Studies on the determination of dead or diseased tissues. I. Investigations on dead plant tissues

Abstract

To diagnose the vitality of portions of poisoned roots of skeleton weed (Chondrilla juncea L.) and bindweed (Convolvulus arvensis L.) in the field, probe readings of equivalent parallel resistance (Rp) and capacitance (Cp) were made, and it was found that the lowest point of dead tissues was usually within one-quarter of an inch of the point at which the value of Rp was minimal. Values of Cp did not give any indication of the phase angle of the tissue under test, but gave a useful cross check on the location of the minimum for Rp. Probe readings at 100 kc/s. served to discriminate between living and dead portions of the one root having similar values for Rp at 1 kc/s. Readings at 100 kc/s. also served to distinguish some abnormally swollen poisoned roots.