01773nas a2200145   4500008004100000245012100041210006900162300001300231490000700244520125100251100002001502700002301522700001901545856006301564       2014                        eng d00aStomatal responses to changes in vapor pressure deficit reflect tissue-specific differences in hydraulic conductance0 aStomatal responses to changes in vapor pressure deficit reflect   a132 -1390 v373 a<p>The vapor pressure deficit (D) of the atmosphere can negatively affect plant growth as plants reduce stomatal conductance to water vapor (gwv) in response to increasing D, limiting the ability of plants to assimilate carbon. The sensitivity of gwv to changes in D varies among species and has been correlated with the hydraulic conductance of leaves (Kleaf), but the hydraulic conductance of other tissues has also been implicated in plant responses to changing D. Among the 19 grass species, we found that Kleaf was correlated with the hydraulic conductance of large longitudinal veins (Klv, r2&thinsp;=&thinsp;0.81), but was not related to Kroot (r2&thinsp;=&thinsp;0.01). Stomatal sensitivity to D was correlated with Kleaf relative to total leaf area (r2&thinsp;=&thinsp;0.50), and did not differ between C3 and C4 species. Transpiration (E) increased in response to D, but 8 of the 19 plants showed a decline in E at high D, indicative of an &lsquo;apparent feedforward&rsquo; response. For these individuals, E began to decline at lower values of D in plants with low Kroot (r2&thinsp;=&thinsp;0.72). These results show the significance of both leaf and root hydraulic conductance as drivers of plant responses to evaporative demand.</p>1 aOcheltree, T.W.1 aNippert, Jesse, B.1 aPrasad, P.V.V.  uhttps://onlinelibrary.wiley.com/doi/full/10.1111/pce.12137