Visualization of embolism formation using cold neutron radiography

Formation and repair of xylem embolism are of great importance for plant water relations, but are not easy to monitor. Tötzke et al. examine intact and cut stems of the lianas Adenia lobata, Aristolochia macrophylla and Parthenocissus tricuspidata using cold neutron radiography, and use image processing to distinguish between low attenuation gas spaces and high-attentuation (water-containing) plant tissue. They find that the formation and temporal course of an embolism event can be successfully observed in individual conduits, and dehydration of the whole stem section can be monitored via decreasing attenuation of the neutrons. The method, which has a low energy dose compared with synchrotron X-ray radiation, thus provides a useful tool for the non-invasive study of water relations in plant stems.