CTC Plant Lu 1

• Plant tissue culture is the aseptic culture of cells, tissues, organs and their components under defined physical and chemical conditions in vitro.
• Plant tissue culture is an important tool in both basic and applied studies, as well as in commercial application.
• The theoretical basis for plant tissue culture was proposed by Gottlieb Haberlandt, a German physiologist, in his address to the German Academy of Science in 1902 on his experiments on the culture of single cells.
• Gottlieb Haberlandt experimented with isolated photosynthetic leaf cells and other functionally differenced cells and was unsuccessful, but nevertheless he predicted that one could successfully cultivate artificial embryos from vegetative cells.
• The physical, observable transition from a nonembryogenic cell to an embryogenic cell in somatic embryogenesis appears to occur when the progenitor cell undergoes an unequal division, resulting in a larger vacuolate cell and a small, densely cytoplasmic (embryogenic) cell.
• The embryogenic cell then either continues to divide irregularly to form a proembryonal complex or divides in a highly organized manner to form a somatic embryo.
• Somatic embryogenesis is another important way to regenerate new plants in plant tissue culture.
• A businessman wishes to venture into the new business of propagating and selling high-quality disease-free ornamental and fruit plants in Sarawak.
• Gottlieb Haberlandt clearly established the concept of totipotency and indicated that the technique of cultivating isolated plant cells in nutrient solution permits the investigation of important problems from a new experimental approach.
• Each group must pass up only one written assignment.
• The businessman should design/layout his tissue culture laboratory and the tissue culture system(s) he will require to succeed at his new business venture, giving details and the reasons why in his advice.
• Steward et al. (1958) demonstrated that even single cells from carrot vascular phloem retain totipotency, the capacity to regenerate whole plants, highlighting the astonishing regenerative potential of plant somatic cells.
• The earliest step toward plant tissue culture was made by Henri-Louis Duhumel du Monceau in 1756, during his pioneering studies on wound-healing in plants, observed callus formation.
• Extensive microscopic studies led to the development of the cell theory by Schleiden (1838) and Schwann (1839), which holds that the cell is the unit of structure and function in an organism and therefore capable of autonomy.
• In 1904, Hannig successfully cultured mature embryos from seeds of several species of crucifers.
• In 1908, Simon established the basis for callus culture.
• In 1926, Went discovered the first plant growth hormone, Indoleacetic acid (natural auxins).
• White (1934) introduced vitamin B as a growth supplement in tissue culture media for tomato root tips instead of using yeast extract.
• Rhizogenesis from nodulated callus can be achieved by maintaining a 5-week-old culture of leaf disc on MS + NAA.
• Embryogenesis starts from a single embryogenic cell, i.e. zygote (the product of the fusion of an egg and a sperm during fertilization) or an undifferentiated callus cell.
• In the process of re-differentiation, a tissue called organ primordia is differentiated from a single or a group of callus cells.
• De novo shoot and root organogenesis in leaf disc cultures can be achieved by maintaining an 8-week-old culture of leaf disc on MS + BAP, showing shoot differentiation from brown and dark-green, nodulated, compact callus developed at the cut end of the explant.
• During the embryonic development, the polar axis of the plant is established, domains that set up the organization of the plant body are defined, and the primary tissue and organ systems are delineated.
• Control of the process of differentiation in plant tissue cultures is dependent upon the presence of auxin and cytokinin.
• De-differentiation begins shortly after the isolation of the explant tissues with an acceleration of cell division and a consequent formation of a mass of undifferentiated cells, called callus.
• Re-differentiation, also called budding in plant tissue cultures, may begin any time after the first callus cell forms.
• Embryos developing from zygotes are called zygotic embryos, while those derived from somatic cells are called somatic embryos.
• The process of formation of an embryo is called embryogenesis.
• Organogenesis in plant tissue culture involves two distinct phases: de-differentiation and re-differentiation.
• Skoog and Miller (1957) demonstrated that root and shoot formation from undifferentiated callus of tobacco was dependent upon the balance of auxin and cytokinin, and this was found to be true for other species.
• An individual shoot from the 8-week-old culture of leaf disc on MS + BAP, after transfer to MS + BAP, has elongated well and developed into a multinodal structure.
• An elongated shoot from the 5-week-old culture of leaf disc on MS + NAA, after transfer to ¼ MS + IBA, has developed healthy and branched roots directly from the basal cut end.
• The 1940s, 1950s, and 1960s proved an exciting time for the development of new CTC techniques and the improvement of those already available.
• These secondary products of industrial interest include antimicrobial compounds, antitumor alkaloids, food flavors, sweeteners, vitamins, insecticides, and enzymes.
• High concentration of auxin promotes rooting and high kinetin induces bud formation or shooting.
• Morel (1960) recognized the potential of micropropagation for clonal propagation of orchids.
• Plants have developed a greater ability to adapt to extreme environmental conditions, allowing them to alter their metabolism, growth, and development to best suit their environment.
• Van Overbeek et al. (1941) established the importance of coconut water for the growth and development of young Datura embryos.
• Industrial applications involve large-scale suspension cultures capable of synthesizing significant amounts of useful compounds.
• For example, whether the inserted gene will be integrated into the host genome, transcribed, and expressed in the mature plant.