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ANATOMYANATOMY
Refers to the internal structure of plants.
The plant body is made up of groups of
identical as well as complex cells.
Anatomical Characteristics Assist Us in Understanding:
1. The process of photosynthesis, absorption and movement of water, as well as the translocation of food.
2. The success and failures of horticultural practices such as pruning, grafting and other forms of vegetative propagation.
3. Plant Pathology, particularly the anatomical structure of plant parts that are attacked thus giving further insight on the parasitic effect.
4. Taxonomy.
Main TopicsMain Topics
A. Types of Cells and Tissues
B. Primary and Secondary Growth :root, stem, leaf, flower, fruit and
seed
TISSUESTISSUES
Meristematic Tissues
- apical meristem
- lateral meristems
- intercalary meristem
Non Meristematic Tissues Simple tissues - parenchyma - collenchyma - sclerenchyma
Complex tissues - xylem - phloem - epidermis - periderm - secretory cells and tissues
Tissue: A group of cells that perform similar function(s)
Meristematic tissue
- Consists of newly formed cells, small sized, with thin cell wall and dense protoplasm, box shaped and having six surfaces, a large nucleus and small vacuoles
- Cells are always actively dividing
- When mature, the cell shape differs according to the cell function, while the vacuoles increase in size
Meristematic cells
Apical meristem- found at the tip of shoots and roots- The plant lengthens as the apical
meristem produces new cells
** Gives rise to 3 primary meristems: protoderm, ground meristem, and procambium (which forms the xylem dan phloem).
Primary meristem produces the primary tissues primary growth
Shoot apical meristem
Primary meristems in a shoot apex
Root apical meristem
Lateral meristems
- Vascular cambium and cork cambium
- Produce tissues that increase the girth of stem
and roots
- Vascular cambium : a thin cylinder in stem and
root of annuals and perennials
- Cork cambium : a thin cylinder in stem and root of
woody plants, found outside the vascular cambium
and within the bark of plants
- Tissues produced from both the vascular cambium
and cork cambium are secondary tissues formed
after the maturation of the primary tissues
secondary growth
Lateral meristem
Intercalary meristem
- Grass species (Graminae) do not possess vascular
cambium and cork cambium, instead they have
apical meristem and intercalary meristem
- Intercalary meristems are found close to the
node region, producing primary tissues that result
in the increase in length (elongation) of stems.
Intercalary meristem
NON-MERISTEMATIC (SIMPLE TISSUE)
1. Parenchyma tissue
consists of
parenchyma cells,
the most abundant
tissue in the plant
body, found almost
in all important parts
of flowering plants.
Parenchyma cells:
Living cells, almost round in shape when first formed
The cell surface becomes even and smooth
when the thin cell wall touches each other
Can form diverse shapes and sizes, mostly
having 14 surfaces
Contains a large vacuole and perhaps starch,
oil, tannin, crystals and various forms of
secretion
Perform the basic metabolic functions of cells:
respiration, photosynthesis, storage and
secretion
Having intercellular spaces
*parenchyma cells with large
intercellular spaces are termed
arenchymas
*parenchyma cells that contain abundant
chloroplasts are termed chlorenchymas
*Transfer cells - parenchyma cells with
elongated plasmalema, large cell
surface, facilitate short distance
transport between cells
Parenchyma
Elodea leaf showing chlorenchymas
Parenchyma cells
ARENCHYMA
2. Collenchyma tissue
- consists of living cells, the shape is more elongated
than broad
- with rather thick cell wall
- the cell wall is very flexible but strong – functions to
give support to stem, leaves and flower parts
- collenchyma cells originate from parenchyma cells
- found below the epidermis, close to the leaf midribs
and veins, or near vascular bundles
Stem cross section of Sambucus spp.
Collenchyma tissue
Collenchyma in leaf midrib
3. Sclerenchyma tissue
- cells possess a thick and strong
secondary wall composed mainly of lignin (a polymer)
- cells are dead (lacking a living protoplast) when mature
- function to provide support and sometimes protection to the plant
- There are two forms of sclerenchyma cells:
sclereid and fibre
Sclerenchyma
fibre
Sclereids
- originate from parenchyma cells
- cell shape : width equal length
(isodiametric)
- spread randomly within the plant tissue and
exists in various forms or shapes:
brachysclereid macrosclereid osteosclereid astrosclereid trichosclerid
- a gritty texture that
occurs in pears is due
to the presence of
sclereids
- sclereids are
sometimes found in
leaves and in seed
coat (particularly the
testa)
Sclereids in pear
Sclereids in bean seed coat
Various forms of sclereids
a. Brachysclereid (sel batu) d. Astrosclereid
b. Macrosclereid
c. Osteosclereid
e. Trichosclereid
Sclerieds (stone cells) in fruit tissue of pear
Sclerieds in cross section of a water lily leaf
Sclereids
Fibres - often found among
other tissues of plant
organs
- the shape is more
elongated than wide
- the cavity in the
middle of the cell is
termed lumen
- economic importance
of fibres : for making
ropes, canvas etc.