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.
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Showing 1 to 20 of 35 for “"photosynthetically active radiation (PAR)"”.
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Corticular Photosynthetic Dynamics for a Coastal Evergreen Shrub: Myrica Cerifera
… during summer. Variations in % refixation paralleled changes in photosynthetically active radiation (PAR). As light attenuated with increasing branch order % refixation decreased. Increased PAR in the winter due to a more sparse canopy lead to increases in % refixation. Total chlorophyll …
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Variability within the 10-year pollen rain of a seasonal neotropical forest
… effect of the current year’s temperature and photosynthetically active radiation (PAR). Our results demonstrate the relative stability of the long-term pollen rain as a larger regional signal of flowering response to climatic variability, while also suggesting that paleoecological …
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Quantifying pelagic primary production and respiration via an automated in-situ incubation system
… production via pelagic primary production are of particular importance in surface ocean and in shallow aquatic ecosystems where photosynthetically active radiation (PAR) is abundant. However, the dynamic nature and large degree of heterogeneity in these ecosystems pose substantial challenges for …
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Establishment of native plant species for livestock forage in silvopasture systems
… how differences in environmental factors (Photosynthetically Active Radiation (PAR), ambient temperature, and soil moisture) associated with each treatment affect establishment of native plant species. The experiment was a Randomized Complete Block Design replicated in 2020 and 2021. …
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Context-dependent controls of periphyton across the littoral-benthic habitat of deep, clear lakes
… (NDS), water column nutrient data, and photosynthetically active radiation (PAR) measurements. We observed that periphyton nutrient limitation and inhibition vary with depth and habitat. Differences were primarily driven by the concentration of dissolved inorganic nitrogen (DIN) and the …
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The potential application of variable renewable energy supplies to increase the horticultural productivity of the Isle of Lewis, Scotland.
… on Lewis was characterised. The mean ratio of photosynthetically active radiation (PAR) to solar radiation (SR) (fE) recorded in 2010 was 0.458. fE was found to be significantly different between the first and last hour of daylight and 12:00 GMT (F, (2, 33) = 7.98, p<0.001) and between winter …
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Seasonal and Spatial Variation in Leaf Area Index, Litter Production, and Light Levels in Myrica Cerifera,Shrub Thickets Across a Barrier Island Chronsequence
… a successional chronosequence and compare methods of estimating LA1 in shrub- dominated systems. Seasonal LA1 estimates were made seven times throughout the year with a portable integrating radiometer (Li-Cor LAI-2000) and three times by measurement of photosynthetically active …
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The effect of non-glaucousness, as conferred by Inhibitor of Wax 1, on physiology and yield of UK Wheat
… Iw1. This PhD tests the hypothesis that Iw1 imparts an advantage for wheat yield and physiology in the UK. Crossing Shamrock with six glaucous UK winter wheat varieties (Malacca, Alchemy, Hereward, Xi19, Robigus and Einstein) created non-glaucous near isogenic lines (NILs) with Iw1. NILs were …
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Ecological Effects of Overwater Structures on Subtidal Kelp, Northern Puget Sound, Washington
… of 2017 for subtidal kelp distribution, biomass, photosynthetically active radiation (PAR), substrate, and fish presence. Georeferenced benthic video surveys were conducted along parallel transects to create 1 m grid cell maps encoded for subtidal kelp presence/absence at each site. Wet biomass …
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Revealing drivers of nitrous oxide (N2O) fluxes in a thawing sub-Arctic permafrost peatland
… fluxes under both light conditions using transparent chambers and dark conditions using opaque chambers. The results show that the nutrient-poor peatland functions as a continuous, non-negligible but small sink for N₂O during the snow-free season, providing the first in situ evidence of …
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Ground vegetation gross primary production dynamics of a drained peatland forest ecosystem
… terrestrial carbon (C). These peatlands were partly drained for agriculture and forestry. In drained peatland forest, beside tree stands, ground vegetation is another relevant component concerning C fluxes between the land and the atmosphere. Thus, to explore ground vegetation gross primary …
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Non-growing season CO2 fluxes of a boreal fen – key drivers and responses to anomalous winter conditions
… vapor pressure deficit, water table depth, and photosynthetically active radiation (PAR) on NEE of CO2 was analyzed with a random forest algorithm. PAR and soil temperature were the most important drivers during non growing season, growing season and year-round periods. PAR had the highest …
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Photoprotective role of beta -carotene and antioxidant enzymes: A shield against ultraviolet damage in Dunaliella bardawil
… during exposure to stress or high irradiances of photosynthetically active radiation (PAR: 400-700 nm) while Dunaliella salina (UTEX 200) lacks this ability. Cells were cultured in two irradiances (150 and 35 mumol photons ·m-2·s -1), and then exposed to high red (wavelengths > 590 …
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Productivity, Carbon Sequestration, Nutrient Accumulation, And Species Interactions In Perennial Biomass Alley Cropping Systems
… (Panicum virgatum L.), prairie cordgrass (Spartina pectinata Bosc ex Link), ‘Rush’ intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth and Dewey cv. Rush), and an eleven species native polyculture. After four years of growth, we found that NM6 poplar alley cropping systems …
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Impacts of Laurel Wilt Disease on Redbay (Persea Borbonia) Population Structure and Forest Communities in the Coastal Plain of Georgia, USA
… redbay and their associated communities were compared in five sites infested with LWD and three un-infested sites in five counties in Georgia. Tree, shrub, and herb layers were sampled separately to determine redbay population structure and community composition and structure. Only 8% of redbay …
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Automated PAM Fluorometry as a Tool to Evaluate the Photosynthetic Response of Undaria pinnatifida to Experimental Warming
… the relative electron transport rate (rETR) and photosynthetically active radiation(PAR) curves, with the slope (alpha) serving as a proxy for the efficiency of U. pinnatifida’s photosystem II (PSII). Inspection of the multi-day time series of alpha revealed a significant decline in PSII …
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Phenology Effects on Carbon and Water Dynamics in a Pristine Boreal Fen A multi-decadal analysis from 2005-2007 & 2014-2022
… temperature (T), vapor pressure deficit (VPD), photosynthetically active radiation (PAR) and rain were included and tested with various statistical methods (trend- and correlation-analysis, commonality analysis, time lag testing, stepwise multiple-regression, and structural equation modelling). …
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Photosynthetic and oxidative stress in the green alga Dunaliella tertiolecta: The effects of UV-B and UV-A radiation
… have been made to elucidate the effects of UV-B radiation on primary producers such as phytoplankton and plants. Considerably less effort has been devoted to describing the role played by ultraviolet-A (UV-A; 320-400 nm) radiation, which is not attenuated by stratospheric ozone. The present work …
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Effect of plant density on soybean seed yield and quality
… which in turn was a function of the amount of photosynthetically active radiation (PAR) intercepted by the canopy. A green area index (GAI) of 3.4-3.6 was required to attain canopy closure interception of >95% incoming photosynthetically active radiation). Seed yield was also strongly related …
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Chromatophore tissue density and skeletal density banding as a measure of the adaptive response of healthy corals to environmental change
… the coral animal from harmful ultraviolet (UV) radiation. Yet connections have not previously been drawn between changes in the tissue density of chromatophores and the development of skeletal density bands in “apparently healthy” corals (corals with no outward visible indication of distress or …
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