Download Unit 5 - Section 13.2 2011 Vascular Plants

Grade 11 University Biology – Unit 5 Plants
Vascular Plant Body
Section 13.2 Pages 544-551
Vascular Plants have two systems.
 Shoot system (above ground)
 Consists of stems (structures, support,
transport, contain reproductive parts) and
leaves (photosynthesis)
 Root system (below ground)
 Anchors the plants
 Absorbs water and mineral nutrients
 Storage and transport
Three key differences from animal cells
 One large central vacuole (storage)
 Chloroplasts (photosynthesis)
 Cell wall (structure)
Plant Cells
Three types of plant cells (see Table 13.3 on Page 546)
 Parenchyma
 Flexible and thin-walled, spherical in shape, and cell wall flatten when packed together
 Wide range of functions including storage, photosynthesis, gas exchange and protection
 Collenchyma
 Long strings, elongated cells occurring in strands or cylinders
 Provide support to surrounding cells
 Cells walls expand as the cell grows – allows the plant to bend but not break
 Sclerenchyma
 Very thick secondary cell walls
 Contain lignin making cell wall tough and hard
 Die when completed growth and development
 Primary function is support
Plant Tissues
There are four main types of plant tissue
 Meristematic Tissue (see Figure 13.9 on
Page 547)
 Site of new cell production
 Undifferentiated embryonic plant
tissue
 Meristems – areas of rapidly
dividing cells
 PRIMARY GROWTH
 Most common meristems
are located at tips of roots
and stems – area called
APICAL MERISTEM – cause root and stems to grow longer
Tissues found along the stem and at the base of leaf blades are INTERCALARY
MERISTEM
 SECONDARY GROWTH
 Increases the circumference of roots and stems, strengthens the stem and
provide support for taller growth
 Occurs at LATERAL MERISTEMS (Two types – (1) Vascular cambium and (2)
Cork cambium (outer bark of trees, protective layer)
Dermal Tissue
 Outer covering of the plant
 EPIDERMIS is a single layer of dermal tissue – protective covering
 In woody plants, PERIDERM is secondary growth that forms cork
 Specialized Epidermal Tissue
 GUARD CELLS control the opening and closing of the stomata for gas exchange
 TRICHOMES are tiny growths on the surface of the epidermis
 Some cool plant and reduce evaporation
 Some secrete sticky or toxic substances that repel herbivores
 Some are spikes that physically puncture the skin of the herbivore
 ROOT HAIRS
 Tiny extensions of epidermal cells on roots
 Increase the surface area for absorption of water and nutrients
Ground Tissue
 Contain all three cell types
 Form most of plants internal and external material
 Wide range of functions including storage of starch, support, photosynthesis
Vascular Tissue
 Internal system of tubes the run lengthwise throughout stem to connect roots and leaves
 Two types
 XYLEM
 Transports water and minerals from roots to leaves
 In angiosperms, xylem has two cell types: (1)
tracheids and (2) vessel elements. When mature,
they die leaving tubes for transport (see Figure 13.12
on Page 549). Fluid between openings (called PITS)
 PHLOEM
 Transports nutrients (e.g., sugars) to growth areas or
to the roots for
storage
 Two types of cells: (1) sieve tube
elements and (2) companion cells
 Alive at maturity. Yet, sieve tube
element does not have a nucleus;
rather, companion cell (with
nucleus) carries out life functions to
support both cells. Sieve tube elements have plates at either end with
holes to allow for nutrient flow (see Figure 13.13 on Page 550)
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For additional readings, see http://www.biologyjunction.com/plant_structure_bi1.htm