C02 Concentration Research Articles

The Influence of Greenhouse Effect on Earth’s Atmosphere Based on Artificial Intelligence

Greenhouse gases absorb and release a large amount of ground thermal radiation, and modify part of the energy between the earth and the atmosphere, so that it has a greenhouse effect. It is the main cause of global warming and climate anomaly caused by modern human activities. In order to solve the shortcomings of the existing research on the impact of greenhouse effect on the Earth’s atmosphere, this paper briefly introduces the numerical methods of radiation and heat conduction coupling, the components of the Earth’s atmosphere, and the sources and sinks of greenhouse gases. The calculation and analysis of spectral absorption coefficient and the configuration of super parameters of depth learning model are discussed. A numerical simulation of carbon dioxide concentration based on depth learning is constructed and the C02 concentration profile is calculated using the C02 statistical inversion flow of principal component analysis. The calculated temperatures of the standard atmosphere and the standard atmosphere with the carbon dioxide concentration doubled were compared. The data showed that the temperature in the upper stratosphere rose to 58.

The Role of Carbon Dioxide in the Rat Acute Stroke Penumbra.

PurposeThe vasodilatory response to inhaled CO2 occurs in the acute stroke ischemic penumbra and may be a potential therapeutic modality.MethodsTwenty-two Sprague-Dawley rats were subjected to 90-min occlusion of the M2 segment of the middle cerebral artery (M2CAO) by endovascular technique. The animals were administered different C02 concentrations and scanned serially with 9.4 T MRI. Infarct tissue was determined by diffusion-weighted imaging (DWI) and hypoperfused tissue was determined by arterial spin labeling (PWI).Results4 animals were administered room air (RA)+ 6% CO2 (group 1), 6 animals RA+12% CO2 (Group 2) and 4 animals only RA (group 3). In the rats with CO2 administered (groups 1 and 2), the DWI lesion to cerebral hypoperfusion volume ratio (SD) at pre-CO2 administration, was 0.145(0.168), which increased to 0.708(0.731) during CO2 administration and reduced to 0.533(0.527) post-CO2 administration. In 9 of 10 rats the hypoperfused volume decreased when CO2 was administered. When CO2 was stopped the hypoperfused volume became larger again. Administration of RA+12% CO2 (Group 2) decreased the volume of CBF hypoperfusion significantly compared to the control group (95%CI: 0.084 ± 0.0213, p = 0.004).ConclusionInhaled CO2 appears to reduce the size of the hypoperfused tissue volume during acute stroke and may be a potential modality for treatment of acute ischemic stroke. These findings will nonetheless need to be validated in a larger cohort in other centers.

A Novel Disease Divination System Using Field Data

Agriculture, a scientific discipline and skillful activity of cultivating flora and domestic animals. One of the major employment sectors of India is agriculture. Agriculture is the one of the major pillar for Indian economy and backs the whole financial chain of the country. To improve quality of farming, a smart objects network based system can be suggested. A smart objects network arrangement consists of several devices – such as an actuator, a sensor – that are connected to the public network either straightforwardly or not directly. In this paper, a novel system is developed using various sensing devices to collect the data related to soil moisture, temperature, humidity and carbon dioxide concentration – for detecting occurrences of fungal diseases on a chilly plant. The sensors are deployed in the farm and data are transmitted to Arduino Uno (Microcontroller) through wired network. The parametric values fetched from these sensors are sent to the cloud. In ThingSpeak – a cloud platform – where the cleaned data is used – with trained data values – like temperature, humidity, C02 concentration and soil moisture – for the purpose of prediction. If disparity occurred with reference to known threshold value, then warning is sent to the planter either as a SMS on to the mobile or through a push e-mail on to the inbox of the planter with disease control counter measures.

Gas-liquid mass transfer of carbon dioxide capture by magnesium hydroxide slurry in a bubble column reactor

Magnesium hydroxide (Mg(OH)2) has been considered as a potential solvent for C02 removal of coal-fired power plant and biomass gas. The chemistry action and mass to transfer mechanism of C02-H20-Mg(OH)2 system in a slurry bubble column reactor was described, and a reliable computational model was developed. The overall mass transfer coefficient and surface area per unit volume were obtained using experimental approach and simulation with software assistance. The results show that the mass transfer process of C02 absorbed by Mg(OH)2 slurry is mainly liquid-controlled, and slurry concentration and temperature are main contributory factors of volumetric mass transfer coefficient and liquid side mass transfer coefficient. High concentration of C02 has an adverse effect on its absorption because it leads to the fast deposition of MgC03-3H20 crystals on the surfaces of unreacted Mg(OH)2 particles, reducing the utilization ratio of magnesium hydroxide. Meanwhile, high CO32 ion concentration limits the dissolution of MgC03 to absorb C02 continually. Concentration of 0.05 mol/L Mg(OH)2, 15% vol C02 gas and operation temperature at 35 °C are recommended for this C02 capture system

