The Use of High-Throughput Phenotyping for Assessment of Heat Stress-Induced Changes in Arabidopsis
Schematic of the experimental setup. (a) WT and hsp101 seedlings were grown in standardized pots supplied by the PlantScreen™ phenotyping system using a checkerboard design across 8 trays, with 10 WT and hsp101 seedlings in each tray. The environment in the growth room was set to a 16/8 h day/night cycle, with 22°C and 60% relative humidity. (b) The phenotyping protocol. Each tray underwent an initial 15 min dark-adaptation period inside the adaptation chamber, followed by chlorophyll fluorescence, red green blue (RGB), and thermal imaging, with automatic weighing and watering before returning to the growth chamber. (c) The heat stress imposition protocol. 22 days after sowing, two trays of plants were kept in the growth chamber as control and other six trays were moved into the preheated 45°C Percival chamber at 9 am, 12 pm, and 3 pm for the 9 h, 6 h, and 3 h heat treatments, respectively. All treated six trays were returned to the growth chamber at 6 pm and imaged daily at 7 pm starting from the day before the heat stress application (DAS -1) until one week after. (d) The overview of the chlorophyll fluorescence protocol executed using the dark-adapted plants. The minimal () and maximal () fluorescence are measured directly after dark adaptation, followed by gradual exposure to increasing light intensities of 95, 210, 320, 440, 555, and 670 μmol m-2 s-1, corresponding to Lss1, Lss2, Lss3, Lss4, Lss5, and Lss6, respectively, where the minimal () and steady-state fluorescence are determined. At each light intensity, plants are exposed to a saturating light flash, which allows measuring the maximum fluorescence at the light-adapted state for a given intensity ().