scholarly journals A mutation that eliminates bundle sheath extensions reduces leaf hydraulic conductance, stomatal conductance and assimilation rates in tomato (Solanum lycopersicum)

2014 ◽  
Vol 205 (2) ◽  
pp. 618-626 ◽  
Author(s):  
Agustin Zsögön ◽  
Ana Clarissa Alves Negrini ◽  
Lázaro Eustáquio Pereira Peres ◽  
Hoa Thi Nguyen ◽  
Marilyn C. Ball
Keyword(s):  
Stomatal Conductance ◽  
Solanum Lycopersicum ◽  
Hydraulic Conductance ◽  
Bundle Sheath ◽  
Leaf Hydraulic Conductance

scholarly journals Arabidopsis leaf hydraulic conductance is regulated by xylem-sap pH, controlled, in turn, by a P-type H+-ATPase of vascular bundle sheath cells

2017 ◽  
Author(s):  
Yael Grunwald ◽  
Noa Wigoda ◽  
Nir Sade ◽  
Adi Yaaran ◽  
Tanmayee Torne ◽  
...  
Keyword(s):  
Proton Pump ◽  
Vascular Bundle ◽  
Xylem Sap ◽  
Hydraulic Conductance ◽  
Bundle Sheath ◽  
List Type ◽  
Mesophyll Cells ◽  
Leaf Hydraulic Conductance ◽  
Bundle Sheath Cells ◽  
Sheath Cells

AbstractThe leaf vascular bundle sheath cells (BSCs) that tightly envelop the leaf veins, are a selective and dynamic barrier to xylem-sap water and solutes radially entering the mesophyll cells. Under normal conditions, xylem-sap pH of <6 is presumably important for driving and regulating the transmembranal solute transport. Having discovered recently a differentially high expression of a BSCs proton pump, AHA2, we now test the hypothesis that it regulates this pH and leaf radial water fluxes.We monitored the xylem-sap pH in the veins of detached leaves of WT Arabidopsis, AHA mutants, and aha2 mutants complemented with AHA2 gene solely in BSCs. We tested an AHA inhibitor and stimulator, and different pH buffers. We monitored their impact on the xylem-sap pH and the whole leaf hydraulic conductance (Kleaf), and the effect of pH on the water osmotic permeability (Pf) of isolated BSCs protoplasts.Our results demonstrated that AHA2 is necessary for xylem-sap acidification, and in turn, for elevating Kleaf. Conversely, knocking out AHA2 alkalinized the xylem-sap. Also, elevating xylem sap pH to 7.5 reduced Kleaf and elevating external pH to 7.5 decreased the BSCs Pf.All these demonstrate a causative link between AHA2 activity in BSCs and leaf radial water conductance.One-sentence summaryBundle-sheath cells can control the leaf hydraulic conductance by proton-pump-regulated xylem sap pH

Water transport from stem to stomata: the coordination of hydraulic and gas exchange traits across 33 subtropical woody species

2019 ◽  
Vol 39 (10) ◽  
pp. 1665-1674 ◽  
Author(s):  
Xiaorong Liu ◽  
Hui Liu ◽  
Sean M Gleason ◽  
Guillermo Goldstein ◽  
Shidan Zhu ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Transport ◽  
Explanatory Power ◽  
Woody Species ◽  
Hydraulic Conductance ◽  
Co2 Assimilation ◽  
Leaf Hydraulic Conductance ◽  
Net Co2 Assimilation ◽  
Leaf Tissues

Abstract Coordination between sapwood-specific hydraulic conductivity (Ks) and stomatal conductance (gs) has been identified in previous studies; however, coordination between leaf hydraulic conductance (Kleaf) and gs, as well as between Kleaf and Ks is not always consistent. This suggests that there is a need to improve our understanding of the coordination among hydraulic and gas exchange traits. In this study, hydraulic traits (e.g., Ks and Kleaf) and gas exchange traits, including gs, transpiration (E) and net CO2 assimilation (Aarea), were measured across 33 co-occurring subtropical woody species. Kleaf was divided into two components: leaf hydraulic conductance inside the xylem (Kleaf-x) and outside the xylem (Kleaf-ox). We found that both Kleaf-x and Kleaf-ox were coordinated with gs and E, but the correlations between Kleaf-ox and gs (or E) were substantially weaker, and that Ks was coordinated with Kleaf-x, but not with Kleaf-ox. In addition, we found that Ks, Kleaf-x and Kleaf-ox together explained 63% of the variation in gs and 42% of the variation in Aarea across species, with Ks contributing the largest proportion of explanatory power, whereas Kleaf-ox contributed the least explanatory power. Our results demonstrate that the coordination between leaf water transport and gas exchange, as well as the hydraulic linkage between leaf and stem, were weakened by Kleaf-ox. This highlights the possibility that water transport efficiencies of stem and leaf xylem, rather than that of leaf tissues outside the xylem, are important determinants of stomatal conductance and photosynthetic capacity across species.

scholarly journals Role of leaf hydraulic conductance in the regulation of stomatal conductance in almond and olive in response to water stress

2016 ◽  
Vol 36 (6) ◽  
pp. 725-735 ◽  
Author(s):  
Virginia Hernandez-Santana ◽  
Celia M. Rodriguez-Dominguez ◽  
J. Enrique Fernández ◽  
Antonio Diaz-Espejo
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Hydraulic Conductance ◽  
Leaf Hydraulic Conductance ◽  
Response To Water
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