Tissue System The dermal or Epidermal Tissue System

Tissue System The dermal or Epidermal Tissue System 2. The Fundamental or Ground Tissue System 3. The Vascular Tissue System 1.

Promeristem Protoderm Epidermis Epidermal Tissue system Procambium General meristem Vascular bundle Ground meristem Vascular tissue system Cortex, pericycle, medulary ray, pith

The Dermal Tissue System The Epidermis Functions of Epidermis i) Protect the internal soft tissue against mechanical injury ii) Prevent excessive transpiration iii) Store water in xerophytic plant iv) Secretory substances

Structures of epidermal cells Morphology B) Arrangement C) Cell contents D) Wall structures A)

Special epidermal structures � 1. Lithocytes �Deposition of calsium carbonate crystal �Arranged in the form of bunches, like those of grapes �Such deposition is called cystolith and cells containing them are called lithocytes

2. Myrosin cell �Contain special sac-like cells scattered in the epidermis �Filled with enzyme myrosin, called myrosin cells �These are idoblastic cell

3. Scleretic cells �Epidermal cells contain sclereids 4. Bulliform cells Bubble like cells are found in certain grass family Bulliform cells are mainly water containing cells Less amount of chlorophyll content

5. Stomata 1. Ranunculaceous or Anomocytic 2. Cruciferous or Anisocytic 3. Rubiaceous or Paracytic 4. Diacytic stomato

Anomocytic Paracytic Anisocytic Diacytic

6. Trichome A. Non-glandular trichomes i) Unicellular trichome ii) Multicellular trichome B. Glandular trichomes Include unicellular and multicellular trichomes which secret a sticky substances

7. Root hairs �Unicellular, elongated �Arises from the epidermal cells of roots �They are usually absent in aquatic roots

Hairs or Trichome i) Unicellular ii) Multicellular iii) Stinging hairs iii) Scale or peltate hairs

Vascular Tissue �Conducting strand known as vascular bundle �Xylem and phloem

Origin of vascular tissue �Procambium �Cambium

Arrangement �Exarch �Endarch �Mesarch

Types of Vascular bundle Radial 2. Conjoint 3. Concentric 1.

Radial �Xylem and phloem are found as separate patchs on alternate radii

Conjoint �Xylem and phloem occur side by side on the same radius A. Collateral i) Open type ii) Closed type B. Bicollateral i) Open type ii) Closed type

Concentric �One complex tissue remains surrounded by other Amphivasal or leptocentric B. Amphicribal or hadrocentric A.