Biology – Tissues – Notes For W.B.C.S Examination.

জীববিজ্ঞান – টিস্যু – WBCS পরীক্ষার জন্য নোট।

  • A group of cells that are similar in structure and work together to accomplish a particular function is known as tissue.Continue Reading Biology – Tissues – Notes For W.B.C.S Examination.
  • Tissues are categorized as −
    • Plant Tissue &
    • Animal Tissue
  • Let’s discuss them in brief −

Plant Tissue

  • Following are the major types of plant tissue −
    • Meristematic Tissues
    • Permanent Tissues
      • Simple Permanent Tissues
        • Parenchyma
        • Collenchyma
        • Sclerenchyma
        • Epidermis
      • Complex Permanent Tissue
        • Xylem
        • Phloem

Meristematic Tissue

  • Meristematic tissue mainly consists of actively dividing cells, and helps in increasing the length and thickening the stems of the plant.
  • Meristematic tissue, commonly, present in the primary growth regions of a plant, for example, in the tips of stems or roots.
  • Depending on the region (where the meristematic tissues are found); meristematic tissues are classified as apical, lateral, and intercalary (see the image given below).
  • Apical meristem (as shown in the above image) is present at the growing tips of stems and roots and helps in their growth.
  • Lateral Meristem is found in stem or root region and helps in their growth.

  • Intercalary meristem is found at the base of the leaves or internodes (on twigs) and helps in growth.

Permanent Tissue

  • Cells of meristematic tissue later differentiate to form different types of permanent tissue.
  • Permanent Tissue is further categorized as −
    • Simple Permanent Tissue and
    • Complex Permanent Tissue

Simple Permanent Tissue

  • Simple Permanent Tissue further categorized as −
    • Parenchyma
    • Collenchyma
    • Sclerenchyma
    • Epidermis
  • Parenchyma tissue provides support to plants and also stores food.
  • Sometimes, parenchyma tissue contains chlorophyll and performs photosynthesis, in such a condition, it is known as collenchyma.
  • The collenchyma tissue provides flexibility to plant and also provides mechanical support (to plant).
  • The large air cavities, which are present in parenchyma of aquatic plants, give buoyancy to the plants and also help them float, are known as aerenchyma.
  • The Sclerenchyma tissue makes the plant hard and stiff. For example, the husk of a coconut is made up of sclerenchymatous tissue.
  • The cells of Sclerenchyma tissue normally are dead.
  • The outermost layer of cells is known as epidermis.
  • The epidermis is usually made up of a single layer of cells.
  • The entire surface of a plant has the outer covering of epidermis, which protects all the parts of the plant.

Complex Permanent Tissue

  • The complex tissue, normally, consists of more than one type of cells which work together as a unit.
  • Complex tissues help in the transportation by carrying organic material, water, and minerals up and down in the plants.
  • Complex Permanent Tissue is categorized as;
    • Xylem and
    • Phloem
  • Xylem, normally, consists of tracheid, vessels, xylem parenchyma, and xylem fibers.
  • Xylem is accountable for the conduction of water and mineral ions/salt.
  • Phloem, normally, is made up of four types of elements namely −
    • Sieve tubes
    • Companion cells
    • Phloem fibers and
    • Phloem parenchyma
  • Phloem tissue transports food from leaves to other parts of the plant.

Our own publications are available at our webstore (click here).

For Guidance of WBCS (Exe.) Etc. Preliminary , Main Exam and Interview, Study Mat, Mock Test, Guided by WBCS Gr A Officers , Online and Classroom, Call 9674493673, or mail us at – mailus@wbcsmadeeasy.in
Visit our you tube channel WBCSMadeEasy™ You tube Channel
Please subscribe here to get all future updates on this post/page/category/website
"WBCS