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Stomatal responses to changes in vapor pressure deficit reflect tissue‐specific differences in hydraulic conductance
Author(s) -
OCHELTREE T. W.,
NIPPERT J. B.,
PRASAD P. V. V.
Publication year - 2014
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12137
Subject(s) - transpiration , vapour pressure deficit , stomatal conductance , conductance , limiting , botany , water use efficiency , hydraulic resistance , horticulture , chemistry , agronomy , biology , photosynthesis , mathematics , physics , mechanical engineering , combinatorics , mechanics , engineering
The vapor pressure deficit ( D ) of the atmosphere can negatively affect plant growth as plants reduce stomatal conductance to water vapor ( g wv ) in response to increasing D , limiting the ability of plants to assimilate carbon. The sensitivity of g wv to changes in D varies among species and has been correlated with the hydraulic conductance of leaves ( K leaf ), 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 K leaf was correlated with the hydraulic conductance of large longitudinal veins ( K lv , r 2 = 0.81), but was not related to K root ( r 2 = 0.01). Stomatal sensitivity to D was correlated with K leaf relative to total leaf area ( r 2 = 0.50), and did not differ between C 3 and C 4 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 ‘apparent feedforward’ response. For these individuals , E began to decline at lower values of D in plants with low K root ( r 2 = 0.72). These results show the significance of both leaf and root hydraulic conductance as drivers of plant responses to evaporative demand.