Recurrent Neural Network Model for Prediction of Microclimate in Solar Greenhouse

A recurrent neural network(RNN) based dynamic back propagation(BP) algorithm model with historical internal inputs are developed to predict the temperature and humidity of a solar greenhouse in the north of China. Climate data including air and substrate temperature, air humidity, illumination and C02 concentration recorded over eight days were used to build and validate models for climatic prediction. In order to compare the accuracy of predictions, different performance measures, such as average relative error (ARE), mean absolute error (AME) and root mean square error (RSME), were calculated, for using BP and untrained RNN neural networks using the same processing. For the RNN model, a context layer as the last hidden layer output, is input with the next input to the next hidden layer, which is equivalent to the state feedback. The results demonstrate that the RNN-BP model provides reasonably good predictions with the RSME for temperature 0.751 and 0.781 for humidity, including both of the R2 is both above 0.9, which outperforms the compared models tested in this paper.

The Ecologies of Food Power: An Introduction to the Environment and Food Book Symposium

of May, 2013, the concentration of C02 in the atmosphere tipped over 400 parts per million (ppm) suggesting that the pathway to a climate changed world is not only accelerating but doing so in ways that are surprising the majority of climate scientists (Bawden, 2013). The supreme irony of this is that, as part of the continuing effort to deliver ever greater quantities of greenhouse gas-rich cheap protein sources, the political ground is being sown in the UK for the growth of US-styled ‘mega’ livestock and fish farms (Milmo and Levitt, 2013). Meanwhile parallel news reports spoke of how UK supermarkets will begin to source chicken fed with GM feeds at the behest of ‘food cartels and GM food giants’ (Dorward, 2013) and, in the US, a unanimous Supreme Court decision strengthenedcorporate control over seed patents to the benefit of the likes of Monsanto (Goldenberg, 2013). At the same time all this was going on, other more ostensibly quotidian stories were being told about how, in Britain, there has not only been a rise in austerity-fuelled hunger (Carr, 2013), but that scientific evidence reveals growing links amongst middle-age obesity, ill-health and dementia (McKie, 2013). To top it all off, the UN is now recommending ‘insect farming’ as a way to not only reduce the environmental impacts of farming, but also feed growing global populations (Vidal, 2013). What all of these seemingly unrelated reports suggest is that not only is there still quite a bit going on in the ‘worlds of food’ (Morgan, et al 2006)—indeed, the above events and reports happened within two

Carbon Dioxide Anesthesia ofTamarixia radiata(Hymenoptera: Eulophidae) Parasitoid ofDiaphorina citri(Hemiptera: Psyllidae)

Tamarixia radiata (Waterston) (Hymenoptera: A T. radiata colony was maintained at Eulophidae), is an arrhenotokous ectoparasite of FDACS-DPI in Gainesville on ACP nymphs the Asian citrus psyllid (ACP) Diaphorina citri using orange jasmine, Murraya paniculata (Kuwayama) (Hemiptera; Psyllidae), vector of (1.) Jack (Sapindales: Rutaceae), as plant host citrus greening disease or huanglongbing (HLB). (Skelley & Hoy 2004). Six newly trimmed The parasitoid is reported to have controlled plants with new growth were held in an acrylic ACP populations to low levels on the islands of 62 cm cubic cage and 600 D. citri adults were Reunion, Guadeloupe and Puerto Rico (Aubert released for 72 h for oviposition a greenhouse & Quilici 1984; Etienne et al. 2001; Pluke et al. under natural sunlight 25 ± 5 °C and 50% ~ 2008). Tamarixia radiata was first imported to 70% RH. Adults were removed and plants held Florida from Taiwan and Vietnam in 1998 and for 10 d until 4th instar nymphs were available, released in 1999-2001 (Hoy & Nguyen 2001). A Plants were moved into another clean cage of survey conducted in 2006-07 determined that T. the same type for 20 days into which 100 T. ra radiata was well distributed in citrus orchards diata were released. Adult progeny were later throughout the state (Qureshi et al. 2009). Howcollected daily until no more emerged, ever, incidence of parasitism was generally low, A gas chamber was constructed consisting of a especially early in the growing season, suggesting vial, 6.50 cm in diam and 12 cm in height (Fish a need for augmenting parasitoid populations at er Scientific, Pittsburg Pennsylvania), provided that critical time as component of an integrated with two 0.50 cm diam holes in the lid into each management program (Qureshi et al. 2007,2009). of which was fitted a 0.5 cm plastic tube inserted Studies of T. radiata biology and current efforts either 1 cm or 11 cm into the chamber for a gas at mass rearing and release of this species might outlet and inlet respectively. Plasticine modeling benefit from an ability inactivate adults by C02 clay (Flair Leisure Products, Cheam Surrey, Eng anesthetization, including separation of emerland) was molded around the openings of the lid gent wasps and psyllids. to prevent leakage. Carbon dioxide (C02) is widely used to anesFlow time of gas at 3.8 kpa (2 psi) needed to thetize insects, but may also cause deleteridisplace all air in the chamber was assessed by ous side effects on biology and behavior. Brooks filling the vial with water and then replacing (1957) found that development rate of German with C02 through the inlet. All the water was dis cockroach, Blattella germanica L. (Blattodea: placed in 10 s. A C02 sensor (K-33 ICB 30% CO, Blattellidae), nymphs decreased 53% when exSensor, C02Meter Inc., Ormond Beach Florida, posed weekly to high C02 concentrations for 3 USA) was used to determine that 3 s of flow time min. Crystal (1967) reported significantly dewere necessary to attain a 30% C02 concentration creased survival rates and fertility of screwworm, confirming the earlier result. The C02 sensor was Cochliomyia homini-vorax (Coquerel) (Diptera: also used to test for leaks by confirming that a Calliphoridae), exposed to 100% C02 for 30 min. given concentration remained constant over sev Sherman (1953) reported that C02 anesthesia of eral min. Mediterranean fruit fly, Ceratitis capitata (WiFive wasps having emerged within 24 h or less edemann) (Diptera: Tephritidae), led to increased were placed in the chamber. The lower % of the mortality. vial was covered with black cloth to induce the This study was undertaken as a first step towasps to walk to the top and thus avoid injury ward using anesthetization for mass rearing by from in rushing gas. Gas was introduced through evaluating the response of T. radiata to C02 exan inlet from a C02 tank at 3.8 kpa for 15s to posure. The objective was to test the effectiveness exchange all the air, and then the 2 tubes closed of C02 anesthetization of T. radiata and to deterwith metal clamps. Wasps were removed after a mine the incidence and severity of side effects of 5 min exposure and observed with the naked eye C02 anesthetization on longevity, parasitism rate using a stop watch to record recovery time (nor and sex ratio. mal movement). Males and females were treated

