Plant Tissues: Overview

1
Plant Tissues Overview

• Meristems, Simple Tissues, Complex Tissues

• Many of the figures found in this presentation
  are from the internet site http//botit.botany.wis
  c.edu/images/130/ and a CD entitled Plant
  Anatomy by Richard Crang Andrey Vassilyev
  published by McGraw Hill.

2

• I. Meristematic Tissue
• Origin Promeristem, Meristem Primer,
  Meristem Sekunder (cambium)
• Location apical, intercalar, lateral
• Permanent Tissue
• Epidermis silica cell, stomata, trichomata,
  spine, velamen, fan cells.
• Parenchyme assimilation, storage, water,
  vascular, aerenchyme, wound covering.
• Supporting collenchyme,sclerenchyme
  (schlerenchyme fiber, sclereid)
• Vascular xylem (tracheid, vessel element),
  phloem (sieve tube element, companion cells)
• Cork feloderm, felem

3
Specialized Tissues in Plants

• Roots
• Absorbs water and nutrients
• Anchor plant to the ground
• Hold soil in place and prevent erosion
• Protect from soil bacteria
• Transport water and nutrients
• Provide upright support

4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
Specialized Tissues in Plants

• Stems
• Support for the plant body
• Carries nutrients throughout plant
• Defense system to protect against predators and
  infection
• Few millimeters to 100 meters

8
Specialized Tissues in Plants

• Leaves
• Main photosynthetic systems
• Suseptable to extreme drying
• Sight of oxygen/carbon dioxide intake and release

9
MERISTEMATIC TISSUE

• The cells of meristematic tissue are similar in
  structure have thin cellulose cell walls.
• The meristematic cells may be spherical,oval,polyg
  onal or rectangular in shape.
• The meristematic cells contain few vacuoles
• Cells of meristems divide continuously
• Occurrence-Meristematic tissues are growth
  tissues are found in those regions of the plant
  that grow. According to their position in the
  plant, meristems are apical, lateral
  intercalary.
• Function-the main function of meristematic
  tissue is to continuously form a number of new
  cells.

10
(No Transcript)
11
Intercalary Meristem
12
Meristematic tissues localized regions of cell
division

• Apical meristems-these are situated at the
  growing tip of the stems roots. At shoot apex
  root apex. It brings about the elongation of the
  root stem. It results in increase in the height
  of the plant, which is called primary growth.
• Lateral meristems-these are found beneath the
  bark (cork cambium) in vascular bundles of
  dicot roots stems(cambium).They occur in thin
  layers. Cambium is the region which is
  responsible for growth in thickness. It causes
  the organ(stem or root) to increase in diameter .
  This is called secondary growth.
• Intercalary meristems-they are located at the
  base of leaves or internode,e.g., Stem of grasses
  other monocots.

13
Root Apical Meristem

1. Root cap initials
2. Protoderm
3. Ground meristem
4. Procambium
5. Root cap

14
Lateral Meristems secondary growth in woody
plants
Basswood stem in cross section 1, 2, 3 year
old stems
Basswood root in cross section
15
PARENCHYMA

• Parenchyma cells are oval,round,polygonal or
  elongated in shape. The cell wall is thin
  encloses a dense cytoplasm which contains a small
  nucleus surrounds a large central vacuole.
• Occurrence-the parenchyma is widely distributed
  in stem,roots,
• Functions-
• Parenchyma maintain the shape firmness of the
  plant due to its turgid cells. The main function
  of parenchyma is to store assimilate food.
  Parenchyma serves as food storage tissue .
• Transport of materials occurs through cells or
  cell walls of parenchyma cells. Parenchyma cells
  are metabolically active their intercellular air
  spaces allow gaseous exchange.

16
Isodiametric Parenchyma Cell containing
Chromoplasts Each red dot is a Chromoplast that
Contains Carotenoids.
17
Elongate Palisade Parenchyma with Chloroplasts
18
Parenchyma from Potato with large Amyloplasts
19
Parenchyma Cells containing Amyloplasts.
20
Shoot Apical Meristem
21
PERMANENT TISSUE

• These tissues derived from the meristematic
  tissues but their cells have lost the power of
  division have attained their definite forms.
  Permanent tissues are classified into two-simple
  complex.
• Permanent tissue-these tissues are composed of
  cells which are structurally functionally
  similar. They are
• Epidermis
• Connective
• Vascular

22
Parenchyma
23
Surface View of  Epidermis from a Leaf Note the
undulating Epidermal Cells plus the Stomata (S)
and Trichomes (T).
24
(No Transcript)
25
COLLENCHYMA

• It shows many of the features of parenchyma but
  is characterized by the deposition of extra
  cellulose at the corners of the cells. In
  collenchyme ,intercellular spaces are generally
  absent. Collenchyme cells are elongated in shape.
  They often contain a few chloroplasts.
• Occurrence-the cells of collenchyma are located
  below the epidermis of dicotyledon stem
  petiole. Collenchyma is absent in monocot
  stems,roots leaves.
• Functions- collenchyma is a mechanical tissueit
  provides mechanical support elasticity.

26
SCELERENCHYMA

• Composed of dead cells and sclerenchyma are
  greatly thickened with deposition of lignin. The
  cells of sclerenchyma are closely packed without
  intercellular spaces.
• Found in stems,roots,veins of leaves.
• Functions-the sclerenchyma is mainly mechanical
  protective in function. It gives
  strenght,rigidity,flexibility elasticity to the
  plant body ,thus,enables it to withstand various
  strains.

27
XYLEM

• Nature-xylem is a vascularXylem is composed of
  cells of four different types
• tracheids and vessels element (bounded by thick
  lignified. Vessels are very long tube-like
  structures formed by a row of cells placed end to
  end. They conduct water).
• Functions-
• The main function of xylem is to carry water
  minerals salts upward from the root to different
  parts of shoots.
• Since walls of tracheids,vessels of xylem are
  lignified, they give mechanical strength to the
  plant body.

28
PHLOEM

• Nature-Phloem is composed of following two types
  1.sieve tubes2.companion cells
• Functions-phloem transport photosynthetically
  prepared food materials from the leaves to the
  storage organs later from storage organs to the
  growing regions of the plant body.

29
Collenchyma
30
Sclerenchyma
SCLERIDS
FIBERS
Right-hand illustration modified from Weier,
Stocking Barbour, 1974, Botany An Introduction
to Plant Biology, 5th Ed.
31
Epidermis stoma, trichomes, root hairs
http//www.ucd.ie/botany/Steer/hair/roothairs.html
32
Xylem
33
Phloem
34
Vascular Bundles with xylem phloem
Maize or Corn vein in cross section
Alfalfa vein in cross section
35
Periderm cork parenchyma
TWIG WITH LENTICELS
36
Secretory Structures

• nectar (flowers) from nectaries
• oils (peanuts, oranges, citrus) from accumulation
  of glands and elaioplasts.
• resins (conifers) from resin canals
• lacticifers (e.g., latex - milkweed, rubber
  plants, opium poppy)
• hydathodes (openings for secretion of water)
• digestive glands of carnivorous plants (enzymes)
• salt glands that shed salt (especial in plants
  adapted to environments laden with salt).