Tissue - a collection of cells having a common origin, performing one or more functions, occupying their characteristic position in the plant organism, and intercellular substance. The organs of the plant are formed by different tissues.
Tissue Classification
- Fabrics are divided into simple and complex . Simple called tissue, consisting of cells more or less the same in shape and function. Complex tissues are composed of cells that are different in form and function, but are closely interconnected in their vital functions. An example of the former is columnar chlorenchyma , spongy chlorenchyma, collenchyma , and secondly, xylem , phloem .
- Tissues are divided into educational ( meristem ) and permanent .
- Specialized tissues are called educational, whose cells retain a long-term ability to divide, ensuring the growth of the plant and its individual organs. Given the position in the body of the plant, they are divided into apical (or apical, located on the root and shoot apexes), intercalary (or inserted, peculiar to the shoot - the stem and leaves, located in the internodes and petioles) and lateral (or lateral, mainly present in axial organs - in the root and stem of gymnosperms and dicotyledonous angiosperms).
- Constant is called tissue whose cells have lost the ability to divide (fully or potentially retain it) and specialize in performing other functions: protective, storage, mechanical, conducting, etc. Given the origin, prevailing function and position in the plant body, permanent tissues, in turn, they are divided into integumentary , conductive, and basic integuments , the beginning of which with primary growth is given respectively by the protoderm , procambium, and main meristem.
- Along with the anatomical and physiological, there is an ontogenetic classification of tissues based on their origin and time of appearance in the process of organ morphogenesis . According to this classification, tissues are divided into primary and secondary .
- Primary meristems originate from the first cell of a new organism - zygotes , which are characterized by the ability to divide. They are the first to form when a new organism is laid and provide its primary growth. These are the apical and intercalary meristems. Those permanent tissues whose cells differentiate from derivatives of primary meristem cells are called primary. These include tissues: primary integumentary, primary conductive and basic.
- Secondary are called meristems, which are formed in the vegetative organs later than the primary ones and provide their secondary growth. These are lateral meristems - cambium and fellogen (cork cambium). Permanent tissues, which were derived from derivatives of the secondary meristem, are called secondary. These include secondary integumentary tissue, secondary conductive tissue.
See also
- Plant anatomy
Literature
- Biological Encyclopedic Dictionary / Ch. ed. M.S. Gilyarov ; Editorial: A.A. Baev , G.G. Vinberg, G.A. Zavarzin et al. - M .: Sov. Encyclopedia , 1986.- S. 633.- 831 p. - 100,000 copies.