Plants as Phytosensors: Physiological Responses of a Woody Plant in Response to RDX Exposure and Potential for Remote Detection

Abstract

Using plants as phytosensors could allow for large-scale detection of explosives and other anthropogenic contamination. Quantifying physiological, photosynthetic, and hyperspectral responses of plants to hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contamination provides the basis for understanding plant signals for remote detection. Plants of the woody shrub Baccharis halimifolia (a generalist species common on many military installations) were potted in soil concentrations of RDX ranging from 100 to 1500 mg kg−1. Physiological measurements of stomatal conductance and photosynthesis were significantly affected by RDX exposure at all treatment levels, with no overall effect on water potential. However, declines in photosynthesis and stomatal conductance were markedly different from those that occur under natural stress. Quantum use efficiency () and electron transport rate indicated that photosystem II (PSII) of RDX-treated plants was functional, with active photosynthetic reaction centers. Thus, decline...