Q: Discuss in detail the history of plant tissue culture with reference

to India. 10 marks

Ans: Plant tissue culture is a process of growing plant cells, tissues or organs in an
artificial nutrient-rich environment under controlled conditions. It was first introduced in
the early 20th century, and over the years, it has become a crucial tool in plant science,
agriculture and biotechnology.

The history of plant tissue culture can be traced back to the late 19th century when
scientists first started to explore the potential of plant cells to grow outside of their
natural environment. One of the earliest pioneers in this field was the German botanist
Julius von Sachs (1832-1897), who first described the process of growing plant cells in
a nutrient-rich environment. He was interested in understanding the basic biology of
plants and developed a method for growing plant tissues in vitro (in a glass vessel).

In the early 20th century, two German botanists, Hans Knop (1865-1918) and Wilhelm
Hofmeister (1824-1877), made important contributions to the field of plant tissue
culture. Knop was the first to successfully cultivate plant cells in vitro and demonstrated
that cells grown in this manner could be used for breeding and propagating plants.
Hofmeister, on the other hand, studied the process of plant embryogenesis and was the
first to describe the process of organogenesis in plants.
The theoretical basis for plant tissue culture was proposed by Gottlieb
Haberlandt in his address to the German Academy of Science in 1902 on his
experiments on the culture of single cells. He experimented with isolated
photosynthetic leaf cells and other functionally different cells and was
unsuccessful, but nevertheless, he predicted that one could successfully cultivate
artificial embryos from vegetative cells. On the basis of that 1902 address and
his pioneering experimentation before and later, Haberlandt is justifiably
recognized as the father of plant tissue culture. . Most importantly he suggested
the concept of totipotency.

Gottlieb Haberlandt

Embryo culture also had its beginning early in the first decade of the last century
with barley embryos. This was followed by the successful rescue of embryos
from nonviable seeds of a cross between Linum perenne X Linum austriacum.
The 1940s, 1950s, and 1960s proved an exciting time for the development of
new techniques and the improvement of those already available. The application
of coconut water (often incorrectly referred to as coconut milk) allowed for the
culture of young embryos and other recalcitrant tissues, including monocots.
Callus cultures of numerous species, including a variety of woody and
herbaceous dicots and gymnosperms, as well as crown-gall tissues, were
established as well.

From 1902 to 1930 attempts were made for organ culture. Hannig (1904) isolated
embryos of some crucifers and successfully grew on mineral salts and sugar
solutions. Simon (1908) successfully regenerated a bulky callus, buds, and roots
from poplar trees on the surface of a medium containing IAA which proliferated
cell division.

The two important discoveries made in the mid-1930s which gave a big push to
the development of plant tissue culture technique were: (a) identification of auxin
as a natural growth regulator and (b) recognition of the importance of B vitamins
in plant growth.

In 1934, Gautheret cultured cambium cells of some tree species (Salix capraea ,
Populus nigra ) on Knop's solution containing glucose and cysteine hydrochloride
and recorded that they proliferated for a few months.

From 1940 to 1970, suitable nutrient media were developed for the culture of
plant cells, tissue, protoplasts, anthers, roots tips and embryos.

In 1957, Skoog and Miller put forth the concept of hormonal control of organ
formation. Murashige was instrumental in giving the techniques of in vitro culture
a status of a viable practical approach to the propagation of horticultural species.
He worked extensively for the popularization of the technique by developing
standard methods for in vitro propagation of several species ranging from ferns
to foliage, flower and fruit plants.

In 1959, the discovery of kinetin was promoted by F. Skoog along with C.O. Miller
and co-workers. Demonstrating induction of regeneration of shoots in tobacco
callus paved the way for the multiplication of plants by tissue culture. In the
1960s, E. Cooking for the first time developed a method for the isolation of
protoplasts in large quantities using the fungal enzyme obtained from
Myrothecium sp.

In India, work on tissue culture was started during the mid-1950s at the
Department of Botany (University of Delhi) by Panchanan Maheshwari who is
regarded as the father of embryology in India. During the 1960s the Botany
School at the University of Delhi, led by P. Maheshwari, became actively
engaged with in vitro culture of reproductive organs of flowering plants.
 P Maheswari

Different tissue culture methodologies were involved for morphogenic studies