Callus initiation and maintenance from potato tuber in biotechnology laboratory

Callus was initiated from explants of tubers of the Norchip cultivar of
Solanum tuberosum L. and grown on medium with a single carbon
source and without addition of coconut milk, protein hydrolysate, or
amino acid. Callus samples were harvested at intervals and compared to
mature tubers for which there was good biochemical knowledge.
The amino acid spectrum, the glycoalkaloid content, and the proper-
ties of the isolated invertase and sucrose synthetase were similar in callus
and in tuber. Significantly the level of sucrose synthetase varied with the
age of the developing callus just as it did with the age of the developing
tuber. Of greater significance, levels of reducing sugars and invertase
varied with the age of developing caOlus and also with time and tempera-
ture of storage after the callus has ceased growth. Similar changes occur
in intact tubers.
Callus and tuber biochemistry differed in the amount of deposited
starch and in the absence of potato invertase inhibitor.