title: Monitoring plant drought stress response using terahertz time-domain spectroscopy.
abstract: We present a novel measurement setup for monitoring changes in leaf water status using nondestructive terahertz time-domain spectroscopy (THz-TDS). Previous studies on a variety of plants showed the principal applicability of THz-TDS. In such setups, decreasing leaf water content directly correlates with increasing THz transmission. Our new system allows for continuous, nondestructive monitoring of the water status of multiple individual plants each at the same constant leaf position. It overcomes previous drawbacks, which were mainly due to the necessity of relocating the plants. Using needles of silver fir (Abies alba) seedlings as test subjects, we show that the transmission varies along the main axis of a single needle due to a variation in thickness. Therefore, the relocation of plants during the measuring period, which was necessary in the previous THz-TDS setups, should be avoided. Furthermore, we show a highly significant correlation between gravimetric water content and respective THz transmission. By monitoring the relative change in transmission, we were able to narrow down the permanent wilting point of the seedlings. Thus, we established groups of plants with well-defined levels of water stress that could not be detected visually. This opens up the possibility for a broad range of genetic and physiological experiments.
authors: Faculty of Physics and Material Sciences Center, Philipps-University Marburg, D-35032 Marburg, Germany.
authors: Norman
authors: N
authors: Born
authors: David
authors: D
authors: Behringer
authors: Sascha
authors: S
authors: Liepelt
authors: Sarah
authors: S
authors: Beyer
authors: Michael
authors: M
authors: Schwerdtfeger
authors: Birgit
authors: B
authors: Ziegenhagen
authors: Martin
authors: M
authors: Koch
mesh_terms: D028202:Abies / Q000502:physiology*; D018533:Biomass; D055864:Droughts; D036226:Seedlings / Q000502:physiology; D013312:Stress, Physiological; D055068:Terahertz Spectroscopy / Q000379:methods*; D013997:Time Factors; D014867:Water
chemical_list: D014867:Water