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Bio 100 Chapter 21
 

Bio 100 Chapter 21

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  • ชาติไทยคงมั่นทั่ว ธานินทร์ เพราะพระพ่อแห่งแผ่นดินคุ้มครองไทย ขอเทิดทูนพระองค์ พระพ่อแห่งแผ่นดิน เอกองค์สยามมินทร์ธิราชเจ้า ความสามัคคี ก่อให้เกิดความมีชัย จงรวมใจเทิดทูนพระราชวงศ์ จงทรงพระเจริญ ศูนย์ใจไทยทั่วหล้า ชาวประชาร่วมน้อมสดุดี

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    Bio 100 Chapter 21 Bio 100 Chapter 21 Presentation Transcript

    • Chapter 21 Plant Organization and Homeostasis Lecture OutlineCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
    • 21.1 Flowering plants typically have roots, stems, & leaves Most flowering plants possess a shoot system & a root system  Shoot system – stem, branches, leaves, & flowers  Root system – main root and its branches 21-2
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21.1A, pg. 432 terminal bud Organization of a plant body petiole axillary bud leaf blade stem node internode node vascular tissues (xylem and phloem) Shoot system Root system lateral branch root root hairs primary root root tip 21-3
    •  The Stem  4 main functions  Supports the leaves & flowers  Growth of stem  Transport of water & nutrients between leaves and roots  Food storage  Terminal bud in shoot tip  Produces new leaves and new axillary (lateral) buds  Axillary buds can produce new branches or flowers  Node is where a leaf or flower joins the stem  Internode is the region between the nodes 21-4
    • Figure 21.1B, pg. 433: Modified leaves adapt to a plant’s environment Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. stem leaves Spines are the leaves of a cactus 21-5 © Patti Murray/Animals Animals
    •  Leaves  Usually the primary organs of photosynthesis  Blade – wide portion of a foliage leaf  Petiole – stalk that attaches the blade to the stem  Examples of modified leaves: 21-6
    • Figure 21.1B Modified leaves adapt to a plant’s environment (Cont.) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. tendril Tendrils are modified leaves of a cucumber © Michael Gadomski/Photo Researchers, Inc 21-7
    • Figure 21.1B Modified leaves adapt to a plant’s environment (Cont.) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Leaves of a Venus flytrap capture insects 21-8 © Steven P. Lynch
    •  Roots  Main functions 1. Anchor plant in soil 2. Absorb water & minerals from soil 3. Produce hormones 4. Some also store food  Root hairs increase surface-to-volume ratio  Tap roots vs. fibrous roots Examples of each type of root system: 21-9
    • Figure 21.1C Taproot system (left) versus fibrous root system (right) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Taproot Fibroous root system (taproot): © Jonathan Buckley/Getty Images;; (fibrous root): © The McGraw-hill companies Inc./Evelyn Jo Johnson, photographer 21-10
    • 21.2 Flowering plants are either monocots or eudicots Monocots have one cotyledon  Root vascular tissue rings pith  Vascular bundles scattered in stem  Leaf veins are parallel  Flower parts in multiples of three Eudicots have two cotyledons  Root phloem between areas of xylem  Vascular bundles in a distinct ring  Leaf veins form a net pattern  Flower parts in multiples of four or five 21-11
    • Figure 21.2, pg. 434 Monocots & eudicots are structurally different Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Seed Root Stem Leaf Flower endosperm phloem pith axillary budMonocots xylem Root xylem and Vascular bundles Leaf veins form Flower parts in threes One cotyledon in seed phloem in a ring scattered in stem a parallel pattern and multiples of three xylem pith axillary bud Eudicots phloem Root phloem between Vascular bundles Leaf veins form Flower parts in fours or Two cotyledons in seed arms of xylem in a distinct ring a net pattern fives and their multiples 21-12
    • HOW BIOLOGY IMPACTS OUR LIVES 21.3 Monocots serve humans well Although the monocots are a small group compared to the eudicots, they have great importance Domestication of monocot plants included selective breeding in order to accumulate certain desirable traits in crops Corn is by far the most important crop plant in the United States Over 50% of the world’s people depend on rice for about 80% of their calorie requirements 21-13
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21A, pg. 435 grain head Monocot varietyRice plants, Oryza grain headWheat plants,Triticum (rice plants): © Corbis RF; (rice grain head): © Dex Image/Getty RF; (wheat): © Earl Roberge/Photo Researchers, Inc 21-14
