%0 Journal Article %1 Martreetal_01 %A Martre, P. %A Cochard, H. %A Durand, J. L. %D 2001 %J Plant, Cell and Environment %K anatomy, bibtex-import, citeulikeExport grass, hydraulics, kleaf, papercopy, techniques %P 65--76 %T Hydraulic architecture and water flow in growing grass tillers %V 24 %X The water relations and hydraulic architecture of growing grass tillers (Festuca arundinacea Schreb.) are reported. Evaporative flux density, E (mmol s 1 m 2), of individual leaf blades was measured gravimetrically by covering or excision of entire leaf blades. Values of E were similar for mature and elongating leaf blades, averaging 24 mmol s 1 m 2. Measured axial hydraulic conductivity, K h (mmol s 1 mm MPa 1), of excised leaf segments was three times lower than theoretical hydraulic conductivity (K t) calculated using the Poiseuille equation and measurements of vessel number and diameter. K t was corrected (K t*) to account for the discrepancy between K h and K t and for immature xylem in the basal expanding region of elongating leaves. From base to tip of mature leaves the pattern of K t* was bell-shaped with a maximum near the sheath-blade joint ( 19 mmol s 1 mm MPa 1). In elongating leaves, immature xylem in the basal growing region led to a much lower K t*. As the first metaxylem matured, K t* increased by 10-fold. The hydraulic conductances of the whole root system, Lproot (mmol s 1 MPa 1) and leaf blades, Lpblade (mmol s 1 MPa 1) were measured by a vacuum induced water flow technique. Lproot and Lpblade were linearly related to the leaf area downstream. Approximately 65 of the resistance to water flow within the plant resided in the leaf blade. An electric-analogue computer model was used to calculate the leaf blade area-specific radial hydraulic conductivity,... The hydraulic design of the mature leaf resulted in low and quite constant xylem water potential gradient ( 03 MPa m 1) throughout the plant. Much of the water potential drop within mature leaves occurred within a tenth of millimetre in the blade, between the xylem vessels and the site of water evaporation within the mesophyll. In elongating leaves, the low K t* in the basal growth zone dramatically increased the local xylem water potential gradient ( 20 MPa m 1) there. In the leaf elongation zone the growth-induced water potential difference was 02 MPa.

@article{Martreetal_01, abstract = {{The water relations and hydraulic architecture of growing grass tillers (Festuca arundinacea Schreb.) are reported. Evaporative flux density, E (mmol s 1 m 2), of individual leaf blades was measured gravimetrically by covering or excision of entire leaf blades. Values of E were similar for mature and elongating leaf blades, averaging 24 mmol s 1 m 2. Measured axial hydraulic conductivity, K h (mmol s 1 mm MPa 1), of excised leaf segments was three times lower than theoretical hydraulic conductivity (K t) calculated using the Poiseuille equation and measurements of vessel number and diameter. K t was corrected (K t*) to account for the discrepancy between K h and K t and for immature xylem in the basal expanding region of elongating leaves. From base to tip of mature leaves the pattern of K t* was bell-shaped with a maximum near the sheath-blade joint ( 19 mmol s 1 mm MPa 1). In elongating leaves, immature xylem in the basal growing region led to a much lower K t*. As the first metaxylem matured, K t* increased by 10-fold. The hydraulic conductances of the whole root system, Lproot (mmol s 1 MPa 1) and leaf blades, Lpblade (mmol s 1 MPa 1) were measured by a vacuum induced water flow technique. Lproot and Lpblade were linearly related to the leaf area downstream. Approximately 65 of the resistance to water flow within the plant resided in the leaf blade. An electric-analogue computer model was used to calculate the leaf blade area-specific radial hydraulic conductivity,... The hydraulic design of the mature leaf resulted in low and quite constant xylem water potential gradient ( 03 MPa m 1) throughout the plant. Much of the water potential drop within mature leaves occurred within a tenth of millimetre in the blade, between the xylem vessels and the site of water evaporation within the mesophyll. In elongating leaves, the low K t* in the basal growth zone dramatically increased the local xylem water potential gradient ( 20 MPa m 1) there. In the leaf elongation zone the growth-induced water potential difference was 02 MPa.}}, added-at = {2019-03-31T01:14:40.000+0100}, author = {Martre, P. and Cochard, H. and Durand, J. L.}, biburl = {https://www.bibsonomy.org/bibtex/2eafd61c895b79b8bbc0115ba90585f00/dianella}, citeulike-article-id = {1523827}, comment = {(private-note)the basal expanding region of the leaf is a hydraulic bottleneck in fescue. (Martre, Durand, Cochard 2000) but this only indirectly affects leaf transpiration, through affecting elave water potential and therefore stomatal conductance (tyree and Ewers 1991) but if stomatal conductance isn't tightly regulated (as it isn't in tall fescue) then it might have a big effect. sealed with sticky tape before putting in pressure bomb with wet tissues. For hydraulic conductivity, leaves were cut into 3cm segments underwater, wrapped around an aluminium bar longitudinally, covered with teroson (sticky putty), wrapped in teflon and fitted into silicon tubing.}, interhash = {d2572a17dcae747e3267e04ae83e45f0}, intrahash = {eafd61c895b79b8bbc0115ba90585f00}, journal = {Plant, Cell and Environment}, keywords = {anatomy, bibtex-import, citeulikeExport grass, hydraulics, kleaf, papercopy, techniques}, pages = {65--76}, posted-at = {2007-07-31 06:38:40}, priority = {0}, timestamp = {2019-03-31T01:16:26.000+0100}, title = {{Hydraulic architecture and water flow in growing grass tillers}}, volume = 24, year = 2001 }