ESTIMATION OF COLD RESISTANCE OF HIGHER-PLANTS FROM ELECTROPHYSIOLOGICAL ANALYSIS OF THEIR EXCITABILITY

Bioelectric responses arising during excitation of stem cells in reply to their gradual, local, physiological moderate, and reversible cooli ng have been investigated on cucumber seedlings using extracellular ma croelectrodes. It is demonstrated that the rise of cold resistance ach ieved by hardening is linked with changes in a whole series of paramet ers of registrable bioelectric responses, the most significant of whic h is increase in critical temperature of the phase of fast pulsive dep olarization of the response to the second cooling in relation to the a nalogous index during the first cold influence. No reliable difference s are clarified in the nature of bioelectric responses in seedlings wi th different cultivar-related cold hardiness, but the above-indicated ratio is correlated with individual cold resistance within limits of t he same cultivar. The proposed method of determining cold resistance i s recommended for testing within cultivar limits, estimating the effec tiveness of hardening procedures, and breeding.