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21A Monocot variety (Cont.) earCorn plants, Zea Barley (ear of corn): © Doug Wilson/Corbis; (corn plants): © Adam Hart-Davis/SPL/Photo Researchers, Inc.; (barley plants): © Sundell Larsen/Getty RF; (barley grains): © C. Sherburne/Photolink/Getty RF 21-15
    • 21.3 Plants have specialized cells & tissues Apical meristem  Located in the terminal bud of the shoot system and in the root tip  Daughter cells differentiate into 1 of 3 primary meristems 1. Epidermal tissue forms the outer protective covering of a plant 2. Ground tissue fills the interior of a plant and serves metabolic functions 3. Vascular tissue contains xylem and phloem 21-16
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21.1A, pg. 432 terminal bud Organization of a plant body petiole axillary bud leaf blade stem node internode node vascular tissues (xylem and phloem) Shoot system Root system lateral branch root root hairs primary root root tip 21-17
    •  Epidermal Tissue  Epidermis covers entire body of plant  Waxy cuticle minimizes water loss  Leaves contains stomata ringed by guard cells  Roots have root hairs  Epidermis is replaced by cork in tree trunk New cork cells are made by cork cambium 21-18
    • Figure 21.3A, pg. 436 Modifications of epidermal tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. guard cell chloroplasts corn seedling root hairs epidermal cell stoma nucleus elongating root tip a. Stoma of leaf b. Root hairs a: © J.R. Waaland/Biological Photo Service b: © Runk/Schoenberger/Grant Heilman Photography
    • Figure 21.3A Modifications of epidermal tissue (Cont.) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. lenticel periderm cork cambium corkc. Cork of older stem 20 µm c: © Kingsley Stern 21-20
    •  Ground Tissue  Bulk of stems, leaves, and roots  Contains three types of cells  Parenchyma cells – the least specialized of the cell types and are found in all the organs of a plant  Collenchyma cells have thicker primary walls than parenchyma cells  Provide structural support in nonwoody plants, especially in areas of elongation  Sclerenchyma cells have thick secondary cell walls impregnated with lignin  Makes plant cell walls tough and hard, in areas where growth has stopped elongation 21-21
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21.3B, pg. 436 Ground tissue cellsParenchyma cells with thin walls 50 µmCollenchyma cells 50 µm Sclerenchyma cells 50 µmwith thicker walls with very thick walls 21-22 (all): © Biophoto Associates/Photo Researchers, Inc
    •  Vascular Tissue  Xylem  Transports water and minerals from roots to leaves  Contains vessel elements (thicker) & tracheids (thinner)  Phloem  Transports sugar, in the form of sucrose, and other organic compounds, such as hormones, from the leaves to the roots  Sieve-tube members – conducting cells of phloem are arranged to form a continuous sieve tube  Companion cells – nucleated cells 21-23
    • Figure 21.3C, pg. 437 Xylem structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. xylem parenchyma vessel cell element tracheid tracheids pitted end wall walls vessel element pitsa. Xylem micrograph 50 µm c.Tracheids b.Two types of vessels (Left): © J.R. Waaland/Biological Photo Service 21-24
    • Figure 21.3D, pg. 437 Phloem structure Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. sieve plate sieve-tube member sieve plate nucleus sieve-tube member companion cell companion cell phloem parenchyma cell 20 µmPhloem micrograph Sieve-tube member and companion cells (Left): © George Wilder/Visuals Unlimited 21-25
    • 21.4 The three types of plant tissues are present in each organ Leaf  Upper and lower epidermis has an outer, waxy cuticle, which prevents water loss  Stomata located in lower epidermis  Interior of a leaf is made of mesophyll,  Ground tissue composed of parenchyma cells  Contain chloroplasts and carry on photosynthesis  Palisade (tightly packed, elongated cells) vs spongy mesophyll (irregular cells bounded by air spaces right next to the stomata)  Leaf veins branch and terminate in the mesophyll 21-26
    • Xylem transports cuticle water and minerals. upperPhloem transports sugar. epidermis mesophyll lower xylem epidermis stoma leaf vein phloem guard cell a. Leaf
    •  Stem  Herbaceous plants have “nonwoody” stems  Ground tissue consists of cortex and central pith  Vascular bundles  Ring in eudicot  Scattered in monocot  Vascular tissue supports shoot system and transport food and water 21-28
    • Figure 21.4B Internal structure of the leaf, stem, and root Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. vascular vascular epidermis bundle bundle epidermis cortex cortex pithTissue Types 100 µm epidermal ground b. Eudicot stem c. Monocot stem vascular b: © Ed Reschke; c: © CABISCO/Phototake; 21-29
