Tag: tissue culture

• In sexual reproduction, two offsprings have the same genetic material and the same body features are called identical twins.
• They are two offspring produced by the same pregnancy.
• Twins have the same genetic material and the same body features because they develop from a single fertilized egg, they have the same genome.
• So, the correct answer is 'Twins'.

In plant tissue culture, an explant is the initial plant tissue piece that is introduced into the culture medium. This explant will then proliferate, differentiate, and regenerate into whole plants through various tissue culture techniques like organogenesis or somatic embryogenesis.

Tissue culture is a collection of techniques used to grow cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition ( in vitro). The emergence of this technique became a turning point when polio virus, could be cultivated in vitro, a discovery of Enders, Weller, and Robbins (1949). This led to the feasibility of quantitative metabolic studies in animal viruses. Tissue culture is, therefore, today a vital part of life science research ( across plants and animals ) and in every area of research that includes bacteriology, embryology and virology.

• The callus is an unspecialized, unorganized, growing and dividing the mass of cells.
• It produced when explants are cultured on the appropriate solid medium, with both auxin and cytokinin in correct conditions.
  
• In Callus culture, Auxins increase root growth and cytokinins increase shoot growth.
• Hence Cytokinin increase shoot growth in callus culture.
• So, the correct answer is 'Cytokinin'.

Plant cells are totipotent. Hence, plant cells can be cultured to grow entire plants. In-plant tissue culture, a small meristematic tissue called explant is used to generate a mass of undifferentiated cells called callus. Entire plantlets can be generated from callus by applying a carefully balanced ratio of phytohormones.

totipotency is the ability of a plant to use all its genes and form a new plant. to prove this F.C Steward did an experiment on the root cells of the carrot plant with which he produced a whole new carrot plant.

The potential of the somatic cell to grow and develop into a multicellular and multi-organed organism through the technique of cloning is referred to as cellular totipotency. While German botanist Gottleib Haberlandt introduced the concept of in vitro cell culture, Prof. F.C. Steward of Cornell University worked to show that cellular totipotency is an inherent capability of every single cell. Thus, the correct answer is option A.

Totipotency is the ability of a single cell to divide and produce all of the differentiated cells in an organism. Spores and zygotes are examples of totipotent cells. In the spectrum of cell potency, totipotency represents the cell with the greatest differentiation potential. Many somatic plant cells, including some fully differentiated types (e.g., leaf mesophyll), provided they contain intact nuclear, plastid and mitochondrial genomes, have the capacity to regenerate into whole plants. 

Somaclonal variation is the variation seen in plants that have been produced by plant tissue culture. Chromosomal rearrangements are an important source of this variation. The term somaclonal variation is a phenomenon of broad taxonomic occurrence, reported for species of different ploidy levels and for outcrossing and inbreeding, vegetatively and seed propagated and cultivated and non-cultivated plants. Characters affected include both, qualitative and quantitative traits. Somaclonal variation is seen in tissue culture grown plants.
Somaclonal variation is not restricted to, but is particularly common in, plants regenerated from callus. The variations can be genotypic or phenotypic, which in the latter case can be either genetic or epigenetic in origin.
Typical genetic alterations are: changes in chromosome numbers (polyploidy and aneuploidy), chromosome structure (translocations, deletions, insertions and duplications) and DNA sequence (base mutations). A typical epigenetics-related event would be gene methylation.

Explant is any portion taken from a plant that will be used to initiate a culture. It can be a portion of the shoot or of the leaves or even just some cells. Thus, the correct answer is option C.