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Influence of evaporative demand on aquaporin expression and root hydraulics of hybrid poplar
Author(s) -
ALMEIDARODRIGUEZ ADRIANA M.,
HACKE UWE G.,
LAUR JOAN
Publication year - 2011
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/j.1365-3040.2011.02331.x
Subject(s) - transpiration , populus trichocarpa , botany , biology , aquaporin , water transport , horticulture , microbiology and biotechnology , photosynthesis , environmental science , water flow , gene , environmental engineering , biochemistry , genome
When light levels and evaporative demand increase, dynamic physiological changes in roots may be required to restore the water balance at the whole plant level. We hypothesized that a dynamic increase in root hydraulic conductance ( L P ) and aquaporin (AQP) expression could moderate the transpiration‐induced drop in water potential ( Ψ ), allowing continued gas exchange in hybrid poplar ( Populus trichocarpa × deltoides ) saplings. Fifty‐six AQP s have been identified in poplar, but little information about their expression patterns in roots is available, especially from a whole‐plant water relations perspective. We measured AQP expression and L P in plants subjected to different levels of light and evaporative demand. Shaded plants had only one‐tenth the root area of plants growing at higher light levels. Shade‐grown saplings experiencing a sudden increase in light exhibited a threefold higher L P than plants remaining in shade. This dynamic increase in L P corresponded with increased transcript abundance of 15 AQP s out of a total of 33 genes simultaneously assessed by quantitative RT‐PCR. The tissue‐level localization of transcripts of four AQP s was studied with in situ hybridization. Comprehensive expression profiling in conjunction with physiological and morphological measurements is a valuable reference for future studies on AQP function in poplar.