The document discusses organ culture, callus culture, and totipotency in plant science. It defines organ culture as the culture of excised plant organs or tissues to allow differentiation while maintaining structure and function. It also discusses the importance of organ culture for studying nutrient and growth factor requirements. Callus culture is defined as the growth of unorganized cell masses from isolated plant cells or tissues on artificial media. The document outlines the principles of callus culture, including aseptic preparation of explants, use of appropriate media and growth regulators, and controlled incubation conditions. It also provides a brief history of callus culture experiments dating back to the 1930s. Totipotency refers to a plant cell's genetic potential to produce an entire

1. Organ Culture: Definition, History and
Importance | Plant Tissues Culture

4. • The organ culture refers to the in vitro culture and
maintenance of an excised organ primordia or whole or
part of an organ in a way that may allow differentiation
and preservation of the architecture and/or function.

5. Importance of Organ Culture
• Organ culture provides an excellent experimental system
to define the nutrients and growth factors normally
received by the organ from other parts of the plant body
and from its external environment.
• (ii) Organ culture is particularly valuable in studies of the
interdependence of organs for growth hormones and
other growth factors.

6. • What is the Meaning of Totipotency?
• Totipotency is the genetic potential of a plant cell to
produce the entire plant. In other words, totipotency is the
cell characteristic in which the potential for forming all the
cell types in the adult organism is retained.
• Expression of Totipotency in Culture:
• The basis of tissue culture is to grow large number of cells in
a sterile controlled environment. The cells are obtained
from stem, root or other plant parts and are allowed to
grow in culture medium containing mineral nutrients, vi-
tamins and hormones to encourage cell division and growth.
As a result, the cells in culture will produce an unorganised
proliferative mass of cells which is known as callus tissue.

8. • Importance of Totipotency in Plant Science:
• The ultimate objective in plant protoplast, cell and tissue
culture is the reconstruction of plants from the totipotent
cell. Although the process of differentiation is still
mysterious in general, the expression of totipotent cell in
culture has provided a lot of information’s.
• On the other hand, the totipotentiality of somatic cells
has been exploited in vegetative propagation of many
economical, medicinal as well as agriculturally important
plant species. Therefore, from fundamental to applied
aspect of plant biology, cellular totipotency is highly
important.

9. • Brief Past History of Callus Culture:
• R. J. Gautheret (France) (1934-1937):
• He first succeeded in promoting the development
of callus tissue from excised cambial tissue of Salix
capraea and other woody species. He was able to
promote the growth of the callus tissue using
simple nutrient medium supplemented with three
vitamins (thiamine, pyridoxine and nicotinic acid)
and indole-3-acetic acid (IAA) newly discovered by
F W Went and K V Thimann (1937).
• ADVERTISEMENTS:

20. • What is the Meaning of Callus Tissue?
• Callus tissue means an unorganised proliferative
mass of cells produced from isolated plant cells,
tissues or organs when grown aseptically on
artificial nutrient medium in glass vials under
controlled experimental conditions.
• Principles of Callus Culture:
• For successful initiation of callus culture, three
important criteria should be accomplished:
• (i) Aseptic preparation of plant material,

21. • (ii) Selection of suitable nutrient medium supplemented with
appropriate ratio of auxins and cytokinins or only appropriate
auxin, and
• (iii) Incubation of culture under controlled physical condition.
• Different plant parts carry a number of surface borne micro-
organisms-like bacteria, fungus etc. So, before attempting to
initiate a callus culture, it is necessary to surface sterilize the plant
parts which are to be cultured. Typical plant parts may be
segments of root or stem, pieces of leaf lamina, flower petals etc.
The excised plant parts called explants are at first washed with
liquid detergent (generally 5% v/v ‘Teepol’).
• Then the explants are surface sterilized by the most commonly
used chemicals such as 0.1% w/v mercuric chloride (HgCl2) or
Sodium hypochlorite (0.8% to 1.6% available chlorine) for a
limited time (generally 10-15 minutes). After surface sterilization,
the explants are repeatedly rinsed with autoclaved distilled water.