular bundle scar – where xylem and phloem entered leaf o Lenticels – small holes that help with gas exchange Herbaceous eudicot stem o Has cuticle o Then epidermis o Then collenchyma o Then cortex o Then vascular bundles Arranged in a circle Vascular cambium forms between xylem and phloem o Then pith Monocot stem o Vascular bundles are scattered o No vascular cambium Woody eudicot stem o Vascular cambium between xylem and phloem o Produces a lot of secondary xylem, wood, in annual rings o Heartwood is in the center Dark Old Not functional Support o Sapwood is around the outside Light New Functional o Secondary phloem, inner bark o Periderm, outer bark Phelloderm, cork cambium, cork cells Lenticels o Found in periderm of woody stems o And in pneumataphores o Gas exchange Modified stems o Bulbs Underground Swollen Leafy layers Onion o Corms Superficial bulbs No leafy layers o Rhizomes o Runners Horizontal stems Strawberries o Stolons Horizontal stems White potatoes o Tubers o Tendrils o Cladophylls Flattened photosynthetic stems Cactus Transport mechanisms o Water and minerals enter root o They move up the xylem o Water exits the stomata of leaves (transpiration) Transport between cells o Active movement of a substance against its concentration gradient ATP energy is needed o Passive Movement of a substance down its concentration gradient No energy is needed Simple diffusion Substances cross membrane without using membrane proteins Gasses, non-polar molecules Facilitated diffusion Substances cross membranes using membrane proteins Ions, sugars Isotonic solution o The solution has the same concentration of solutes as the cell o Water move in and out of the cell at the same rate o The cell is flaccid Hypertonic solution o The solution has a greater concentration of solutes as the cell o Water moves out of the cell at a faster rate than it moves in o Cell is in plasmolysis Hypotonic solution o The solution has a lower concentration of solutes than the cell o Water moves into the cell faster than it turns out o The cell is turgid o Plants was to be like this Root hair o Absorbs water by osmosis o Absorbs minerals by active transport Transport between cells o Apoplast route Through cell walls Has the least amount of control over what is transported o Symplast route Through the plasmodesmata o Transmembrane route Through the wall, membrane, cytoplasm, and vacuoles Has the most amount of control over what is transported Casparian strip o Allows the endodermal cells to control the water that goes to the xylem o Uses the apoplastic and symplastic routes Root pressure o Pushing force o Accumulation of ions o Occurs at night o Forces water through xylem o Causes guttation – loss in water through leaves, called dew Transpiration o Pulling force o Pulls water towards the leaves o Causes tension – negative pressure o Can pull water up to 490 ft in the air Water transport through xylem o Cohesion – attraction of water molecules to other water molecules o Adhesion – attraction of water molecules to xylem cells o Cavitation – vessels or tracheids are blocked by air bubbles, fixed by water moving through pits to unblocked xylem Guard cells o Open and close stomata o Open when turgid, uptake of chloride, potassium, and water, during the day o Closed when flaccid, at night Transpiration rate o When temperature increases, transpiration rate increases o When wind increases, transpiration rate increases o When humidity increases, transpiration rate decreases o When sunlight increases, transpiration rate increases o When carbon dioxide increases, transpiration rate decreases Drought adaptions o Dormancy o Loose leaves o Trichomes o Less stomata o Sunken stomata Flooding adaptions o Lenticels o Adventitious roots o Arenchyma Loose parenchymal tissue Oxygen is stored in the spaces High salinity adaptations o Pneumataphores use lenticels o Succulent leaves allow for photosynthesis underground and are full of water Phloem transport o Bidirectional o Moves from the photosynthetic source to the sink Pressure-flow theory o Sucrose is actively bonded to the companion cells at the source o Then it goes through the sieve tube and water rushes in o Turgor pressure increases o Sucrose is actively unloaded at the sink o Water leaves o Turgor pressure decreases Monocot leaves o No petioles o Stop growing at maturity Microphyll o Has on unbranched vein o Club mosses Megaphylly o Has many veins Parallel venation o Monocots o All vein are parallel Net venation o Eudicots o Veins branch out o Pinnate One main vein Small veins branch off o Palmate Several main veins Branch out from one point o Simple leaves Have an undivided blade o Compound leaves Have many small leaflets attached to one petiole o Twice compound Two sets of leaflets attached to one petiole Leaf cross section o Upper epidermis has trichomes o Lower epidermis has stomata o Mesophyll is the cells in the middle, chlorenchyma Palisade mesophyll is on top, tightly packed, only in eudicots Spongy mesophyll is on the bottom, loosely packed o Bundle sheath cells Protect the veins Involved in photosynthesis Parenchyma or sclerenchyma o Monocot leaf – evenly spaced veins o Eudicot leaf – cross sectioned and longitudinal veins can be seen Photosynthesis o 6CO + 6H O > C H O + 6O 2 2 6 12 6 2 o Occurs in chloroplasts o Chlorophylls – green pigments that capture energy from the sun Chloroplast o Stroma – semifluid in chloroplasts o Thylakoid – stacks o The stroma and thylakoid membrane are where photosynthesis occur Light dependent reactions o Require sunlight o Occurs in the thylakoid membrane o Photosystem On the membrane Made of proteins and chlorophylls o Produce oxygen, ATP and NADPH Calvin cycle o Occurs in the stroma o Requires ATP NADPH and carbon dioxide o Makes glucose and organic materials Why leaves change color o Chlorophyll is green o Carotenoids are red, yellow, and orange o In the spring there are more chlorophylls o In the fall chlorophyll breaks down so there are more carotenoids Why leaves fall off o Abscission – seasonal detachment o Auxin – hormone that inhibits abscission o Abscission layer – forms to separate petiole from stem when auxin levels decrease Modified leaves o Bracts Surround true petals Attract petals o Reproductive leaves Plantlets that are capable of growing into full plants Adventitious o Spines Reduce water loss Deter predators Non-photosynthetic o Window leaves Succulent, cone shaped Allows photosynthesis to occur underground o Shade leaves Large Less mesophyll Near the ground o Insectivorous leaves Trap insects Venus flytrap, sundew, pitcher plant Thorns and prickles are not modified leaves o Thorns are modified stems o Prickles are extensions of the cortex and epidermis Asexual reproduction o Produces genetically identical organisms o By mitosis o Vegetative reproduction New plants come from non-reproductive structures Suckers – roots, stems, and stumps Rhizomes Runners Stolons Adventitious plantlets