This document discusses callus and suspension cultures. Callus culture involves culturing explants on agar medium to form an unorganized cell mass called callus. Suspension cultures involve culturing tissues or cells in liquid medium, producing single cells and clumps. There are three types of suspension cultures: batch, continuous, and immobilized. Batch cultures use a limited nutrient supply until growth declines. Continuous cultures drain out used medium and add fresh medium to maintain a steady state. Immobilized cultures encapsulate plant cells in gels like agarose.

1. CALLUS & SUSPENSION
CULTURES
Lecture #7

2. • CALLUS CULTURE
• When explants are cultured on a suitable GR combination,
many of its cells undergo division.
• Even mature and certain differentiated, e.g., Parenchyma
and often Collenchyma, cells undergo changes become
meristematic; its called as “Dedifferentiation”.
• Dedifferentiation involves enhanced RNA and Protein
synthesis.

3. • Types of Cultures:
CULTURES
SUSPENSION
CULTURE
IMMOBILIZED
BATCH
CONTINUOUS
CALLUS
CULTURE

4. • CALLUS CULTURE:
• Tissues and cells cultured on an agar gelled
medium form and unorganised mass of cells called
callus.
• These culture need to be sub-cultured every 3-5
weeks.
• Risk free, easy to handle.

8. • SUSPENSION CULTURES:
• Tissues and cells cultured in liquid medium is
known as Suspension culture.
• They often produce suspension of single cells and
clumps.
• Liquid cultures are constantly agitated, generally by
a gyratory shaker @ 100-250ppm.
• This enhances the aeration and dissociation of cell
clumps into smaller pieces.

9. • This suspension cultures are used for large scale
production.
• Need to be sub-cultured every week.
• The suspension cultures are majorly three types
1. Batch cultures
2. Continuous cultures
3. Immobilized cultures

10. • Batch cultures:
• A technique used to grow microorganisms or
cells.
• A limited supply of nutrients for growth is
provided; when these are used up, or some
other factor becomes limiting, the culture
declines.
• Cells, or products that the organisms have
made, can then be harvested from the culture.
• The cell number or biomass of batch culture
exhibits a typical sigmoidal growth curve.

12. • LAG Phase: during this phase cell number or
biomass is unchanged.
• LOG Phase: during this phase the cell number
rapidly increases in geometrical progression.
• Stationary Phase: In this phase end phase where
cell number does not change.

13. • Batch cultures are maintained by sub-culturing.
• These cultures are mostly used in initiation of
cell suspension i.e. single cell culture.
• These are most convenient to use than
continuous cultures hence mostly used.

14. • Continuous culture:
• These cultures are maintained in a steady state for
a long period by draining out the used (or) spent
medium and adding the fresh medium.
• such subculture systems are either closed (or) open
type.
• Closed:
• The cells separated from used medium taken out
for replacement and added back to the suspension
culture.
• So that the cell biomass keeps on increasing.

15. • Open:
• Both cells and the used medium are taken out from
open continuously cultures and replaced by equal
volume of fresh medium.
• The replacement volume is so adjusted that
cultures remain at sub-maximal growth indefinitely.

16. • Immobilized cell cultures:
• Plant cells and cell groups may be
encapsulated in a suitable material, e.g.,
agarose and calcium alginate gels.
• These gel beads are placed on a suitable
frame structures or may be packed in a column
of a membrane wire cloth.
• Liquid medium is continuously run through the
column to provide aeration to cells.