The behaviour of the averaged normalized sensor response parameter (NR) used to monitor the drought response of cv. Ikram plants subjected to drought stress. DS: period during which water was withheld; RE: rewatering recovery phase. The data represent the mean of four well-watered (control) and four stressed plants. The various phases have been highlighted by grey boxing: PI—sensor insertion, PII—drought stress, DA—drought avoidance, and PIII—post-rewatering recovery.