scholarly journals Amelioration of Chilling-Induced Water Stress by Abscisic Acid-Induced Changes in Root Hydraulic Conductance

1984 ◽  
Vol 74 (1) ◽  
pp. 81-83 ◽  
Author(s):  
Albert H. Markhart
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Induced Changes

scholarly journals Concentrated Exogenous Abscisic Acid Drenches Reduce Root Hydraulic Conductance and Cause Wilting in Tomato

HortScience ◽  
2011 ◽  
Vol 46 (12) ◽  
pp. 1640-1645 ◽  
Author(s):  
Manuel G. Astacio ◽  
Marc W. van Iersel
Keyword(s):  
Abscisic Acid ◽  
Water Transport ◽  
Water Flux ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Fresh Weight ◽  
Cumulative Volume ◽  
Effective Transport ◽  
Relative Water ◽  
Root Conductance

Previous work has shown that exogenous abscisic acid (ABA) applications can reduce transpiration, delay wilting, and thereby extend the shelf life of unwatered plants. Paradoxically, we have seen that drenches with concentrated ABA solutions may actually induce wilting. These wilting symptoms occur despite the presence of ample water in the substrate, suggesting that ABA may interfere with the ability of roots to take up water. Our objective was to develop a better understanding of this wilting effect using tomato (Solanum lycopersicum) as a model. In the first study, ABA drenches (125–2000 mg·L−1) reduced transpiration and water use compared with the control plants, yet the relative water content (RWC) of the leaves of ABA-treated plants was lower than that of control plants at 24 h after the ABA drench. Control plants had a leaf RWC of 97%, whereas plants treated ABA had a RWC of 57% to 62%. ABA concentrations of 500 mg·L−1 or higher caused the plants to wilt within 24 h despite the presence of ample water in the substrate. Leaf ABA concentrations 24 h after the ABA application ranged from 2.6 (control) to 62.6 nmol·g−1 fresh weight (FW) in the 2000-mg·L−1 ABA treatment, indicating effective transport of ABA from the roots to the leaves. The reduced leaf RWC suggests that ABA drenches are limiting water transport through the roots to the leaves. The effects of ABA on the hydraulic conductance of the roots and stems of tomatoes were quantified to determine if ABA drenches limit water transport through the roots. The cumulative volume of water conducted by the root systems during a 4-day period ranged from 36.7 mL in the control treatments to 8.1 mL in roots systems drenched with 1000 mg·L−1 ABA, a reduction of 78%. When the conductance study was repeated using decapitated roots and excised stems, root water flux was again reduced by ABA, but water flux through internodal stem sections did not show an ABA effect. Results suggest that ABA-induced wilting is caused by a reduction in root conductance and we hypothesize that ABA affects aquaporins in the roots, limiting water uptake.

Mercurial inhibition of root hydraulic conductance in Vitis spp. rootstocks under water stress

2008 ◽  
Vol 63 (1-3) ◽  
pp. 178-182 ◽  
Author(s):  
Claudio Lovisolo ◽  
Sara Tramontini ◽  
Jaume Flexas ◽  
Andrea Schubert
Keyword(s):  
Water Stress ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Vitis Spp

Changes in Water Relations, Water Flux, and Root Exudate Abscisic Acid Content With Cold Acclimation of Pinus sylvestris L

1984 ◽  
Vol 11 (5) ◽  
pp. 431 ◽  
Author(s):  
B Smit-Spinks ◽  
BT Swanson ◽  
AH Iii Markhart
Keyword(s):  
Abscisic Acid ◽  
Water Content ◽  
Cold Acclimation ◽  
Transpiration Rate ◽  
Relative Water Content ◽  
Root Exudate ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Xylem Pressure ◽  
Relative Water

Scotch pine seedlings (Pinus sylvestris L.) were subjected to 6 week photoperiod and thermoperiod treatments to induce different levels of cold acclimation. The water content, relative water content, xylem pressure potential, transpiration rate, root hydraulic conductance, and abscisic acid (ABA) content of root exudate were then measured. Water content decreased in woody stems and needles with cold acclimation but not in the roots and green stems. There was a close correlation between relative water content and water content of woody stems and needles as well as a decrease in xylem pressure potentials of hardy needles, indicating that the reduction in water content was at least partially due to increased water deficit. The increased water deficit was not caused by increased water loss since transpiration rates decreased in hardy shoots. Water uptake was reduced by decreased root hydraulic conductance which could account for the shoot water deficits. Root hydraulic conductance and transpiration rate returned to non-acclimated levels after warm temperature exposure. ABA levels were highest in the root exudate collected in the morning from non-acclimated plants.

scholarly journals Fine Root Hydraulic Conductance Is Related to Post-transplant Recovery of Two Quercus Tree Species

2014 ◽  
Vol 139 (6) ◽  
pp. 649-656 ◽  
Author(s):  
Jingjing Yin ◽  
Nina L. Bassuk ◽  
Madeline W. Olberg ◽  
Taryn L. Bauerle
Keyword(s):  
Water Stress ◽  
Fine Roots ◽  
Fine Root ◽  
Hydraulic Conductance ◽  
Root Pruning ◽  
Root Hydraulic Conductance ◽  
Xylem Water Potential ◽  
Post Transplant ◽  
Transplant Shock ◽  
Mild Water Stress

In our study, we investigated whether root hydraulic conductance is related to post-transplant recovery. We used two Quercus species that differ in their transplant ability, Q. bicolor and Q. macrocarpa. Q. bicolor easily survives transplanting, whereas Q. macrocarpa often does not. We compared root hydraulic conductance after transplanting between control (without root pruning) and root-pruned, 1-year-old, small-caliper trees. We also examined the effects of transplant timing on post-transplant recovery of large-caliper trees. Hydraulic conductance in fine roots was correlated with recovery of the two Quercus species after transplanting. Six months after transplanting, small-caliper Q. bicolor trees had similar specific hydraulic conductance (KS) in fine roots compared with the KS before root-pruning, whereas fine root KS in small-caliper Q. macrocarpa trees decreased. Lower pre-dawn and midday xylem water potential in root-pruned Q. macrocarpa 6 weeks after transplanting indicates that root-pruned Q. macrocarpa experienced transplanting-induced water stress. For large-caliper trees, all Q. macrocarpa trees exhibited typical symptoms of transplant shock regardless of transplant timing, which was the result of higher vulnerability to mild water stress compared with Q. bicolor, resulting in a large reduction in fine root KS. Fine root KS in spring-transplanted Q. bicolor trees was much higher than that in fall-transplanted trees, implying spring transplanting is optimal for Q. bicolor. Other intrinsic characteristics of the species should be considered in the future when making better decisions on transplant timing such as xylem anatomy, carbon storage, rhizosphere conditions, and plant growth.

scholarly journals The Grapevine Root-Specific Aquaporin VvPIP2;4N Controls Root Hydraulic Conductance and Leaf Gas Exchange under Well-Watered Conditions But Not under Water Stress

2012 ◽  
Vol 160 (2) ◽  
pp. 965-977 ◽  
Author(s):  
Irene Perrone ◽  
Giorgio Gambino ◽  
Walter Chitarra ◽  
Marco Vitali ◽  
Chiara Pagliarani ◽  
...  
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Leaf Gas Exchange ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance
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