Desirable Host Plant Qualities in Wild Rice \u3ci\u3e(Zizania Palustris)\u3c/i\u3e for Infestation by the Rice Worm \u3ci\u3eApamea Apamiformis\u3c/i\u3e (Lepidoptera: Noctuidae)

The rate at which an insect infests hosts by ovipositioning and/or subsequent growth of larvae often depends on specific desirable host plant qualities. In this study, we measured the infestation rate of wild rice, Zizania palustris, by the wild rice worm, Apamea apamiformis, D. F. Hardwick (Lepidoptera: Noctuidae) and compared it to sediment nitrogen availability, plant biomass, plant density, litter accumulation, and seed carbohydrate and nitrogen concentration. Plant density and litter accumulation had no effect on infestation rates. Infestation rate increased with plant biomass and sediment nitrogen availability. The correlation between infestation rate and sediment nitrogen availability seems to reflect the fact that high nitrogen availability produces larger plants rather than more nutritious seeds as the infestation rate was not correlated with seed glucose content and surprisingly decreased with concentration of nitrogen in seeds. Infestation rate was not related to any other measured quantities. Therefore, Apamea appear to infest larger, rapidly growing host plants which are made possible by high sediment nitrogen availability

Plant and soil microbe responses to light, warming and nitrogen addition in a temperate forest

1. Temperate forests across Europe and eastern North America have become denser since the 1950s due to less intensive forest management and global environmental changes such as nitrogen deposition and climate warming. Denser tree canopies result in lower light availability at the forest floor. This shade may buffer the effects of nitrogen deposition and climate warming on understorey plant communities. 2. We conducted an innovative in situ field experiment to study the responses of co-occurring soil microbial and understorey plant communities to nitrogen addition, enhanced light availability and experimental warming in a full-factorial design. 3. We determined the effects of multiple environmental drivers and their interactions on the soil microbial and understorey plant communities, and assessed to what extent the soil microbial and understorey plant communities covary. 4. High light led to lower biomass of the soil microbes (analysed by phospholipid fatty acids), but the soil microbial structure, i.e. the ratio of fungal biomass to bacterial biomass, was not affected by light availability. The composition of the soil bacterial community (analysed by high-throughput sequencing) was affected by both light availability and warming (and their interaction), but not by nitrogen addition. Yet, the number of unique operational taxonomic units was higher in plots with nitrogen addition, and there were significant interactive effects of light and nitrogen addition. Light availability also determined the composition of the plant community; no effects of nitrogen addition and warming were observed. The soil bacterial and plant communities were co-structured, and light availability explained a large part of the variance of this co-structure. 5. We provide robust evidence for the key role of light in affecting both the soil microbial and plant communities in forest understoreys. Our results advocate for more multifactor global change experiments that investigate the mechanism underlying the (in) direct effects of light on the plant-soil continuum in forests

The role of nitrogen uptake on the competition ability of three vineyard Saccharomyces cerevisiae strains

Three vineyard strains of Saccharomyces cerevisiae, P301.4, P304.4 and P254.12, were assayed in comparison with a commercial industrial strain, QA23. The aim was to understand if nitrogen availability could influence strain competition ability during must fermentation. Pairwise-strain fermentations and co-fermentations with the simultaneous presence of the four strains were performed in synthetic musts at two nitrogen levels: control nitrogen condition (CNC) that assured the suitable assimilable nitrogen amount required by the yeast strains to complete the fermentation and low nitrogen condition (LNC) where nitrogen is present at very low level. Results suggested a strong involvement of nitrogen availability, as the frequency in must of the vineyard strains, respect to QA23, in LNC was always higher than that found in CNC. Moreover, in CNC only strain P304.4 reached the same strain frequency as QA23. P304.4 competition ability increased during the fermentation, indicating better performance when nitrogen availability was dropping down. P301.4 was the only strain sensitive to QA23 killer toxin. In CNC, when it was co-inoculated with the industrial strain QA23, P301.4 was never detected. In LNC, P301.4 after 12 h accounted for 10% of the total population. This percentage increased after 48 h (20%). Single-strain fermentations were also run in both conditions and the nitrogen metabolism further analyzed. Fermentation kinetics, ammonium and amino-acid consumptions and the expression of genes under nitrogen catabolite repression evidenced that vineyard yeasts, and particularly strain P304.4, had higher nitrogen assimilation rate than the commercial control. In conclusion, the high nitrogen assimilation rate seems to be an additional strategy that allowed vineyard yeasts successful competition during the growth in grape musts

