LAB: Plant Tissues and Roots Flashcards Preview

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Flashcards in LAB: Plant Tissues and Roots Deck (12)
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1

 3 Tissues Systems of Plants

  1. Dermal Tissue
  2. Vascular Tissue
  3. Ground Tissue

2

Dermal Tissue

  • Provides protective covering over plant parts
  • Epidermis and Periderm
  • Epidermis consists of epidermal cells and guard cells
    • Guard cells regulate the opening and closing of the stoma
  • Periderm tissue forms the outer bark of woody plants

3

Vascular Tissue

  • Xylem and Phloem: tissues designed for transport of materials throughout the plant body
    • Xylem - transports water and dissolved minerals from roots to plant body
    • Phloem - transports carb. products (sugar) of photosynthesis throughout the plant

4

Xylem (4 Cell Types)

  1. Vessel elements - non-living, barrel-like cells
  2. Tracheids - non-living tapered cells and are the water-conducting cells of xylem tissue
  3. Parenchyma cells - storage
  4. Fibers - function in support

5

​Phloem (4 Cell Types)

  1. Sieve tube members - most unique cells in nature, are long, enucleate (no nucleus) responsible for the transport of food
  2. Companion cells - smaller, nucleate cells that assist by loading and unloading sugars into and out of sieve tube members
  3. Parenchyma cells - storage
  4. Fibers - structural support

6

Ground Tissue

  • Parenchyma tissue - most abundant, storage
  • Collenchyma tissue - support
  • Sclerenchyma tissue - support and strongest (2 cell walls)
    • Sclereids - short cubical cells (ex. shells of nuts and pits of fruits)
    • Fibers - elongated, tapered cells often occurring in clumps in stems (wood, inner bark)

7

Overview of Plant Morphology

  • 3 basic organs
    • root
    • stem
    • leaves
  • divided into root system and shoot system

 

8

Zones of a Root Tip

  • Zone of cell division - area at the end of the root tip where cells are mitotically dividing. ​(apical meristem)
  • covered by a protective layer of parenchyma cells called the root cap
  • the region of elongation is an area where cells increase in volume, lengthening the root
  • region of differentiation, an are where cells mature into tissues and root hairs develop
  • root hairs  are extensions of epidermal cells designed to increase water absorption

9

Introduction to Roots

  • the first root that develops from the seed's embryo is called the primary root
  • additional roots are called secondary roots or lateral roots
  • roots that develop from leaves or stems are termed adventitious

 

  • Taproot system - large, central primary root with multiple smaller roots (eudicots)
  • Fibrous root system - primary root dies and adventitious roots arise from the stem (monocots)

10

Root modifications

 

  

  •   Prop roots - are aerial, adventitious roots that develop from the stem and will eventually penetrate the soil to offer additional support to tall plants
  • Storage roots - some taproots are enlarged to store additional water and nutrients (ex. carrots and sweet potatoes)

11

Root Tissues ​(monocot)

 

  • Epidermis - surrounds the cortex
  • Cortex - an area of loosely spaced parenchyma cells adapted for starch storage
  • Endodermis - interior to the cortex is a single layer of tightly packed cells
  • Stele - central core root, vascular cylinder
  • inside the endodermis is the pericycle, a layer of cells where secondary roots arise

 

  • in monocots, a pith is typically found in the center of the root
  • Surrounded by a ring of alternating bundles of xylem and phloem

12

Root tissues (eudicots)

  • center of stele is composed of  xlyem  cells rather than a pith
  •  Xylem cells arranged in the shape of a cross or star
  • Bundles of Phloem in between the arms of xylem tissues