One major problem in plant breeding is that crosses can only be made between closely related parental types. This makes it very difficult to introduce new genes into a plant species.
The solution to this problem is PROTOPLAST FUSION - protoplasts of different plants are mixed and fused together. These form a binucleate cell containing a nucleus from both parental types
Protoplast = actively metabolising part of cell minus cell wall [cell wall digested by enzymes]
Process of Plant Cell Culture
1. Plant cells treated with cellulase & pectinase to remove the cell wall which is composed of cellulose, pectin and small amount of hemicellulose. These enzymes only break down the cell wall leaving the plasma membrane intact
2. The cells are then incubated with a mineral salt solution containing mannitol for several hours. This sugar exerts osmotic pressure causing PLASMOLYSIS leading to easier digestion 3. In order for the protoplasts to grow they must be put in a suitable medium to encourage cell wall growth
4. EXPLANTS (small pieces of young growing plant tissue e.g. root, shoot, bud or leaf) can be taken and grown in a suitable medium containing plant growth regulators (growth hormones e.g. auxins and cytokinins whuch cause tissue differentiation). Cell proliferation produces a CALLUS (a mass of dividing, undifferentiated cells) 5. With continued sub-culturing and changing the balance of growth regulators, the new roots and shoots can be planted out to regenerate a complete plant !
Monoculture growing from callus tissue
All plant cells are totipotent - they each have the ability to express the full genetic potential of that plant
Plant cell culture explants from plants medium with nutrients and PGRs cell proliferation callus formation adult plants submerged culture in fermenters rapid production of plant cell products control of temp, light, nutrients