scholarly journals 198 EVALUATION OF DROUGHT TOLERANCE OF Fragaria chiloensis CLONES WITH POTENTIAL AS LOW-MAINTENANCE ORNAMENTAL GROUNDCOVERS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 457e-457
Author(s):  
Ann Marie VanDerZanden ◽  
J. Scott Cameron
Keyword(s):  
Gas Exchange ◽  
Drought Tolerance ◽  
Control Group ◽  
Total Biomass ◽  
Stress Cycle ◽  
Chl A ◽  
Water Potentials ◽  
Fragaria Chiloensis ◽  
Fourth Derivative ◽  
Recovery Cycles

Fragaria chiloensis (Linnaeus) Is a viable. low maintenance alternative to groundcovers currently available in the ornamental landscape industry. There is considerable genetic variability within this specks for leaf morphology, growth and flowering habits as well as drought tolerance. Clones collected from 11 coastal sites in CA and OR were compared for drought tolerance after two Imposed water stress\recovery cycles. Predawn water potential, gas exchange, chlorophyll (chl) content, fourth derivative spectroscopy, carbon isotope discrimination, and total biomass production were evaluated and significant clonal differences were observed. Predawn water potentials after the first stress cycle ranged from -35.0 MPa to -6.5 MPa. Clones I05, DNT and G19 had highest predawn water potentials and gas exchange rates after both stress cycles. In the control group, I05 and DNT had higher levels of chl a, chl b, total chl and chl a\b. After the first stress cycle, clones DNT and I05 had the highest chl a\b ratio, however, after the second stress event there were no differences In any chl parameters. Varying adaptive abilities observed may suggest differential use in the landscape.

The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 540a-540
Author(s):  
K.J. Prevete ◽  
R.T. Fernandez
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Gas Analysis ◽  
Herbaceous Perennials ◽  
Effects Of Drought ◽  
Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

Colloidal gold particles as a new in vivo marker of early acute lung injury

2004 ◽  
Vol 287 (4) ◽  
pp. L867-L878 ◽  
Author(s):  
Kai Heckel ◽  
Rainer Kiefmann ◽  
Martina Dörger ◽  
Mechthild Stoeckelhuber ◽  
Alwin E. Goetz
Keyword(s):  
Electron Microscopy ◽  
Acute Lung Injury ◽  
Gas Exchange ◽  
Lung Injury ◽  
Colloidal Gold ◽  
Microvascular Permeability ◽  
Arterial Oxygen ◽  
Control Group ◽  
Gold Particles

Permeability of the endothelial barrier to large molecules plays a pivotal role in the manifestation of early acute lung injury. We present a novel and sensitive technique that brings microanatomical visualization and quantification of microvascular permeability in line. White New Zealand rabbits were anesthetized and ventilated mechanically. Rabbit serum albumin (RSA) was labeled with colloidal gold particles. We quantified macromolecular leakage of gold-labeled RSA and thickening of the gas exchange distance by electron microscopy, taking into account morphology of microvessels. The control group receiving a saline solution represented a normal gas exchange barrier without extravasation of gold-labeled albumin. Infusion of lipopolysaccharide (LPS) resulted in a significant displacement of gold-labeled albumin into pulmonary cells, the lung interstitium, and even the alveolar space. Correspondingly, intravital fluorescence microscopy and digital image analysis indicated thickening of width of alveolar septa. The findings were accompanied by a deterioration of alveolo-arterial oxygen difference, whereas wet/dry ratio and albumin concentration in the bronchoalveolar lavage fluid failed to detect that early stage of pulmonary edema. Inhibition of the nuclear enzyme poly(ADP-ribose) synthetase by 3-aminobenzamide prevented LPS-induced microvascular injury. To summarize: colloidal gold particles visualized by standard electron microscopy are a new and very sensitive in vivo marker of microvascular permeability in early acute lung injury. This technique enabling detailed microanatomical and quantitative pathophysiological characterization of edema formation can form the basis for evaluating novel treatment strategies against acute lung injury.

scholarly journals Surfactant control of gas transfer velocity along an offshore coastal transect: results from a laboratory gas exchange tank

2016 ◽  
Vol 13 (13) ◽  
pp. 3981-3989 ◽  
Author(s):  
R. Pereira ◽  
K. Schneider-Zapp ◽  
R. C. Upstill-Goddard
Keyword(s):  
Organic Matter ◽  
Gas Exchange ◽  
Trace Gas ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Chl A ◽  
Gas Transfer Velocity ◽  
Biogeochemical Models ◽  
Sea Surface Microlayer ◽  
Laboratory Water