    •  Root  Epidermis usually consists of only a single layer of cells and many epidermal cells have root hairs  Large, thin-walled parenchyma cells make up the cortex, the layer of ground tissue cells located beneath the epidermis  Cells contain starch granules, and the cortex functions in food storage 21-30
    • epidermis vascular cylinder endodermis cortexTissue Types phloem epidermal ground xylem 50 µm vascular All tissues d. Eudicot root Vascular cylinder
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21.4A , pg. 438epidermaltissue Arrangement of plantvascular tissues in the organs oftissue ground eudicots tissue Leaf epidermal tissue vascular tissue ground tissue Stem vascular ground tissue tissue epidermal tissue Root 21-32
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 21.4B Internal Xylem transports water and minerals. cuticle structure of the leaf, stem, and root upper Phloem transports sugar. epidermis mesophyll lower xylem epidermis stoma leaf vein phloem guard cell a. Leaf vascular vascular epidermis bundle bundle epidermis cortex cortex epidermal tissue pith 100 µm ground tissue b. Eudicot stem c. Monocot stem vascular tissueshoot systemroot system epidermis vascular cylinder endodermis cortex Tissue Types phloem epidermal ground xylem 50 µm vascular All tissues d. Eudicot root Vascular cylinder 21-33 b: © Ed Reschke; c: © CABISCO/Phototake; d: © CABISCO/Phototake
    • 21.5 Primary growth lengthensthe root & shoot systems Primary growth  Causes a plant to grow lengthwise  Centered in the apex (tip) of the shoot and of the root  Meristem is a region of actively dividing cells 21-34
    •  Root System  Zone of cell division  Protected by the root cap  Contains the root apical meristem 21-35
    •  Root System  Zone of elongation  Region where the root increases in length due to elongation of cells  Cells lengthen but are not fully specialized  Zone of maturation  Region that does contain fully differentiated cells  Recognized by root hairs 21-36
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.epidermiscortexendodermispericyclephloemxylem root hair Figure 21.5A , pg. 440 Cells within a eudicot root tip Zone of maturationZone ofelongation Vascular cylinderZone of procambiumcell division ground meristem protoderm Root apical meristem protected by root cap Root cap root cap a. b. 21-37 (Right): Courtesy Ray F. Evert/University of Wisconsin Madison
    •  Shoot System  Shoot apical meristem produces everything  Leaves, axillary buds (can develop into stems or flowers), additional stem and sometimes flowers  Gives rise to the same primary meristems as in the root  Protoderm → becomes epidermis of stems and leaves  Ground mersitem → become cortex, pith, and mesophyll  Procambium → vascular tissue (xylem and phloem)  Vascular cambium responsible for secondary growth (growing wider) 21-38
    • Figure 21.5B, pg. 441 Shoot apical meristem Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. leaf primordium shoot apical meristem protoderm ground meristem procambium epidermis internode cortex auxillary bud vascular cambium xylem phloem © J.R. Waaland/Biological Photo Service 21-39
    •  Shoot System – Ex: Winter Twig Terminal bud contains the apical meristem and leaf primordia of the shoot tip protected by terminal bud scales Leaf scars and vascular bundle scars mark spot of abscission (dropoff) Determine age of a stem by counting terminal bud scale scars because there is one for each year’s growth 21-40
    • Figure 21.5C, pg. 441 Winter twig showing stem organization Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. vascular bundle terminal bud scars scales Twig during winter leaf scar terminal bud axillary bud terminal bud scale scar Twig during spring 21-41
    • Secondary Plant Growth Secondary growth occurs only in woody plants Increases the girth (or width) of trunks, stems, branches, and roots Occurs due to the growth of lateral meristems: vascular cambium and cork cambium Woody stem has 3 distinct areas  Bark, wood, and pith  Wood is actually secondary xylem that builds up year after year 21-42
    • Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 primary xylem secondary xylem Figure 21.6A, pg. 442 vascular cambium secondary phloem In a tree, vascular pith primary phloem primary xylem cork cambium cork cambium produces primary phloem cortex secondary xylem and epidermis Vascular cambium: phloem each year Lateral meristem that will produce secondary xylem and secondary phloem in each succeeding year. 2 primary xylem secondary xylem secondary phloem primary phloem 3 Bark: Includes periderm and also phloem Wood: Increases each year; includes annual rings of xylem Pith: Parenchyma cells that have a storage function; becomes squeezed out by heartwood xylem ray phloem ray cork cambium cork lenticel 21-43
