Control of Vascular Sap pH by the Vessel-Associated Cells in Woody Species (Physiological and Immunological Studies)

Fromard, Louise; Babin, Valérie; Fleurat‐Lessard, Pierrette; Fromont, J. C.; Serrano, Ramón; Bonnemain, Jean‐Louis

doi:10.1104/pp.108.3.913

Cited by 63 publications

(44 citation statements)

References 25 publications

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“…However, the contribution of different pathways to K lam appears to be species specific (Aasamaa and Sõber 2005;Sack et al 2005) and K lam is likely differentially regulated. Changes in the xylem permeability of tree branches can be brought about by solutemediated changes in xylem permeability (Zwieniecki 2001) mediated by the phloem (Zwieniecki et al 2004) or by xylem parenchyma cells (Fromard et al 1995). These effects still remain to be proven in leaves.…”

Section: Discussionmentioning

confidence: 99%

Diurnal and seasonal changes of leaf lamina hydraulic conductance in bur oak (Quercus macrocarpa) and trembling aspen (Populus tremuloides)

Voicu

Zwiazek

2010

Trees

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The aim of this study was to examine the diurnal and seasonal variations in the sensitivity of leaf lamina (K lam ) hydraulic conductance to irradiance in bur oak (Quercus macrocarpa Michx.) and trembling aspen (Populus tremuloides Michx.), which vary in their responses of K lam to irradiance. K lam was determined using the highpressure method and the measurements were carried out in June, August and September. The irradiance response of K lam in bur oak was present throughout the day and declined in senescing leaves. In trembling aspen, K lam declined from morning to late afternoon and drastically decreased before the onset of leaf senescence, but it was not sensitive to irradiance. In both tree species, the capacity of the petioles to supply water to leaf lamina changed during the day in accordance with the ability of the leaf lamina to transport water. Petiole hydraulic conductivity (K pet ) declined during the season in bur oak leaves, while it tended to increase in trembling aspen leaves. There was no correlation between the K lam values and air temperature or light intensity at the time of leaf collection. For trembling aspen, K pet was negatively correlated with the air temperature suggesting sensitivity to drought. We conclude that the water transport properties of petioles and leaf lamina in the two studied tree species reflect their ecological adaptations. Trembling aspen leaves have high hydraulic conductivity and high stomatal conductance regardless of the irradiance level, consistent with the rapid growth and high demand for water. In contrast, the increased lamina hydraulic conductivity and stomatal conductance under high irradiance in bur oak trees reflect a water conservation strategy.

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Section: Discussionmentioning

confidence: 99%

Diurnal and seasonal changes of leaf lamina hydraulic conductance in bur oak (Quercus macrocarpa) and trembling aspen (Populus tremuloides)

Voicu

Zwiazek

2010

Trees

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“…The absence of plasmodesmatal connections between vessels and VACs (Catesson 1983;Czaninski 1987), implies that nutrients must cross their plasma membrane as they do towards companion cells in the phloem (Bonnemain & Fromard 1987;Oparka & Santa Cruz 2000). In Robinia xylem tissue, Fromard et al (1995) showed that the plasma membrane H + -ATPase, which generates the driving force for active transport of nutrients, was located in VACs. Interestingly, our data from two independent immunolocalization studies shows that JrSUT1, a putative sucrose transporter, and JrAHA, an H + -ATPase are both localized to VACs.…”

Section: Jrsut1 Is Localized To Vacsmentioning

confidence: 99%

“…There is also a certain amount of circumstantial evidences supporting the presence of an H + /sugar symporter: (1) VACs are symplastically connected to other parenchyma cells and apoplastically connected to vessels, which implies that sucrose influx needs a membrane transporter (Catesson 1983;Czaninski 1987); (2) like companion cells, VACs exhibit a high respiratory activity which is a characteristic of cells specialized in the apoplastic transport of assimilates (Catesson & Czaninski 1967;Sauter 1972;Alves et al . 2001); (3) plasma membrane H + -ATPase, that generates the proton-motive force required to drive the secondary active transport, was localized to plasma membrane of VACs (Fromard et al . 1995;Arend et al .…”

Section: Introductionmentioning

confidence: 99%

JrSUT1, a putative xylem sucrose transporter, could mediate sucrose influx into xylem parenchyma cells and be up‐regulated by freeze–thaw cycles over the autumn–winter period in walnut tree (Juglans regia L.)

Decourteix

Alves

Brunel

et al. 2005

Plant Cell & Environment

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JrSUT1 , a putative xylem sucrose transporter, could mediate sucrose influx into xylem parenchyma cells and be upregulated by freeze-thaw cycles over the autumn-winter period in walnut tree ( Juglans regia L.) MÉLANIE ABSTRACTSucrose has been reported to play multiple roles in the winter biology of temperate woody species. However, no report on the molecular basis of sucrose transport in xylem tissue has yet been made. In the walnut tree, it is demonstrated that during the autumn-winter period, active absorption of sucrose from xylem vessels to parenchyma cells (sucrose influx) is much higher when samplings were taken shortly after a period of freezing temperatures. Here, the question of whether this increased sucrose influx mirrors a regulation of sucrose transporters in xylem tissue was tested. A putative sucrose transporter cDNA ( JrSUT1: Juglans regia sucrose transporter 1) was isolated. Over the autumn-winter period, JrSUT1 transcripts and respective proteins were present in xylem parenchyma cells and highly detected when samplings were performed shortly after a freeze-thaw cycle. This up-regulation of JrSUT1 level was confirmed in controlled conditions and was not obtained in bark. Immunolocalization studies showed that JrSUT1 and plasma membrane H + + + + -ATPase (JrAHA) were colocalized to vessel-associated cells (VACs), which control solute exchanges between parenchyma cells and xylem vessels. We propose that JrSUT1 could be involved in the retrieval of sucrose from xylem vessel. All these data are discussed with respect to the winter biology of the walnut tree.

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“…If the tree's metabolism alters the proton concentration in the positive annulus in any one cross-section of xylem then Coulomb forces will tend to ensure that negative charges are drawn into or repelled from the core region in order to maintain neutrality in the cross-section as a whole. Metabolic proton transfer, possibly via the xylem VAC and phloem companion cells as demonstrated by Fromard et al (1995), would then modify the electrical force on each element of sap. Local control of nutrient delivery mediated by proton transfer then becomes a possibility.…”

Section: Corollaries Of the Postulated Electrical Force Mechanismmentioning

confidence: 99%

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2013

WATER

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Control of Vascular Sap pH by the Vessel-Associated Cells in Woody Species (Physiological and Immunological Studies)

Cited by 63 publications

References 25 publications

Diurnal and seasonal changes of leaf lamina hydraulic conductance in bur oak (Quercus macrocarpa) and trembling aspen (Populus tremuloides)

Diurnal and seasonal changes of leaf lamina hydraulic conductance in bur oak (Quercus macrocarpa) and trembling aspen (Populus tremuloides)

JrSUT1, a putative xylem sucrose transporter, could mediate sucrose influx into xylem parenchyma cells and be up‐regulated by freeze–thaw cycles over the autumn–winter period in walnut tree (Juglans regia L.)

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