FREEZE-PRESERVATION OF RICE CELLS GROWN IN SUSPENSION CULTURE

A simple procedure has been worked out for the freeze‐preservation of rice (Oryza sativa L.) cells grown in suspension culture. The protocol differs in some interesting aspects from those established for other organisms. A peculiar feature of this procedure is that growth of freeze‐recovered rice cells resumes after an extremely short lag period of 2–8 days and proceeds with a growth rate identical to that of untreated cells. This, together with data obtained with viability tests, rules out the possibility that selection of freeze‐resistant mutant cells may occur, as postulated with other plant cells where growth resumption was considerably delayed in time. The viability of freeze‐recovered rice cells, when assessed at time zero after thawing by measuring the mitochondrial respiratory efficiency, was 60–65% of that of untreated cells. However, the limits of this and other viability tests in determining the efficiency of the freeze preservation methods and the percentage of surviving cells were shown by experiments in which cell viability and cell growth were followed in cultures initiated with freeze‐recovered rice cells. Copyright © 1979, Wiley Blackwell. All rights reserved