function of meristematic tissue in plants
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Answers:Meristematic tissues or Meristems : The meristems are situated at the apices (tips) of the actively growing regions of the plants such as shoot apex and root apex. The cells of this tissue continusly divide and add new cells in the plants. The characteristic features of meristmatic tissue are as follows : o The cells are structurally alike and are always living as well as thin-walled. o They are spherical, oval or polygonal. o They are arranged compactly with no intercellular spaces. o They possess abundant cytoplasm with large, prominent nuclei. o The vacuoles if present in the cells may be quite small or altogether absent. o They continuously divide and produce new cells. There are three groups of the meristematic tissues according to their position in the plant body. They are apical meristem, intercalary meristem and lateral meristem. o Apical meristem lies at the tips of the shoot and root, the growing points of the plant. o Intercalary meristems are internodal in their position and are found lying in between masses of permanent tissues, o Lateral meristems occupy lateral position in plant organs such as root and stem.
Answers:A meristem is a tissue in plants consisting of undifferentiated cells (meristematic cells) and found in zones of the plant where growth can take place. Differentiated plant cells, or mature cells , generally cannot divide or produce cells of a different type. Therefore, cell division in the meristem is required to provide new cells for expansion and differentiation of tissues and initiation of new organs, providing the basic structure of the plant body. Meristematic cells are analogous in function to stem cells in animals ( Read about it in a separate para given at the end.), are incompletely or not at all differentiated, and are capable of continued cellular division (youthful). Furthermore, the cells are small and protoplasm fills the cell completely ( Protoplasm means cytoplasm as well as nucleus ). The vacuoles are extremely small. The cytoplasm does not contain differentiated plastids (chloroplasts or chromoplasts), although they are present in rudimentary form (proplastids). Meristematic cells are packed closely together without intercellular cavities. The cell wall is a very thin primary cell wall. STEM CELLS ---Stem cells are primal cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Research in the human stem cell field grew out of findings by Canadian scientists Ernest A. McCulloch and James E. Till in the 1960s. The three broad categories of mammalian stem cells are: 1) Embryonic stem cells, derived from blastocysts, 2 ) Adult stem cells, which are found in adult tissues, and 3) Cord blood stem cells, which are found in the umbilical cord. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells. As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, their use in medical therapies has been proposed. In particular, embryonic cell lines, autologous embryonic stem cells generated through therapeutic cloning, and highly plastic adult stem cells from the umbilical cord blood or bone marrow are touted as promising candidates. In both , stem cells and the meristamatic cell, the common factors are = They are living and nucleated , full of cytoplasm, capable of rapid divisions and totipotent or pluripotent. a) Totipotent = ( Total potency ) that means given a chance they can generate entire organism according to the DNA blue print . b ) Pluripotent = ( Pluri means many ) They can generate many organs or tissues if not all.
Answers:In plants meristematic tissue divides by mitosis. These cells then elongate and then specialise - at which point they are fully developed, specialised and permanent tissue.