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.