PLANT TISSUE

PLANT TISSUE



TYPES  OF PLANT TISSUE

Meristematic tissue

  • actively dividing cells

  •  Found in growing areas of the plant and at the roots and stem

  • Also called as meristem

  • includes terminal roots and stem,

  • dermal

  • vascular

Permanent tissue

  • not actively dividing cells

  • no longer grows

  • Found in flowers and leaves

  • For support, transport of minerals, and aid of food storage.

Apical meristem

  • Primary growth of plants(height)

  • Elongates the shoots and root

  • Found on the tips of shoots and roots

  • Derivatives of apical meristem 

    • Protoderm

      • Gives rise to epidermis 

    • Procambium 

      • gives rise to xylem and phloem

    • Ground meristem

      • Gives rise to ground tissues

Lateral meristem

  • Secondary growth of the plant (girth and diameter)

  • Periderm

    • protective tissue formed during secondary growth

  • Derivatives of lateral meristem 

    • Vascular cambium

      • Gives rise to secondary phloem/xylem

      • Cell division by the cambium produces outward growth of phloem and inward growth of xylem

      • Xylem layers become thickened and forms wood

    • Cork cambium

      • Gives rise to cork cells 

      • Makes up the bark composed of phloem and cork layers

      • Cork

        • protection from diseases

      • Suberin

        • waxy protection produced by the cork to prevent water loss

      • Simple permanent tissue

        • Composed of only one type of cell

        • ground (see below for types)

          • neither dermal or vascular, is found between

          • fillers of the plant and the bulk in the center.

          • Pith ground tissue found in the center of the stem that transports and stores nutrients 

          • Cortex

            • exterior part of vasculartissue.

          Epidermis 

          • Protects the upper and lower parts of the leaves

          • Covers the whole plants

          • Protected by a waxy Cuticle,

            • protective film preventing  loss of water and evaporation

          • Lower epidermis of leaf has guard cells which regulate the opening and closing of the stomata

          • Stomata

            • slit structure that aids in the exchange of gasses

          • Root hair

            • the epidermis in roots that increases absorption capacity

          • Trichomes

            • tiny growths in the leaves that reflects excess light

  • Types of ground tissue 

  1. Parenchyma

    Found in all parts of the plant

    1. Least specialized 

    2. chloroplast and performs photosynthesis 

    3. plastids that store starch

  1. Collenchyma 

    1. flexible support For young and immature stems and petioles

    2. Even thickness lacking in secondary walls such as lignin

  2. Sclerenchyma 

    1. Has thick secondary walls of lignin making it more rigid

Complex permanent tissue

Composed of two kinds of cells

  • Vascular tissues

    • Xylem

      • For the distribution of water and minerals

    • Tracheids

      • elongated Conducting cells in the xylem where water passed through

    • A conducting cells of xylem is the Vessel elements that are are perforated meaning it has holes which aids in water transport

  • Phloem 

    • no nucleus and ribosomes for more efficient sugar transport 

    • Distributes sucrose throughout the body 

    • Has sieve tube elements allowing transport of nutrients