2003 Great Bay Organic Nitrogen (PON & DON) and Light Extinction (PAR) Monitoring Program

EPA is developing water qulaity criteria for estuaries that require knowledge of both total nitrogen and light availability (measured as photsynthetically active radiation, PAR). Through the National Estuarine Research Reserve (NERR) System-Wide Monitoring Program (SWMP), inorganic nutrient concentrations, chlorophyll-a concetration, and a number of hydrographic and water quality parameters are sampled on a monthly basis at 7 sites in the Great Bay system. In addition, these same parameters, as well as bacteria concentrations, are measured at a number of sites in Great Bay and Hampton Harbor through the National Coastal Assessment (NCA) funded through the EPA. This project takes advantage of these existing monitoring activities to collect and analyze for particulate organic nitrogen (PON), dissolved organic nitrogen (DON) and photosynthetically active radiation (PAR) at a up to 10 existing sample sites in the New Hampshire seacoast region. When combined with existing dissolved inorganic nitrogen measurements, PON and DON allow the entire Total Nitrogen (TN) pool to be quantified. PAR measurements provide, for the first time, an estimate of the light availability in the system

2006 Great Bay Organic Nitrogen (PON & DON) and Light Extinction (PAR) Monitoring Program

Nitrogen is most often considered to be the limiting nutrient for plant growth in marine waters. As a result, knowledge of nitrogen loading and ambient water-column concentrations are considered to be critical to understanding the response of aquatic ecosystems to nutrient over-enrichment—a process known as eutrophication when it results in the excess production of organic matter. Plant production in many estuarine systems may also be limited by light availability as a result of high levels of turbidity in the water resulting from sediments, dissolved organic matter, and phytoplankton in the water column. Light limitation resulting from human-induced increases in turbidity is known to be particularly deliterious to seagrass production/distribution in some ecosystems and also play an important role in determining how phytoplankton respond to nutrient enrichment. EPA is developing water qulaity criteria for estuaries that require knowledge of both total nitrogen and light availability (measured as photsynthetically active radiation, PAR). Through the National Estuarine Research Reserve (NERR) System-Wide Monitoring Program (SWMP), inorganic nutrient concentrations, chlorophyll-a concetration, and a number of hydrographic and water quality parameters are sampled on a monthly basis at 7 sites in the Great Bay system. This project takes advantage of these existing monitoring activities to collect and analyze for particulate organic nitrogen (PON), dissolved organic nitrogen (DON) and photosynthetically active radiation (PAR) at existing sample sites in the New Hampshire seacoast region. When combined with existing dissolved inorganic nitrogen measurements, PON and DON allow the entire Total Nitrogen (TN) pool to be quantified. PAR measurements provide an estimate of the light availability in the system

Increasing Nitrogen Availability for Rice Growth in Irrigated System in Sourou Valley (Burkina Faso)

Nitrogen is the main nutrient that is limiting yield in irrigated rice (Oryza sativa L.) systems. The availability of N can affect phosphorus and potassium plant uptake and reduce rice yieldsThe effect of fertilizer nitrgogen (N) (prilled urea PU) and briquettes—urea supergranules (USG) on rice nitrogen, phosphorus and potassium uptake,soil total N were investigated in Sourou valley in Burkina Faso in pot experiment the dry season of 2013 on acid soil and alkaline soil. Pot experiment was carried out using a factorial design with the rice variety FKR62N.Field experiment was also carried out in the wet season 2013 in acid soil with two rice varieties (FKR 19 and FKR 62N) using a split plot design.The results indicate that soil total N was higher in the acid soil compared to the alkaline soil during the panicle and flowering stages. Urea Deep Placement (UDP) significantly increased N, P and K uptake. Higher nitrogen content was recorded by urea deep placement with USG throughout the experiment. The amount of total N, P and K increased in rice plant with the UDP during the study.Field experiment also showed that USG application was 13% superior to PU application and gave more yields with the two varieties. The best combination was obtained with rice variety FKR 62N. This study suggests that farmers may derive more yields from the use of USG technology than broadcasting

