Ch 5Plant Tissue Culture — Class 12 Botany, concept-first.

Tissue culture is the technique of growing plant protoplasts, cells, tissues or organs away from their normal environment, under artificial, sterile conditions in the laboratory - a process also calle…

Four concepts anchor the whole of plant tissue culture. Totipotency is the foundational one: it is the genetic potential every living, nucleated plant cell carries to develop, when placed in a suitabl…

Plant tissue culture (PTC) is the term used for growing any plant part - protoplast, cell, tissue or organ - in vitro (literally 'in glass', i.e.

Because plant tissue culture depends on maintaining strict aseptic and environmentally controlled conditions throughout, a dedicated laboratory needs several distinct functional spaces working togethe…

Carrying an explant through to a regenerated plantlet is not a single operation but a sequence of linked techniques, each covered as its own subsection below: sterilization of everything the explant w…

Sterilization is the technique used to eliminate microbes such as bacteria and fungi from the culture medium, the culture vessels, and the explant itself, since even a single contaminating cell can qu…

No single medium can support the optimum growth of every kind of plant tissue, so the growth medium's exact composition - together with the plant growth regulators added to it and the physical culture…

Alongside the medium's chemical composition, four physical parameters of the incubation environment must each be held within a narrow optimum range for a culture to grow well.

Callus induction is usually the first visible milestone in a tissue culture experiment. A small, sterile segment of explant - typically 1 to 2 cm, taken from a leaf, stem, tuber or root - is inoculate…

Once a callus has formed, its component cells can go on to differentiate a second time, this time organising themselves into embryo-like structures called somatic embryos, or embryoids (Figure 5.5).

A protoplast is a plant cell that has had its rigid cell wall removed but still retains an intact plasma membrane, and because the cell wall is gone, protoplasts can be induced to fuse with one anothe…

A plantlet that has developed entirely inside a culture vessel has grown under artificially high humidity, a controlled temperature and limited light, and has often relied partly on sugars in its medi…

The four types of plant tissue culture described in this section are distinguished from one another purely by which part of the plant is used as the starting explant - not by any difference in the und…

Organ culture is the culture, on an appropriate medium, of whole plant organs rather than of isolated cells or protoplasts - the organs commonly used include embryos, anthers, ovaries, roots and shoot…

Meristem culture is the in vitro culture of a plant's own meristematic tissue - most often the shoot-tip apical meristem, the small dome of continuously dividing cells at a shoot's growing point.

Having been isolated and fused (section 5.3.2.6), a protoplast still has to be cultured under carefully controlled conditions before it can regenerate into a plant.

Cell suspension culture is the growth of cells directly in a liquid medium, whether as single cells or as small aggregates of cells, and is prepared by transferring a portion of an existing callus int…

Plant regeneration is the process by which a complete plant is rebuilt from an explant, and sections 5.3 through 5.3.3 have already covered the raw material (the explant) and the intermediate stage (c…

Somatic embryogenesis is the formation of embryos - called embryoids - directly from callus tissue, or alternatively from pre-embryonic cells that differentiate directly out of cultured cells without…

Organogenesis is the alternative plant regeneration pathway, in which morphological changes in callus tissue lead directly to the formation of shoots and roots, rather than to an embryo-like structure…

Plant tissue culture techniques translate directly into a wide range of practical applications. The book lists six major ones: producing improved hybrids through somatic hybridisation; encapsulating s…

Micropropagation is the industrial-scale application of tissue culture to multiply plants that are genetically identical to a single parent, and it is used at commercial scale to maintain high standar…

Artificial (synthetic) seeds, or synseeds, are manufactured using embryoids - somatic embryos produced through in vitro culture (section 5.4.1) - though they can equally be built up from single cells…

Field-grown perennial crops are routinely infected by a wide range of pathogens - fungi, bacteria, mycoplasma and viruses - that cause significant economic losses, and while chemical treatments can us…

Beyond generating individual plants for research or commercial use, tissue culture techniques also give plant scientists tools to conserve genetic diversity itself.

Germplasm conservation refers to the conservation of living genetic resources - pollen, seeds or plant tissue - maintained specifically for the purposes of selective plant breeding, preservation in a…

Cryopreservation, also called cryo-conservation, is the process of preserving biological material - protoplasts, cells, tissues, organelles, organs, extracellular matrix, enzymes, or virtually any oth…

Intellectual Property Right (IPR) is a legal category of property covering intangible creations of the human intellect - it primarily consists of copyrights, patents and trademarks, but also extends t…

A patent is a special right granted to an inventor or discoverer by a government, through legislation, allowing them to trade a new invention commercially.

Advances in biotechnology are almost always accompanied by controversy, mainly because so much of modern biotechnology involves manipulating genetic material directly.

Biotechnology has, within a relatively short span of time, grown into a comprehensive scientific venture spanning both academic research and commercial application - a transformation the book traces d…

This Evaluation section closes the chapter with 20 questions. Questions 1-10 are objective-type (four-option) questions covering totipotency, micropropagation, the basic-concepts vocabulary (dediffere…

Sample papers and previous-year board questions for this subject.