INVESTIGATIONS ON THE RELATIONSHIP BETWEEN WINTERHARDINESS IN ROSES AND THE ELECTRIC IMPEDANCE MEASURED DURING THE GROWING PERIOD
Differences were found in the electric impedance of rose cultivars and seedlings, measured periodically under greenhouse and field cultures. Generally, plants with the highest ranking means were also hardy, but the magnitude of the impedance was not strictly indicative of hardiness since hardy plants were found with relatively low impedances.Fluctuations in the weekly impedance measurements corresponded to the rise and fall of the air temperature. The impedance was negatively correlated to the temperature. Different impedance temperature regression coefficients were were found for different cultivars and seedlings. It is not known how these temperature gradients should be interpreted biologically, but it is assumed that they are significant for the adaptation of plants.