CTC

• Micropropagation is a method of propagating plants by culturing very small parts of it called explants.
• Micropropagation is true-to-type propagation of selected genotypes using in vitro culture techniques.
• Micropropagation provides a rapid and reliable system for production of a large number of genetically uniform disease-free plantlets.
• Micropropagation is one of the important contributions of plant tissue culture to commercial plant propagation and has vast significance.
• The art and science of multiplying plants in vitro is known as plant tissue culture.
• In bamboo, one multiplication cycle takes 3 weeks, allowing for 17 such cycles in a year.
• The widespread interest in using tissue culture to mass clone ornamental plants began in the 1960s.
• A gerbera daisy grower in Southern California visited Dr. Murashige at the University of California, Riverside campus with the problem of producing specific flower colours due to the mixture of flower colours resulting from seed propagation.
• Dr. Murashige developed a protocol for gerbera clonal propagation with the grower.
• Soon ornamental producers all over the United States were setting up tissue culture labs.
• Acclimatised plantlets are produced in multiple shoot formation in 5 L Balloon Type Bubble Bioreactors (BTBB).
• The advantages of using temporary immersion bioreactors in a plant bio-factory include decreased demand for labour, reduced use of appliances and jars, reduction in the space required for the micropropagation of plants, reduction in electricity costs for plant cultivation, total or partial elimination of the use of gelling agents, significant increase in the multiplication rate of the cultivated materials, significant increase in the quality of the plants produced, and larger, well rooted, easily acclimatized plants with fewer losses.
• Apple plantlets are produced in a BTBB after 40 days of culture.
• Garlic plantlets show microbulb formation in BTBB after 40 days of culture.
• The initial cost of an installation may appear too high when compared to that of traditional bio-factories.
• Disadvantages of micropropagation include requiring skilled/trained workers and specialized techniques, high laboratory investment and maintenance cost, and high loss of micropropagated plants during hardening and transfer to field.
• Disadvantages of using a bioreactor in a bio-factory include the potential for large plant losses due to contamination, the problem of hyperhydricity which can be easily addressed by adjusting the immersion time of the materials, and the need to solve problems arising from sterilization in a bioreactor system by a set of chemical sterilizations and preparation of liquid culture media in industrial autoclaves.
• The advantages of micropropagation include rapid mass propagation to produce genetically uniform plants, making clones of species which are very slow growing and very difficult to propagate by any other means, and the process can be carried out throughout the year.
• Large-scale production of apple plantlets is possible after using a bioreactor system.
• Techniques used to suppress this metabolic sequence include: adding antioxidants to the medium, pre-soaking the explants in antioxidant solutions, sub-culturing to a fresh medium on signs of enzymatic browning, and providing little or no light during the initial period of culture.
• The most important aspect of commercial micropropagation is the economics involved and the unit cost of a plantlet.
• Using a liquid medium instead of a gelled medium for large scale micropropagation and a bioreactor as the culture vessel has significantly accelerated production and reduced the unit cost of plantlets.
• Commercial micropropagation involves high costs due to engaging skilled labour, with estimates of labour costs running from 50% to as high as 85% of total production cost.
• Solutions to develop high-tech micropropagation methods involving minimum labour input and production of an unlimited number of quality plants through the refinement of tissue culture procedures are being explored.
• Toshio Murashige is a Professor Emeritus of University of California Riverside in plant biology, most widely known for his efforts in creating the plant tissue culture medium known as Murashige and Skoog medium.
• Professor Emeritus Toshio Murashige defined three steps or stages (I-III) in the in vitro multiplication of plants.
• A fourth stage (I-IV), at which plants are transferred to the external environment, is now commonly recognized.
• The treatment and preparation of stock plants should be regarded as Stage 0.
• Stage 0: Mother plant selection and preparation requires healthy and disease-free stock plants, with choice of explants such as shoot tips.
• Pre-treatment of explants can involve physical and chemical treatments of stock plants.
• Stage I: Establishment of axenic/aseptic cultures involves placing tissue into culture and having it initiate microshoots.
• In the first stage of micropropagation, the goal is to optimize a surface disinfestation protocol and nutrient medium for survival and growth of the explant.
• A 2 litres bioreactor could be used to induce 0.2-0.4 million carrot somatic embryos.
• The objective of micropropagation is reproducibility, not 100% success.
• Plant organs such as shoots, microtubers, corms, embryos, etc., have been successfully proliferated in the bioreactor.
• The elongated shoots are cut from the original culture and are sub-cultured as nodal explants, these may have the leaves removed and are typically 2 to 4 nodes in length.
• Shoot regeneration and plantlet growth from PLB in the bioreactor
• Stage I of micropropagation involves placing tissue into culture and having it initiate microshoots, usually a batch of explants is transferred to culture at the same time.
• Phalaenopsis pro-trocorm-like bodies (PLB) proliferation in the bioreactor (1 L column-type) after 5 weeks
• After a short period of incubation, any container found to have contaminated explants or medium is discarded.