Net photosynthetic rate
Net photosynthetic rate (PN)
To illustrate the effect of KCPF application and drought stress on gas exchange in leaves, net photosynthetic rate (PN) was determined. According to the results of experiment, it was observed that there was a progressive reduction in PN under severe drought stress condition (50% FC) in 2016 and 2017 season respectively. PN content was affected by KCPF application. KCPF reduced PN in both years. The lowest PN content (57 % lower than non- kaolin treatment) was observed with 7 % KCPF application in the 2nd season. Plants that foliar sprayed with 7 % KCPF in 50 % FC, showed a lower PN (52 and 56 %) than plants that without KCPF application in the same drought stress conditions in the 1st and 2nd season respectively (Figure 3 a, b).
During the measurement period of physiological variables, drought stress significantly (P? 0.01) reduced stomatal conductance by approximately 43% in 2016 and 50% in 2017 (Figure 3 a, b). KCPF application decremented stomatal conductance at all drought stress treatments in both seasons and maximum decrease in stomatal conductance (89%) was observed in severe drought stress level (50 % FC) with 7 % KCPF application in the 1st season (Figure 3 a, b).
Effect of KCPF and drought on leaf temperature
The temperature response of leaf under drought stress levels and KCPF application in two consecutive years is shown in Figure 3 (e, f). In all treatments, leaf temperature decreased with increasing KCPF application. Treatment with 5% KCPF application showed a significantly higher reduction (approximately 11%) in 50 % FC than leaves without KCPF treatment (control leaves) in both years, while