![]() (7) Development of plants resistant to weedicides.- Information Management: Detailed staff, students, guardians data storage options Flexible multi-parameters security model Configurable dashboard and menu options Support for multi-school networks and multi-site schools Regionalisation of date and currency Extensible class, subject, course, users, etc. (6) It shortens the period of development of new varieties. (5) Somatic cell hybrid plants can be grown by tissue culture. (4) Haploid plants and from them, homozygous plants can be successfully produced. (3) Embryo culture overcomes seed dormancy and helps in producing viable plants from hybrid crosses. (2) Virus-free plants can be grown from virus-infected plants through shoot culture. (1) Tissue culture is a method of rapid multiplication or asexual reproduction, especially for rare plants which reproduce through seeds with difficulty. This indicates that this also involves all regular stages of embryonic development. (3) During the development of a normal plant from a single isolated cell in culture, stages resembling to globular heart-shaped and torpedo-shaped embryos are formed. Steward estimated that as many as 1,00,000 embryoids can be obtained from a single carrot embryo and each of these embryoids can grow into a normal flowering plant. ![]() When rotation is stopped, each cell grows out into an embryoid. The callus is placed in a liquid culture medium and is rotated continuously so that its cells get isolated. Steward and his co-workers (1963) and Halperin and Wetherell (1964) demonstrated that in carrots, the callus raised from an immature embryo can be made to differentiate into several embryoids. When these embryoids were transferred to a semisolid nutrient medium, each one developed into a whole plant that developed flowers and produced seeds. Some of these cell clusters developed roots. By gently shaking the culture, the callus separates into isolated cells and groups of cells floating in the culture medium. They took 2 mg pieces of phloem tissue of mature carrot roots in a special flask containing liquid medium supplemented with coconut milk. Success to grow isolated cells was achieved by Steward and his coworkers ( 1957) of Cornell University, U.S.A. ![]() However, Haerlnadt’s experiment to grow isolated green cells failed. He thought that since each cell of the organism is derived from the fertilized egg and contains the same hereditary information, it should be able to regenerate the whole plant. Cellular totipotency was first proposed by German botanist Haberlandt in 1902.
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