plant morphological lab activities ch 091129203156-phpapp01

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plant morphological lab activities ch 091129203156-phpapp01

  1. 1. March 28, 2005 Plant Tissues Chapter 26 Jin Hoe Huh
  2. 2. Angiosperms – flowering plants• The angiosperms are seed-bearing vascular plants• In terms of distribution and diversity, they are the most successful plants on Earth• The structure and function of this plant group help explain its success
  3. 3. FloweringPlant Life Double fertilization Diploid Meiosis Meiosis Cycle Haploid Mitosis without microspores pollination cytoplasmic division Two sperms enter ovule Female gametophyte
  4. 4. Plant Life Histories• Annuals complete life cycle in one growing season• Biennials live for two seasons; flowers form in second season• Perennials grow and produce seeds year after year
  5. 5. Shoot and RootSystemsShoot system- produces sugars by Shootphotosynthesis System- carries out reproductionRoot system- anchors the plant- penetrates the soil and Rootabsorbs water and minerals System- stores food
  6. 6. Shoot and rootsystems areinterdependent water & sugar minerals SHOOT SYSTEM ROOT SYSTEM
  7. 7. Plant Tissue Systems EPIDERMIS• Ground tissue VASCULAR TISSUES system• Vascular tissue GROUND TISSUES system SHOOT SYSTEM• Dermal tissue ROOT SYSTEM system
  8. 8. Meristems – Where Tissues Originate• Regions where cell divisions produce plant growth• Apical meristems – Lengthen stems and roots – Responsible for primary growth• Lateral meristems – Increase width of stems – Responsible for secondary growth
  9. 9. Apical MeristemsLengthen shoots and roots: activity at meristemsSAM and RAMCells that form at apical new cells elongatemeristems: and start to differentiateprotoderm  epidermis into primary tissuesground meristem  groundtissuesprocambium  primaryvascular tissues
  10. 10. Lateral MeristemsIncreases girth of older roots and stemsCylindrical arrays of cells vascular cambium  secondary vascular tissues periderm  cork cambium thickening
  11. 11. Simple TissuesMade up of only one type of cell Parenchyma Collenchyma Sclerenchyma
  12. 12. Morphology of three simple tissue typesparenchyma collenchyma sclerenchyma
  13. 13. Parenchyma: A Simple Tissue• Comprises most of a plant’s soft primary growth• Cells are pliable, thin walled, many sided• Cells remain alive at maturity and retain capacity to divide• Mesophyll is a type of parenchyma that contains chloroplasts
  14. 14. Collenchyma: A Simple Tissue• Specialized for support for primary tissues• Cells are elongated, with walls (especially corners) thickened with pectin• Makes stems strong but pliable• Cells are alive at maturity
  15. 15. Sclerenchyma: A Simple Tissue • Supports mature plant parts • Protects many seeds • Cells have thick, lignified walls and are dead at maturity • Two types: – Fibers: Long, tapered cells – Sclereids: Stubbier cells
  16. 16. Complex TissuesComposed of a mix of cell types Xylem Phloem Epidermis
  17. 17. Xylem• Conducts water and dissolved minerals• Conducting cells are dead and hollow at maturity vessel member tracheids
  18. 18. Phloem: A Complex Vascular Tissue sieve plate• Transports sugars• Main conducting cells are sieve- tube members sieve-tube• Companion cells member companion assist in the cell loading of sugars
  19. 19. Epidermis: A Complex Plant Tissue- Covers and protects plantsurfaces- Secretes a waxy,waterproof cuticle- In plants with secondarygrowth, periderm replacesepidermis
  20. 20. Monocots and Dicots – same tissues, different features 1 cotyledon 2 cotyledons 3 floral 4 or 5 floral parts parts Netlike veins Parallel veins 1 pore 3 pores Vascular Vascular bundles bundles in ring dispersed
  21. 21. shoot apical meristem Shoot protoderm procambrium ground meristemDevelopment cortex procambrium pith primary xylem primary phloem
  22. 22. Bud = undeveloped shoot of meristematic tissue Leaves InternodeAxillary bud at node Longitudinal section of terminal bud
  23. 23. Roots also have meristems
  24. 24. Internal Structure of a Dicot Stem- Outermost layer is epidermis- Cortex lies beneath epidermis- Ring of vascular bundlesseparates the cortex from the pith- The pith lies in the center of thestem
  25. 25. InternalStructure • The vascular bundles of a are distributedMonocot throughout the ground tissue Stem • No division of ground tissue into cortex and pith
  26. 26. Dicots Monocots Ground tissue system Dermal tissue system Vascular tissue systemDicots and Monocots have different stem and root anatomies
  27. 27. Leaf Gross Structure DICOT MONOCOT petiole axillary bud blade node sheath blade node
  28. 28. Adapted for Photosynthesis• Leaves are usually thin – High surface area-to-volume ratio – Promotes diffusion of carbon dioxide in, oxygen out• Leaves are arranged to capture sunlight – Are held perpendicular to rays of sun – Arrange so they don’t shade one another
  29. 29. Leaf Structure UPPER cuticle EPIDERMIS PALISADE MESOPHYLLxylem SPONGY MESOPHYLLphloem LOWER EPIDERMIS O2 CO2 one stoma
  30. 30. Mesophyll:Photosynthetic Tissue• A type of parenchyma tissue• Cells have chloroplasts• Two layers in dicots – Palisade mesophyll – Spongy mesophyll
  31. 31. Collenchyma Parenchyma
  32. 32. Leaf Veins: Vascular Bundles• Xylem and phloem – often strengthened with fibers• In dicots, veins are netlike• In monocots, they are parallel
  33. 33. Root Systems
  34. 34. Root Structure• Root cap covers tip• Apical meristem produces the cap• Cell divisions at the apical meristem cause the root to lengthen• Farther up, cells differentiate and mature root apical root cap meristem
  35. 35. Internal Structure of a Root• Outermost layer is epidermis• Root cortex is beneath the epidermis• Endodermis, then pericycle surround the vascular cylinder• In some plants, there is a central pith
  36. 36. epidermisendodermis cortexpericycle root hair phloem xylem
  37. 37. Root Hairs and Lateral Roots new• Both increase the surface lateral root area of a root system• Root hairs are tiny extensions of epidermal cells• Lateral roots arise from the pericycle and must push through the cortex and epidermis to reach the soil
  38. 38. Secondary Growth• Occurs in perennials• A ring of vascular cambium produces secondary xylem and phloem• Wood is the accumulation of these secondary tissues, especially xylem
  39. 39. Secondary Growth
  40. 40. Woody Stemperiderm (consists of secondary HEARTWOOD SAPWOODcork, cork cambium, phloemand secondary cortex) BARKvascular cambium
  41. 41. Annual Rings• Concentric rings of secondary xylem• Alternating bands of early and late wood• Early wood – Xylem cells with large diameter, thin walls• Late wood – Xylem cells with smaller diameter, thicker walls
  42. 42. Types of Wood• Hardwood (oak, hickory) – Dicot wood – Xylem composed of vessels, tracheids, and fibers• Softwood (pine, redwood) – Gymnosperm wood – Xylem composed mostly of tracheids – Grows more quickly

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