2004 Great Bay Organic Nitrogen (PON & DON) and Light Extinction (PAR) Monitoring Program

Nitrogen is most often considered to be the limiting nutrient for plant growth in marine waters. As a result, knowledge of nitrogen loading and ambient water-column concentrations are considered to be critical to understanding the response of aquatic ecosystems to nutrient over-enrichment—a process known as eutrophication when it results in the excess production of organic matter. Plant production in many estuarine systems may also be limited by light availability as a result of high levels of turbidity in the water resulting from sediments, dissolved organic matter, and phytoplankton in the water column. Light limitation resulting from human-induced increases in turbidity is known to be particularly deliterious to seagrass production/distribution in some ecosystems and also play an important role in determining how phytoplankton respond to nutrient enrichment. EPA is developing water qulaity criteria for estuaries that require knowledge of both total nitrogen and light availability (measured as photsynthetically active radiation, PAR). Through the National Estuarine Research Reserve (NERR) System-Wide Monitoring Program (SWMP), inorganic nutrient concentrations, chlorophyll-a concetration, and a number of hydrographic and water quality parameters are sampled on a monthly basis at 7 sites in the Great Bay system. In addition, these same parameters, as well as bacteria concentrations, are measured at a number of sites in Great Bay and Hampton Harbor through the National Coastal Assessment (NCA) funded through the EPA. This project takes advantage of these existing monitoring activities to collect and analyze for particulate organic nitrogen (PON), dissolved organic nitrogen (DON) and photosynthetically active radiation (PAR) at a up to 10 existing sample sites in the New Hampshire seacoast region. When combined with existing dissolved inorganic nitrogen measurements, PON and DON allow the entire Total Nitrogen (TN) pool to be quantified. PAR measurements provide, for the first time, an estimate of the light availability in the system

Nitrogen retention/enrichment of 316LN austenitic stainless steel welds

The development of nitrogen enriched austenitic stainless steels has been a source of recent interest due to the abundant availability of nitrogen and by the manner in which nitrogen contributes several beneficial material property effects over a wide service temperature range. It is widely recognised that, in the case of nitrogen enriched 316L, improvements in mechanical property and corrosion resistance are derived from the interstitial influence of nitrogen within the matrix. Consequently, having the best combination of strength, toughness and corrosion resistance relationships found in any group of steels, nitrogen strengthened austenitic stainless steels have tremendous scope for application in areas as diverse as the cryogenic, nuclear, power generation and chemical transportation industries

Nitrogen regulation of protein–protein interactions and transcript levels of GlnK PII regulator and AmtB ammonium transporter homologs in Archaea

Gene homologs of GlnK PII regulators and AmtB-type ammonium transporters are often paired on prokaryotic genomes, suggesting these proteins share an ancient functional relationship. Here, we demonstrate for the first time in Archaea that GlnK associates with AmtB in membrane fractions after ammonium shock, thus, providing a further insight into GlnK-AmtB as an ancient nitrogen sensor pair. For this work, Haloferax mediterranei was advanced for study through the generation of a pyrE2-based counterselection system that was used for targeted gene deletion and expression of Flag-tagged proteins from their native promoters. AmtB1-Flag was detected in membrane fractions of cells grown on nitrate and was found to coimmunoprecipitate with GlnK after ammonium shock. Thus, in analogy to bacteria, the archaeal GlnK PII may block the AmtB1 ammonium transporter under nitrogen-rich conditions. In addition to this regulated protein–protein interaction, the archaeal amtB-glnK gene pairs were found to be highly regulated by nitrogen availability with transcript levels high under conditions of nitrogen limitation and low during nitrogen excess. While transcript levels of glnK-amtB are similarly regulated by nitrogen availability in bacteria, transcriptional regulators of the bacterial glnK promoter including activation by the two-component signal transduction proteins NtrC (GlnG, NRI) and NtrB (GlnL, NRII) and sigma factor σN (σ54) are not conserved in archaea suggesting a novel mechanism of transcriptional control

Plant phenology and seasonal nitrogen availability in Arctic snowbed communities

Thesis (M.S.) University of Alaska Fairbanks, 2006This study was part of the International Tundra Experiment (ITEX) and examined the effects of increased winter snow depth and decreased growing season length on the phenology of four arctic plant species (Betula nana, Salix pulchra, Eriophorum vaginatum, and Vaccinium vitis-idaea) and seasonal nitrogen availability in arctic snowbed communities. Increased snow depth had a large effect on the temporal pattern of first date snow-free in spring, bud break, and flowering, but did not affect the rate of plant development. By contrast, snow depth had a large qualitative effect on N mineralization in deep snow zones, causing a shift in the timing and amount of N mineralized compared to ambient snow zones. Nitrogen mineralization in deep snow zones occurred mainly overwinter, whereas N mineralization in ambient snow zones occurred mainly in spring. Concentrations of soil dissolved organic nitrogen (DON) were approximately 5 times greater than concentrations of inorganic nitrogen (DIN) and did not vary significantly over the season. Projected increases in the depth and duration of snow cover in arctic plant communities will likely have minor effects on plant phenology, but potentially large effects on patterns of N cycling