BIOLOGY 2

• A tissue is a group of closely associated cells that perform related functions and are similar in structure.
• PLANT TISSUE

  A) Xylem

  B) Phloem

  C) Ground Tissue

  D) Dermal Tissue (Epidermis))

  E) Vascular Tissue

  
• Plant tissues can be classified as:

  A) Meristematic tissue

  
• Plant tissues can be classified as:

  A) Permanent tissue

  
• The growth of plants occurs in certain specific regions. This is because the dividing tissue, known as meristematic tissue. Composed of actively dividing ceIIs, responsible for the production of ceIIs. Capacity for division is restricted to certain parts of the plant body called meristems, which are active throughout the life of the plant body.
• Procambium - forms vascular bundles; composed of procambial cells; develop into xylem and phloem
• Meristematic tissues (A)

  A) Apical Meristem

  B) Leaf Primordium

  C) Procambium

  
• Meristematic tissues (B)

  A) Ground Meristem

  B) Procambium

  C) Protoderm

  
• Meristematic tissues (C)

  A) Epidermis

  B) Cortex

  C) Pith

  D) Vascular Tissue

  
• Meristematic tissues (D)

  A) Epidermis

  B) Primary Phloem

  C) Primary Xylem

  D) Pith

  E) Procambium

  F) Cortex

  G) Vascular Tissue

  
• Apical meristems – found at the tip of stems & roots.
• Lateral meristems – a.k.a. cambia
• Lateral meristems - found along the sides of roots & stems; increase width or diameter of stems & roots.
• Types of Lateral Meristems - Vascular Cambium , Cork Cambium
• Intercallary meristems – found at the bases of young leaves & internodes; - responsible for further lengthening of stems & leaves.
• Permanent tissues - Tissues that attained their mature form and perform pacific functions; They stop dividing.
• Types of Permanent Tissues- Simple permanent tissues, Complex permanent tissues
• Simple permanent tissues - consist only of one kind of cells.
• Dermal / surface tissue - external tissues; forms protective covering of the plant body a. Epidermis b. Periderm
• Epidermis - the outermost layer of the primary plant body; covers the leaves, floral parts, fruits, seeds, tems and roots; generally only one layer thick with cuticle.
• Epidermis- composed mostly of unspecialized cells, either parenchyma and/or sclerenchyma.
• Epidermis- contains trichomes, stomata, buIIiform ceIIs (in grasses).
• Structure of Epidermis

  A) Vein

  B) Cuticle

  C) Cuticle

  D) Stoma

  E) Guard cell

  F) Spongy mesophyll cell

  G) Lower epidermis

  H) Phloem

  I) Xylem

  J) Bundle sheath cell

  K) Palisade mesophyll cell

  L) Upper epidermis

  
• Stomata - pores for gas exchange; present on one or both surfaces of Leaves.
• Structure of Stomata

  A) Guard cell

  B) Epidermal cell

  C) Thickened inner wall of guard cell

  D) Nucleus

  E) Stoma

  F) Chloroplast

  G) Epidermal cell

  H) Guard cell

  I) Stoma

  
• Cuticle – Lines the outer waII of the epidermal ceIIs; made up of waxy material that protects plants from desiccation
• C_T__L_

  A) Cuticle

  
• Trichomes – outgrowths of epidermal ceIIs.
• Periderm (Bark) is the outermost layer of stems and roots of woody plants such as trees.
• 1. Parenchyma - are the general purpose ceIIs of plants; cells are rounded in shape & have uniformly thin walls found in all parts of the plants. Living at maturity, have large vacuoles.
• Parenchyma - located Ieaf, stem (pith), roots, fruits
• 2. ChIorenchyma - A specialized parenchyma tissue found in the green parts of the shoot and performs photosynthesis; differentiate from parenchyma cells & are alive at maturity.
• Functions of ChIorenchyma- Support & elasticity and Degeneration
• 3. ScIerenchyma cells which are non-living and lack protoplasts at maturity; have thick, lignified secondary walls. Provide strength and support in parts that have ceased elongating or mature.
• Types of Sclerenchyma- ScIereids or stone cells and Fibers
• Vascular Tissues - Specialized for long-distance transport of water and dissolved substances. Contain transfer ceIIs, fibers in addition to parenchyma and conducting ceIIs. Located in the veins in Ieaves.
• Types of Vascular Tissues- Xylem and Phloem
• Xylem - GW xyIos w/c means “wood” transports water and dissolved nutrients from the roots to aII parts of a plant. Direction of transport is upward.
• There ate two types of Xylem

  
  

  Primary xylem – differentiates from procambium in the apical meristem & occurs throughout the primary plant body.

  
  

  Secondary xylem – differentiates from vascular cambium & is commonly called wood.
• Xylary elements – the conducting cells in xylem.