Class 11 Biology Anatomy of Flowering Plants Simple tissues

Simple tissues

  • The various simple tissues in plants are parenchyma, collenchyma and sclerenchyma.
  1. Parenchyma –
  • Parenchyma forms the major component within organisms, which are generally isodiametric and spherical, oval, round, polygonal or elongated in shape.
  • The walls of parenchyma are made up of cellulose either closely packed or have small intercellular spaces and performs photosynthesis, storage, secretion.

Class_11_Biology_Anatomy_Of_Flowering_Plants_Parenchyma_Tissue

Fig. Parenchyma tissue

  1. Collenchyma-
  • The collenchyma occurs in layers below the epidermis in dicotyledonous plants without intercellular spaces , found either as a homogeneous layer or in patches and consists of cells which are much thickened at the corners due to a deposition of cellulose, hemicellulose and pectin.
  • Collenchymatous cells may be oval, spherical or polygonal and assimilate food when contain chloroplasts.
  • They provide mechanical support to young stem and petiole of a leaf.

Class_11_Biology_Anatomy_Of_Flowering_Plants_Collenchyma_Tissue

Fig. Collenchyma tissue 

  • Sclerenchyma
  • Consists of long, narrow cells with thick and lignified cell walls having a few or numerous pits.
  • They are usually dead and without protoplasts.
  • The fibres are thick-walled, elongated and pointed cells.
  • The sclereids are spherical, oval or cylindrical, highly thickened dead cells with very narrow cavities known as lumen.
  • These are commonly found in the fruit walls of nuts; pulp of fruits like guava.

Class_11_Biology_Anatomy_Of_Flowering_Plants_Sclerenchyma_Tissue

Fig. Sclerenchyma tissue

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