Cytokinesis - In Animal and Plant Cell

Cytokinesis In Animal Cell: 

         late telophas the astral micro tubules send signals to region of the cell. Where actin and myosin are activated which form contratile ring, followed by cleavage furrow, which deepens towards the centre of the cells dividing the parent cell into two daughter cells.

Cytokinesis In Plant Cell: 

                        At cytokinesis, in plant of contratile ring a membrane structure phragmoplast is formed from vesicles which originate form golgi complex. These vesicles originate actually during metaphase, line up in the centre of the dividing cell, where they fuse to form phragmoplast at the end of telophase. The membrane of vesicles becomes the plasma membrane of daughter cells. The vesicles also contain materials for future cell wall such as precursors of cellulose and protein.

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Secondary growth In Plants - Stems & Roots

Apical or primary growth increases the length of stems and roots. Secondary growth is the increase in diameter of stem and root due to activity of secondary meristem called cambium. Initially the cambium is restricted to a series of small group of cells. The first step in secondary growth involves the linking of these groups to form a ring of cambium, tissue between xylem and phloem. It is achieved by radical cambium, of cambium cells. Cells of cambium ring divide tangentially to form secondary xylem tissues on the inside and secondary phloem on the side. In the stem similar columns of parenchyma are formed within the secondary xylem and phloem forming secondary medullary rays.

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