    •  Bark  Contains periderm and phloem  Periderm is a secondary growth tissue that contains cork and cork cambium  Cork cambium lies beneath the epidermis, but later it is part of the periderm, which replaces epidermis  Cork cambium divides and produces the cork cells that disrupt and replace the epidermis 21-44
    • Figure 21.6B, pg. 442 Heartwood has no transport function and serves as a depository for various substances such as resins and tannin. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. heartwood Wood sapwood vascular cambium phloem Bark cork 21-45
    • 21.7 Leaves are organized to carry onphotosynthesis Functions of a foliage leaf  Carry on photosynthesis, regulate water loss, and be protective against parasites and predators Epidermal tissue on upper and lower surfaces  Waxy cuticle to prevent water loss  Stomata all CO2 gain and water loss 21-46
    •  Mesophyll  Elongated cells of the palisade mesophyll carry on most of the photosynthesis  Loosely packed spongy mesophyll increases the amount of surface area for CO2 gain and water loss Leaf veins  Bring water and minerals to leaves and distribute products of photosynthesis to other parts of plant  Bundle sheaths – layers of cells surrounding vascular tissue 21-47
    • Figure 21.7, pg. 444 Leaf anatomy Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. blade trihome axillary bud petiole cuticle Water and minerals upper epidermis enter leaf through xylem. palisade mesophyll Sugar exits leaf bundle sheath cell air space through phloem. spongy mesophyll lower epidermis cuticle leaf vein stoma central vacuole upper epidermis nucleus chloroplast chloroplast epidermal cell palisade mesophyll O2 and H O2 exit leaf through stoma. leaf vein nucleus guard cell spongy CO2 enters leaf mesophyll through stoma.mitochondrion lower stoma epidermis Leaf cell Stoma and guard cells SEM of leaf 100 µm © Jeremy Burgess/SPL/Photo Researchers, Inc 21-48
    • 21.8 Various mechanisms help plants maintain homeostasis Anatomy of plants allows photosynthesis to occur  Vascular tissue (xylem and phloem) brings water and minerals  CO2 from stomata  Exposure to solar energy Products of photosynthesis maintains homeostasis (constancy of the internal environment) Epidermis protects plants from invasion Closing stomata prevents water loss 21-49
    • Figure 21.8A, pg. 445 The organization of plants is conducive to maintaining homeostasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. leaf palisade upper vein mesophyll epidermis vascular tissues stoma lower spongy epidermis mesophyll (Middle): Courtesy Ray F. Evert/University of Wisconsin Madison 21-50
    • Figure 21.8B Stomata open (left) and close (right) according to water availability Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stoma open 25 µm Stoma closed 25 µm © jeremy Burgess/SPL/Photo Researchers, Inc. 21-51
    •  Phloem transport  Source (where there are abundant sugar or carbohydrates) to sink (where extra sugar or carbohydrates are needed) transport Plant hormones  Highly specific chemical signals between plant parts and cells  Tropism is a growth response toward or away from a particular stimulus Examples: if in dark place, grow towards light Defense Mechanisms  Cuticle, epidermal projections, chemical toxins Mutualistic relationship of plant roots and fungi  Increase surface area by which roots absorb water and 21-52 minerals from soil, give fungi carbohydrates
    • Figure 21.8C, pg. 446 Homeostatic mechanisms Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. mature leaf sugar sun a. Phloem transports sugar to areas of need. immature leaf b. Hormones cause plants to bend toward the light. pathogenic microbial attackd. Plants practice local cell death c. Plant roots associate as a defense against attack. with fungi to acquire minerals. dead cell living cell plant cells 21-53 C: © D. H. Marx/Visuals Unlimited
    • Connecting the Concepts: Chapter 21 Flowering plants are adapted to living on land Prevention of water loss is critical for land plants  Stomata and cork On land, plants had to evolve a way to oppose the force of gravity  Sclerenchyma cells, tracheids, and vessel elements.  Secondary growth Means of water uptake and transport  Root hairs, xylem 21-54