Monitoring the water content of plant leaves with THz time domain spectroscopy

We present an automated measurement setup which employs a fiber-coupled THz time domain spectrometer for simultaneous monitoring of the change in leaf water content of several plants at once. Moreover, it combines the collected THz spectra with data from other sensors. While the strong absorption of THz radiation by polar liquids like water tends to a problem in most biological and medical applications, it is a reliable indicator for leaf water content. We take this well-known basic principle to a level where biological experiments which explore the physiological behavior of plants under different drought stress condition become possible.