Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 16 of 16 for “"open top chambers"”.
-
Seasonal effects of elevated carbon dioxide, competition, and water stress on gas exchange and growth of loblolly pine and sweetgum grown in open-top chambers
… miniature stands at 7.6-cm spacings outdoors in open-top chambers (4.6 m in diameter and 3.5 m tall) for 16 months. Treatments consisted of ambient- and elevated-CO₂ , drought-stressed and well-watered, and stand type (monoculture and 50:50 replacement mixture). Gas exchange was measured monthly, …
-
Assessment of air pollution impacts on vegetation in South Africa
… a biomonitoring network station (plant cages), open-top chambers (filtered and unfiltered), as well as in open plots. The responses of plants grown under these different conditions were compared. During both the winter and summer seasons, ambient fluoride concentrations were estimated to be …
-
Effects of 11 Years of CO2 Enrichment on Root Biomass and Spatial Distribution in a Florida Scrub-Oak Ecosystem
… to elevated atmospheric CO<sub>2</sub> in open-top chambers from 1996-2007. Minirhizotrons and ground-penetrating radar (GPR) were used to measure fine root (< 2 mm diameter) and coarse root (> 5 mm diameter) biomass, respectively. After 11 years of CO<sub>2</sub> enrichment, there was a …
-
Effects of Elevated Atmospheric CO2 on Root Dynamics, Biomass and Architecture in a Scrub-Oak Ecosystem at Kennedy Space Center, Florida
… in a fire dominated scrub-oak ecosystem. Open-top chambers have been exposed to elevated atmospheric CO<sub>2</sub> for the past eleven years at Kennedy Space Center, Florida. No significant sustained CO<sub>2</sub> treatment effects were observed in fine root length density, due to root …
-
Ecophysiological responses of Themeda triandra Forsk. and other Southern African Câ‚„ grass species to increases in atmospheric COâ‚‚ concentrations
… tufts for periods of at least four months in open-top chambers in a greenhouse under either ambient (360 Ilmol mor1 ) or elevated (650-700 Ilmol mor1 ) CO2 concentration. Both inter- and intra-specific variability in the CO2-response were studied, under different seasonal temperature regimes. …
-
Ozone effects on red oak root dynamics
… ozone (subambient, ambient, and 2X ambient) in open-top chambers. After two seasons of exposure, 2X ozone (0.082 ppm 7hr-mean conc.) reduced mature- tree cumulative net fine-root production and turnover by 31 and 41 %, respectively, relative to ambient ozone (0.042 ppm 7hr-mean conc.). For the …
-
Effects of Elevated Atmospheric CO₂ on Scrub-Oak Root Carbon Pools and Soil Microbial Processes
… been elevated to twice ambient since 1996 in open top chambers. There were eight replicates of ambient CO<sub>2</sub> chambers and eight replicates of twice-ambient CO<sub>2 </sub>levels. The chambers were blocked according to the vegetation present at the beginning of the study and the site …
-
Effects of Elevated Atmospheric CO2 on Root Growth, Turnover and Decomposition in a Scrub Oak Ecosystem
… on fine root growth and decomposition using open top chambers with both ambient and elevated (700 PPM) CO<sub>2</sub> treatments in an oak-palmetto scrub ecosystem at Kennedy Space Center, Florida. Minirhizotron tubes were installed in each elevated and control chamber to allow observation of …
-
Comparative study of an antioxidant defense mechanism in genotypes of eastern white pine which show differential foliar characteristics
… ambient air compared to charcoal-filtered air in open-top chambers. Cloned sensitive trees had similar GSH concentrations when exposed to different chamber treatments. One-year-old needles always had lower ratios of ascorbate/ dehydroascorbate, ascorbate/α-tocopherol and GSH/GSSG than current year …
-
Characterizing the Respiration of Stems and Roots of Three Hardwood Tree Species in the Great Smoky Mountains
… study, BC and RM seedlings were fumigated in open-top chambers with sub-ambient, ambient and twice-ambient levels of ozone. The twice-ambient treatment reduced stem CER in BC by 50% (p=0.05) in July, but there was no treatment effect in September or in RM. Ozone reduced root/shoot ratio and …
-
Air pollution impacts to agricultural crops
… (Beta vulgaris) and onion (Allium cepa) in open-top chambers in UK showed that high O3 concentrations can affect both species in terms of visible injury and growth. However, onion is at greater risk in the field as it is a summer crop and is likely to be exposed to high O3 concentrations, …
-
Effect of O3 fumigation on photosynthesis and growth of quinoa and its interaction with drought and elevated CO2
… O3, 700 ppm CO2 and 700 ppm CO2 + 80 ppb O3 in open-top chambers. Ozone exposure-thresholds for damage, elevated CO2 and water stress effects were assessed by prompt chlorophyll a fluorescence induction kinetics. Chlorophyll a fluorescence data for both drought-induced and ozone treated plants …
-
The influence of drought, and other abiotic factors on tree water use in a temperate remnant forest
… to measure rates of sap flow through trees; (b) open-top chambers to measure understorey and soil evapotranspiration; (c) application of the Penman-Monteith equation to estimate canopy conductance and transpiration rates; (d) two methods to scale spatially from measurements of individual trees to …
-
Experimental warming of subarctic biocrust: Temporal responses of soil respiration and plant community
… experiment where warming was induced with open-top chambers (OTCs). Soil respiration, temperature, soil water content, as well as plant species composition changes were measured during three field trips that each lasted four days during the growing season of 2021. The results show that soil …