Design, development, and assessment of a High-Throughput Screening (HTS) system for the macroscopic root water uptake modeling

Climate change is responsible for the increasing frequency and intensity of abiotic stresses generating water scarcity conditions. There is a need to breed plants adapted to future environmental conditions and resistant to water stress. This study presents a High-Throughput Screening (HTS) system for continuously and simultaneously monitoring plant stress response to drought in a semi-controlled environment. The HTS system combines a gravimetric weighing system with soil moisture and atmospheric sensors. In operative terms, the system was tested on the Sage (Salvia officinalis L.) under two soil water deficit treatments managed according to a feedback control irrigation scheduling. The system was able to model the sage water stress function following the root water uptake macroscopic approach. The threshold of soil water status below which crop water stress occurred was also identified. The gravimetric-based daily evapotranspiration (ETa) and the time domain reflectometry (TDR)-based root wateruptake (RWU) rates showed a high correlation during the drying when the evaporation flux is minimal. Moreover, the effects of soil bulk density on the root density and the plant biomass were evaluated, indicating the importance of carrying out a homogeneous procedure of the pot-filling process.