Abstract. Understanding the physical and biogeochemical controls of air–sea gas exchange is necessary for establishing biogeochemical models for predicting regional- and global-scale trace gas fluxes and feedbacks. To this end we report the results of experiments designed to constrain the effect of surfactants in the sea surface microlayer (SML) on the gas transfer velocity (kw; cm h−1), seasonally (2012–2013) along a 20 km coastal transect (North East UK). We measured total surfactant activity (SA), chromophoric dissolved organic matter (CDOM) and chlorophyll a (Chl a) in the SML and in sub-surface water (SSW) and we evaluated corresponding kw values using a custom-designed air–sea gas exchange tank. Temporal SA variability exceeded its spatial variability. Overall, SA varied 5-fold between all samples (0.08 to 0.38 mg L−1 T-X-100), being highest in the SML during summer. SML SA enrichment factors (EFs) relative to SSW were  ∼  1.0 to 1.9, except for two values (0.75; 0.89: February 2013). The range in corresponding k660 (kw for CO2 in seawater at 20 °C) was 6.8 to 22.0 cm h−1. The film factor R660 (the ratio of k660 for seawater to k660 for “clean”, i.e. surfactant-free, laboratory water) was strongly correlated with SML SA (r ≥ 0.70, p ≤ 0.002, each n = 16). High SML SA typically corresponded to k660 suppressions  ∼  14 to 51 % relative to clean laboratory water, highlighting strong spatiotemporal gradients in gas exchange due to varying surfactant in these coastal waters. Such variability should be taken account of when evaluating marine trace gas sources and sinks. Total CDOM absorbance (250 to 450 nm), the CDOM spectral slope ratio (SR = S275 − 295∕S350 − 400), the 250 : 365 nm CDOM absorption ratio (E2 : E3), and Chl a all indicated spatial and temporal signals in the quantity and composition of organic matter in the SML and SSW. This prompts us to hypothesise that spatiotemporal variation in R660 and its relationship with SA is a consequence of compositional differences in the surfactant fraction of the SML DOM pool that warrants further investigation.

scholarly journals Physiological Performance of Pyrus pyraster L. (Burgsd.) and Sorbus torminalis (L.) Crantz Seedlings under Drought Treatment

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1496
Author(s):  
Viera Paganová ◽  
Marek Hus ◽  
Zuzana Jureková
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Water Scarcity ◽  
Prolonged Exposure ◽  
Leaf Gas Exchange ◽  
Total Biomass ◽  
Drought Treatment ◽  
Water Regimes ◽  
Sorbus Torminalis ◽  
Pyrus Pyraster

In this study, seedlings of Pyrus pyraster and Sorbus torminalis were grown for 60 days in the regulated environment of a growth chamber under different water regimes. The measured indicators were the growth and distribution of mass to organs, total biomass, root to shoot mass ratio (R:S), and gas exchange parameters (gs, E, An, and water use efficiency (WUE)). The amount of total biomass was negatively affected by drought. Differences between species were confirmed only for the dry matter of the leaves. P. pyraster maintained the ratio of the mass distribution between belowground and aboveground organs in both variants of the water regime. S. torminalis created more root length for a given dry-mass under drought treatment, but its R:S was lower compared to P. pyraster. The water potential of the leaves (Ψwl) was affected by substrate saturation and interspecific differences. P. pyraster had a demonstrably higher water potential and maintained this difference even after prolonged exposure to drought. After 30 days of different water regimes, Pyrus maintained higher values of gs, An, and E in control and drought treatments, but over a longer period of drought (after 50 days), the differences between species were equalized. The changes of the leaf gas exchange for Pyrus were accompanied by a significant increase in WUE, which was most pronounced on the 40th day of the experiment. A significant and strong relationship between WUE and gs was demonstrated. The results confirmed the different physiological performances of seedlings of tree species and the different mechanisms of their response to water scarcity during drought treatment. P. pyraster presented more acclimation traits, which allowed this taxon to exhibit better performance over a longer period of water scarcity.

Pulmonary vascular effects of furosemide on gas exchange in pulmonary edema

1984 ◽  
Vol 57 (1) ◽  
pp. 160-167 ◽  
Author(s):  
J. Ali ◽  
L. D. Wood
Keyword(s):  
Body Weight ◽  
Oleic Acid ◽  
Gas Exchange ◽  
Pulmonary Edema ◽  
Venous Blood ◽  
Control Group ◽  
Pulmonary Perfusion ◽  
Vascular Effects

To test the hypothesis that pulmonary vasoactivity of furosemide redistributes blood away from edematous lung, thus improving gas exchange, we studied two groups of 10 dogs each with unilobar oleic acid edema, treating one group with 1 mg/kg furosemide 2 h after the oleic acid. Pulmonary perfusion distribution was determined with radio microspheres. Shunts of the injured lobe, measured from O2 contents of lower lobar pulmonary venous blood, increased significantly (P less than 0.05) at 2 h after injury in both groups. Within 0.5 h after furosemide the lobar shunt decreased in the treated animals from 40.1 +/- 20.6 to 28.6 +/- 20.1% and increased from 21.4 +/- 14.0 to 53.8 +/- 26.9% in the control group (P less than 0.05). Mean fractional lobar perfusion to the injured lobe increased from 18.2 +/- 4.8 to 21.6 +/- 6.4% (P less than 0.05) in the furosemide group but decreased from 20.1 +/- 3.5 to 16.1 +/- 4.4% (P less than 0.05) in the controls. Wet lung-to-body weight ratios of the edematous lobes did not differ between the two groups. Our data suggest the possibility that, before decreasing edema, furosemide improved shunt through pulmonary vascular effects by preferential perfusion of nonflooded alveolar units.

