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Figure 35.10 Review of General Plant Cell Structure

Figure 35.10 Review of General Plant Cell Structure. Shoot and Root Systems. Shoot system produces sugars by photosynthesis carries out reproduction. Shoot System. Root system anchors the plant penetrates the soil and absorbs water and minerals stores food. Root System.

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Figure 35.10 Review of General Plant Cell Structure

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  1. Figure 35.10 Review of General Plant Cell Structure

  2. Shoot and Root Systems • Shoot system • produces sugars by photosynthesis • carries out reproduction Shoot System • Root system • anchors the plant • penetrates the soil and absorbs water and minerals • stores food Root System

  3. Shoot and root systems are interdependent water & minerals sugar SHOOT SYSTEM ROOT SYSTEM

  4. Plant Tissue Systems EPIDERMIS • Ground tissue system • Vascular tissue system • Dermal tissue system VASCULAR TISSUES GROUND TISSUES SHOOT SYSTEM ROOT SYSTEM

  5. Meristems – Where Cells For New Organs 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

  6. Apical Meristems Lengthen shoots and roots activity at meristems new cells elongate and start to differentiate into primary tissues Cells that form at apical meristems: protoderm epidermis ground meristem  ground tissues procambium  primary vascular tissues

  7. Lateral Meristems Increases girth of older roots and stems Cylindrical arrays of cells vascular cambium secondary vascular tissues periderm cork cambium thickening

  8. Figure 35.7 The three tissue systems The Three Tissue Systems in Plants

  9. Simple Tissues Made up of only one type of cell Parenchyma Collenchyma Sclerenchyma

  10. Morphology of Three Simple Tissue Types parenchyma collenchyma sclerenchyma

  11. Figure 35.11 The three major categories of plant cells

  12. 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

  13. 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

  14. 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

  15. Complex Tissues Composed of a mix of cell types Xylem Phloem Epidermis

  16. Xylem • Conducts water and dissolved minerals • Conducting cells are dead and hollow at maturity vessel member tracheids

  17. Figure 35.8 Water-conducting cells of xylem

  18. Phloem: A Complex Vascular Tissue • Transports sugars • Main conducting cells are sieve-tube members • Companion cells assist in the loading of sugars sieve plate sieve-tube member companion cell

  19. Figure 35.9 Food-conducting cells of the phloem

  20. Figure 36.17 Pressure flow in a sieve tube

  21. Epidermis: A Complex Plant Tissue - Covers and protects plant surfaces - Secretes a waxy, waterproof cuticle • In plants with secondary growth,periderm replaces epidermis

  22. Monocots and Dicots – same tissues, different features 1 cotyledon 2 cotyledons 4 or 5 floral parts 3 floral parts Netlike veins Parallel veins 3 pores 1 pore Vascular bundles dispersed Vascular bundles in ring

  23. Stems – • organs consisting of an alternating • system of nodes, the points at which • leaves are attached, and internodes, • the stem segments between nodes. • the main functions of the stems include • conducting sugars and water and holding • leaves up into the sunlight

  24. Monocot and Dicot Stems (Two Divisions of Angiosperms) Dicot Stem Monocot Stem

  25. Bud = undeveloped shoot of meristematic tissue Leaves Internode spaces between leaf attachments Axillary bud at node (can form lateral shoots) Longitudinal section of terminal bud

  26. Shoot Development shoot apical meristem procambrium ground meristem protoderm cortex procambrium pith primary xylem primary phloem

  27. Internal Structure of a Dicot Stem - Outermost layer is epidermis - Cortex lies beneath epidermis - Ring of vascular bundles separates the cortex from the pith - The pith lies in the center of the stem

  28. Internal Structure of a Monocot Stem • The vascularbundles arescattered throughout the ground tissue • No division of ground tissue into cortex and pith

  29. 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

  30. Woody Stem periderm (consists of cork, cork cambium, and secondary cortex) secondary phloem SAPWOOD HEARTWOOD BARK vascular cambium

  31. Figure 35.23 Anatomy of a tree trunk

  32. 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

  33. 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

  34. 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

  35. Leaf Structure UPPER EPIDERMIS cuticle PALISADE MESOPHYLL xylem SPONGY MESOPHYLL phloem LOWER EPIDERMIS Stoma with guard cells CO2 one stoma O2

  36. Figure 35.19 Leaf anatomy

  37. Mesophyll:Photosynthetic Tissue • A type of parenchyma tissue • Cells have chloroplasts • Two layers in dicots • Palisade mesophyll • Spongy mesophyll

  38. Collenchyma Parenchyma

  39. Leaf Veins: Vascular Bundles • Xylem and phloem – often strengthened with fibers • In dicots, veins are netlike • In monocots, they are parallel

  40. 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 meristem root cap

  41. Fibrous Tap Root Systems Lateral Roots grow from the Tap Root

  42. Primary Growth of a Root

  43. epidermis endodermis cortex pericycle root hair phloem xylem

  44. cortex epidermis endodermis pericycle xylem phloem Cross Section of a Root

  45. 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

  46. Root Hairs and Lateral Roots • Both increase the surface 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 new lateral root

  47. Lateral Root Figure 35.16 The formation of lateral roots

  48. Figure 36.7 Lateral transport of minerals and water in roots

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