tissue culture: the initial step of micropropagation where plant cells or organs are grown on a nutrient medium in a sterile environment
tissue culture steps:
selection of an explant
culturing on a nutrient medium
forming a callus
developing it into a specific organ or cell
Tissue culture is used for fusion of plant cells, increase in the number of sets of chromosomes, and production of pathogen-free plants
micropropagation: a technique of tissue culture that involves growing plantlets in sterile conditions
micropropagation steps:
selection of a mother plant
multiplication of plantlets in a culture
pretransplant (preparing of plantlets for transfer from the culture to soil)
Micropropagation is used for the production of large quantities of identical plantlets
Tissue culture is the starting step of micropropagation where plant cells or organs are grown on a nutrient medium, whereas micropropagation is the production of thousands of identical plantlets
totipotency: a single cell has the genetic program to grow an entire plant
cell potency: a cells ability to differentiate into other cell types
Totipotent stem cells can differentiate into any cell
Pluripotent stem cells can differentiate many cell types but not all
Multipotent stem cells can differentiate into some cell types
Unipotent stem cells can differentiate into only one cell type
A high cytokinin to auxin ratio tends to promote shoot organogenesis
A low cytokinin to auxin ratio promotes rooting
More equal concentrations of auxin and cytokinin tend to promote both shoots and roots
structures formed in tissue culture:
plantlets
seedlings
callus
somatic embryos
micropropagation stages:
Stage 0: donorplantselection
Stage I: establishment
Stage II: shoot multiplication
Stage III: root formation
Stage IV: acclimitization
Things to pay attention to with donor plant selection:
genetic and epigenetic characteristics of the source plant
control of pathogens
physiological conditioning of the source plant to optimize its ability to establish in a culture
recalcitrant: species or plants non-responsive to tissue culture
important aspects of the establishment stage:
explant type
explant disinfestation
culture medium
stabilization
in vitro: production in a test tube or other similar vessel where culture conditions and medium are controlled for optimum growth during tissue culture
ex vitro: rooting of microcuttings occurs using greenhouse growing medium rather than rooting in vitro where cuttings are rooted on agar in a test tube
explant disinfestation: the process of removing microbial contaminants from the surface of explants