Promeristem or Primordial meristem: The promeristem originates from embryo and, therefore, called primordial or embryonic meristem. It is present in the regions where an organ or a part of plant body is initiated. Primary meristem: A primary meristem originates from promeristem and retains its meristematic activity. It is located in the apices of roots, stems and the leaf primordia. Secondary Meristem: They always arise in permanent tissues and have no typical promeristem.
Some living permanent cells may regain the meristematic nature. Apical meristem: This meristem is located at the growing apices of main and lateral shoots and roots. These cells are responsible for linear growth of an organ. Intercalary meristem: These are the portions of apical meristems which are separated from the apex during the growth of axis and formation of permanent tissues. It is present mostly at the base of node (e.g., Mentha viridis-Mint), base of internode (e.g., stem of many monocots viz., Wheat, Grasses, Pteridophyts like Equisetum) or at the base of the leaf (e.g., Pinus).Lateral meristem: These meristems occur laterally in the axis, parallel to the sides of stems and roots. This meristem consists of initials which divide mainly in one plane (periclinal) and result increase in the diameter of an organ. According to function: Haberlandt in 1890 classified the primary meristem at the apex of stem under the following three types : Protoderm: It is the outermost layer of the apical meristem which develops into the epidermis or epidermal tissue system. Procambium: It occurs inside the protoderm. Some of the cells of young growing region which by their elongation and differentiation give rise to primary vascular tissue constitute the procambium. Ground meristem: It constitutes the major part of the apical meristem develops ground tissues like hypodermis, cortex, endodermis.
NOTE: jigssolanki.in does not own this book neither created nor scanned. We just providing the link already available on internet. If any way it violates the law or has any issues then kindly mail us: email@example.com or Contact Us for this(Link Removal).