Estimating tomato water consumption by sap flow measurement in response to water stress under greenhouse conditions

This research was conducted to determine the water consumption of tomato plants, the effects of water stress on stem sap flow (SF) and its response to climatic factors. SFs in 100% irrigation (T-1), 75% (T-2) and 50% (T-3) of irrigation amount of T-1 were monitored using Dynagage sensors. Compared to T-1, the difference in SF was observed under deficit irrigation in the same climatic conditions on sunny days although there was no apparent difference between T-1 and T-2 on cloudy days. Under T-1, the correlation and regression relationships between SF and climatic factors were analyzed at daytime (6: 00-22: 00), morning (6: 00-14: 00) and afternoon (14: 00-22: 00). Considering daytime, the order of sensitive indicators to SF was VPD > LI > Ta and LI > VPD > Ta for the Fall-Winter sunny days and Spring-Summer season, respectively. The water uptake over SFs measured for Fall-Winter and Spring-Summer periods were calculated as 168.65 and 229.18 mm, respectively.