lecture plants tissues authors as. kernychna i.z
DESCRIPTION
1.Meristematic tissues. 2. Dermal tissues. 3. Secretory tissues. Plan 1.Meristematic tissues. 2. Dermal tissues. 3. Secretory tissues. 4. Parenchyma.TRANSCRIPT
LecturePLANTS TISSUES
Authors as. Kernychna I.Z.
Plan1.Meristematic tissues.
2. Dermal tissues.3. Secretory tissues.
4. Parenchyma.
In the body plants cells not isolated, but placed groups - on the basis of community of origin, structure and functions. These groups of cells name tissues.
Many classification
Living and dead;meristematic and constant;Simple and complex;Primary and secondary
The tissues of a plant are The tissues of a plant are organized into three tissue organized into three tissue systems: the dermal tissue systems: the dermal tissue system, the ground tissue system, the ground tissue system, and the vascular system, and the vascular
tissue systemtissue system
Classification
tissues
Simple tissues are:Simple tissues are: Parenchyma
Chlorenchyma Collenchyma
Sclerenchyma Complex tissues are:Complex tissues are:
DERMALDERMALXYLEMXYLEM
PHLOEMPHLOEM
Meristematic tissues:
the cells are small,
the cells walls are thin,
cells have large nuclei,
vacuoles are absent or very small, and
there are no intercellular spaces.
Plants have four types of meristems: apical, lateral, intercalary, and wound
(or regeneration).
Dermal tissues cover the plant body
There are two types of There are two types of dermal tissuedermal tissue::
The primary is:The primary is:epidermisepidermis
The secondary is:The secondary is:peridermperiderm
Epidermis is closely packed,
without intercellular spaces
or chloroplasts. The outer walls
may be covered waxy, waterproof
cuticle
Guard cells contain chloroplasts and regulate gas exchange between the inside of the leaf and the surrounding air.
Trichomes- on plants are epidermal outgrowths of various kinds.
Trichomes may be unicellular
or multicellular,branched or unbranched
Branched hairs can be dendritic
(tree-like), tufted, or stellate (star-shaped).
Epidermal hairs lower water loss by decreasing the flow of air over the plant surface, which in turn, slows the loss of water from the plant.
Glandular hairs (secretory) prevent herbivory by storing substances that are harmful to insects.
Root hairs increase water uptake by increasing the surface area of the cell.
Epidermis is short lived in many plants. When epidermis ruptures a secondary dermal
tissue periderm that concist of phellogen (cork cambium),phellem (cork),
phelloderm (secondary cortex) replaces it.
SECRETORY TISSUES OF PLANSSECRETORY TISSUES OF PLANS secretory structures: secretory structures:
external secretory structures (nectaries, hydathodes, secretory hair)external secretory structures (nectaries, hydathodes, secretory hair)- internal secretory structures- internal secretory structures
(secretory cells, canals, ducts, cavities, laticifers).(secretory cells, canals, ducts, cavities, laticifers).
Resin canalsResin canals
Internal secretory structure:- - laticiferslaticifers ( (ofof danteliondantelion););
OIL CANALS
ParenchymaParenchyma
Types parenchymaTypes parenchyma
1. Chlorenchyma1. Chlorenchyma2. Aerenchyma2. Aerenchyma
3. Storage parenchyma3. Storage parenchyma
Chlorenchyma
: contains chloroplasts and functions in photosynthesis
Chlorenchyma of leaves
STORAGE STORAGE PARENCHYMPARENCHYM
AA:: characterizecharacterize
d by large d by large accumulatioaccumulatio
ns of ns of storage storage
products products such as such as starch, starch,
protein, oil, protein, oil, hemicellulohemicellulose or water.se or water.
Aerenchymacontains large intracellular air spaces and functions in gas exchange.