scholarly journals Prevalence of lung structure abnormalities in patients with acromegaly and their relationship with gas exchange: cross-sectional analytical study with a control group

2015 ◽  
Vol 133 (5) ◽  
pp. 394-400 ◽  
Author(s):  
Marcelo Palmeira Rodrigues ◽  
Luciana Ansaneli Naves ◽  
Carlos Alberto Viegas ◽  
Cesar Augusto Melo-Silva ◽  
Wagner Diniz de Paula ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Analytical Study ◽  
University Hospital ◽  
Control Group ◽  
Chronic Obstructive ◽  
Structural Factors ◽  
Serum Growth Hormone ◽  
Cross Sectional ◽  
Arterial Blood ◽  
Lung Structure

CONTEXT AND OBJECTIVE: Different functional respiratory alterations have been described in acromegaly, but their relationship with pulmonary tissue abnormalities is unknown. The objective of this study was to observe possible changes in lung structure and explain their relationship with gas exchange abnormalities. DESIGN AND SETTING: Cross-sectional analytical study with a control group, conducted at a university hospital. METHODS: The study included 36 patients with acromegaly and 24 controls who were all assessed through high-resolution computed tomography of the thorax (CT). Arterial blood gas, effort oximetry and serum growth hormone (GH) and insulin-like growth factor I (IGF-1) were also assessed in the patients with acromegaly. RESULTS: The abnormalities found in the CT scan were not statistically different between the acromegaly and control groups: mild cylindrical bronchiectasis (P = 0.59), linear opacity (P = 0.29), nodular opacity (P = 0.28), increased attenuation (frosted glass; P = 0.48) and decreased attenuation (emphysema; P = 0.32). Radiographic abnormalities were not associated with serum GH and IGF-1. Hypoxemia was present in seven patients; however, in six of them, the hypoxemia could be explained by underlying clinical conditions other than acromegaly: chronic obstructive pulmonary disease in two, obesity in two, bronchial infection in one and asthma in one. CONCLUSION: No changes in lung structure were detected through thorax tomography in comparison with the control subjects. The functional respiratory alterations found were largely explained by alternative diagnoses or had subclinical manifestations, without any plausible relationship with lung structural factors.

Gas exchange kinetics in obese adolescents. Inferences on exercise tolerance and prescription

2010 ◽  
Vol 299 (5) ◽  
pp. R1298-R1305 ◽  
Author(s):  
Desy Salvadego ◽  
Stefano Lazzer ◽  
Carlo Busti ◽  
Raffaela Galli ◽  
Fiorenza Agosti ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Gas Exchange ◽  
Oxidative Metabolism ◽  
Exercise Tolerance ◽  
Slow Component ◽  
Control Group ◽  
Time To Exhaustion ◽  
Functional Evaluation ◽  
Obese Adolescents ◽  
Fundamental Component

A functional evaluation of skeletal muscle oxidative metabolism was performed in a group of obese adolescents (OB). The various components of pulmonary O2 uptake (V̇o2) kinetics were evaluated during 10-min constant-load exercises (CLE) on a cycloergometer at different percentages of V̇o2max. The relationships of these components with the gas exchange threshold (GET) were determined. Fourteen male OB [age 16.5 ± 1.0 (SD) yr, body mass index 34.5 ± 3.1 kg·m−2] and 13 normal-weight, age-matched nonathletic male volunteers (control group) were studied. The time-constant (τf) of the fundamental component and the presence, pattern, and relative amplitude of the slow component of V̇o2 kinetics were determined at 40, 60, and 80% of V̇o2max, previously estimated during an incremental test. V̇o2max (l/min) was similar in the two groups. GET was lower in OB (55.7 ± 6.7% of V̇o2max) than in control (65.1 ± 5.2%) groups. The τf was higher in OB subjects, indicating a slower fundamental component. At CLE 60% (above GET in OB subjects, below GET in control subjects) a slow component was observed in nine out of fourteen OB subjects, but none in the control group. All subjects developed a slow component at CLE 80% (above GET in both OB and control). Twelve OB subjects did not complete the 10-min CLE 80% due to voluntary exhaustion. In nine OB subjects, the slow component was characterized by a linear increase in V̇o2 as a function of time. The slope of this increase was inversely related to the time to exhaustion. The above findings should negatively affect exercise tolerance in obese adolescents and suggest an impairment of skeletal muscle oxidative metabolism. Also in obese adolescents, exercise evaluation and prescription at submaximal loads should be done with respect to GET and not at a given percentage of V̇o2max.

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