scholarly journals Rapid and long-term effects of water deficit on gas exchange and hydraulic conductance of silver birch trees grown under varying atmospheric humidity

2014 ◽  
Vol 14 (1) ◽  
pp. 72 ◽  
Author(s):  
Arne Sellin ◽  
Aigar Niglas ◽  
Eele Õunapuu-Pikas ◽  
Priit Kupper
Keyword(s):  
Gas Exchange ◽  
Water Deficit ◽  
Hydraulic Conductance ◽  
Silver Birch ◽  
Long Term Effects ◽  
Atmospheric Humidity ◽  
Birch Trees

scholarly journals Intrapulmonary shunting and pulmonary gas exchange during normoxic and hypoxic exercise in healthy humans

2008 ◽  
Vol 104 (5) ◽  
pp. 1418-1425 ◽  
Author(s):  
Andrew T. Lovering ◽  
Lee M. Romer ◽  
Hans C. Haverkamp ◽  
David F. Pegelow ◽  
John S. Hokanson ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Contrast Echocardiography ◽  
Pulmonary Gas Exchange ◽  
Pulmonary Vasculature ◽  
Long Term Effects ◽  
Arteriovenous Shunting ◽  
Healthy Humans ◽  
Intrapulmonary Shunting ◽  
Exercise Induced

Exercise-induced intrapulmonary arteriovenous shunting, as detected by saline contrast echocardiography, has been demonstrated in healthy humans. We have previously suggested that increases in both pulmonary pressures and blood flow associated with exercise are responsible for opening these intrapulmonary arteriovenous pathways. In the present study, we hypothesized that, although cardiac output and pulmonary pressures would be higher in hypoxia, the potent pulmonary vasoconstrictor effect of hypoxia would actually attenuate exercise-induced intrapulmonary shunting. Using saline contrast echocardiography, we examined nine healthy men during incremental (65 W + 30 W/2 min) cycle exercise to exhaustion in normoxia and hypoxia (fraction of inspired O2 = 0.12). Contrast injections were made into a peripheral vein at rest and during exercise and recovery (3–5 min postexercise) with pulmonary gas exchange measured simultaneously. At rest, no subject demonstrated intrapulmonary shunting in normoxia [arterial Po2 (PaO2) = 98 ± 10 Torr], whereas in hypoxia (PaO2 = 47 ± 5 Torr), intrapulmonary shunting developed in 3/9 subjects. During exercise, ∼90% (8/9) of the subjects shunted during normoxia, whereas all subjects shunted during hypoxia. Four of the nine subjects shunted at a lower workload in hypoxia. Furthermore, all subjects continued to shunt at 3 min, and five subjects shunted at 5 min postexercise in hypoxia. Hypoxia has acute effects by inducing intrapulmonary arteriovenous shunt pathways at rest and during exercise and has long-term effects by maintaining patency of these vessels during recovery. Whether oxygen tension specifically regulates these novel pathways or opens them indirectly via effects on the conventional pulmonary vasculature remains unclear.

scholarly journals Does water deficit negatively impact wine grape yield over the long term?

2020 ◽  
Author(s):  
Alexander D. Levin ◽  
Alain Deloire ◽  
Gregory A. Gambetta
Keyword(s):  
Water Deficit ◽  
Red Wine ◽  
Reproductive Development ◽  
Wine Grape ◽  
Long Term Effects ◽  
Current Season ◽  
Water Deficits ◽  
Woody Perennial ◽  
Grape Yield

Like many other woody perennial crops, grapevine reproductive development occurs over a two-year cycle. Given that water deficits are commonplace in viticulture, especially for red wine grape production, this raises questions about how water deficit in the current season could potentially impact yields the following year. This article will focus on the long-term effects of water deficits on grapevine yield.

WATER RELATIONS, GAS EXCHANGE, AND NUTRIENT RESPONSE TO A LONG TERM CONSTANT WATER DEFICIT

Soil Science ◽  
1992 ◽  
Vol 153 (6) ◽  
pp. 442-451 ◽  
Author(s):  
WADE L. BERRY ◽  
GUILLERMO GOLDSTEIN ◽  
THOMAS W. DRESCHEL ◽  
RAYMOND M. WHEELER ◽  
JOHN C. SAGER ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Deficit ◽  
Water Relations ◽  
Nutrient Response

scholarly journals (451) Acclimation to Long-term Water Deficit Stress in Four Birch Taxa (Betula L.): Water Relations and Gas Exchange

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1035E-1036
Author(s):  
Mengmeng Gu ◽  
Curt R. Rom ◽  
James A. Robbins
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Potential ◽  
Water Deficit ◽  
Water Deficit Stress ◽  
Water Deficits ◽  
Daily Water ◽  
Use Efficiency ◽  
Exchange Data

Four birch taxa, Betulaalleghaniensis, B. davurica, B. nigra `Heritage', and B. papyrifera, were grown in a greenhouse and exposed to water deficit stress for 35 days. Daily water was withheld from the plants until the combined weight of each container and the plant was reduced to 40% of the control. Supplemental water was supplied to each container to maintain 40% of the initial combined weight. Predawn water potential, gas exchange, and abscised leaf area were measured daily during the first week and at 3-day intervals after the first week. Predawn water potential dropped to lowest value before the containers were rehydrated and remained low throughout the treatment period. Net CO2 assimilation (A), stomatal conductance (gs) and evapotranspiration (Et) of all taxa decreased significantly during the first week of water deficits. Changes in A and Et varied among taxa after the first week of water deficits. Water use efficiency (WUE = A/Et) of four birch taxa decreased to significant lower values than control in the first week that water was withheld, and then increased to significantly higher values than control. Gas exchange data were fit into 2- or 3-segmented linear model. The type and shape of the models, and the joint of each segment gave an indication of how the gas exchange responded to the long-term water deficit stress. At the end of the water deficit treatment, B. papyrifera had abscised most of its leaves and maintained a high A, while B. alleghaniensis maintained more leaves on the tree, but had a relatively low A.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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