Reply to: Comment on 'neutron imaging reveals internal plant water dynamics'

Our recent publication (Warren et al., Plant Soil 366:683-693, 2013) described how pulses of deuterium oxide (D2O) or H2O combined with neutron radiography can be used to indicate root water uptake and hydraulic redistribution in maize. This technique depends on the large inherent differences in neutron cross-section between D and H atoms resulting in strong image contrast. However, as illustrated by Carminati and Zarebanadkouki (2013) there can be a change in total water content without a change in contrast simply by a change in the relative proportions of D2O and H2O. We agree with their premise and detailed calculations (Zarebanadkouki at al. 2012, 2013), and present further evidence that mixing of D2O and H2O did not confound evidence of hydraulic redistribution in our study.