Climate Hedging Explained

The causal relationship between atmospheric CO2 concentrations and global temperature is well established, but the degree of sensitivity of future temperature rise to both existing levels of CO2 and continued carbon emissions is still subject to a high degree of uncertainty. Governments have responded to the future threat of further global warming on economic growth by proposing a variety of carbon emission mitigation approaches such as cap-and-trade or carbon tax mechanisms. Yet, such approaches have two central weaknesses: 1) they are targeted at the wrong variable, C02 concentration rather than temperature, and 2) by their very design they create incentives for high carbon emitters to circumvent the regulatory systems established and become free riders on those pursing aggressive mitigation policies. Building on the sea level climate derivative concept proposed by Bloch, Annan and Bowles, the authors propose a new range of Climate Derivatives such as Climate Coupon Bond and Climate EOption whose pay-offs are dependent on global temperature rise. The Climate Derivatives would create both a vehicle and an incentive for high carbon emitting companies, industries and countries to help finance new technologies and industries that will reduce carbon emissions in the future. Moreover, the instruments would dynamically reflect and incorporate any new information that helps predict the path of temperature rise through time and, in effect, would put a price on the probabilities associated with a variety of climate change scenarios.

ChemInform Abstract: The Effects of Carbon Dioxide, Methanol, and Alkali Promoter Concentration on the Higher Alcohol Synthesis Over a Cu/ZnO/Cr2O3 Catalyst.

The behavior of the methanol and higher alcohol (HAS) syntheses as a function of catalyst promoter concentration, C02 feed gas concentration, and methanol feed gas concentration has been investigated over a Cu/ZnO/Cr203 catalyst at 10 MPa and 285–315°C. In the presence of C02 in the feed gas, the methanol and HAS yields are greater for the unpromoted catalyst than the 0.5% K2CO3-promoted catalyst. The methanol and HAS yields also reach a maximum as the C02 concentration increases for both catalysts. In the absence of C02, both the methanol and HAS yields reach a maximum as the K2CO3 promoter concentration increases. The complex behavior results from the ability of these catalysts to incorporate CO, C02, and methanol into higher alcohols, on at least two different types of catalytic sites. It is suggested that C02 participates directly in HAS on copper sites while alkali/copper interfacial sites are involved in converting CO. Higher alcohol production is therefore very sensitive to the feed gas composition and the components and composition of the catalyst.

Mass Spectra Deconvolution of Low, Medium, and High Volatility Biogenic Secondary Organic Aerosol

Secondary organic aerosol (SOA) consists of compounds with a wide range of volatilities and its ambient concentration is sensitive to this volatility distribution. Recent field studies have shown that the typical mass spectrum of ambient oxygenated organic aerosol (OOA) as measured by the Aerodyne Aerosol Mass Spectrometer (AMS) is quite different from the SOA mass spectra reported in smog chamber experiments. Part of this discrepancy is due to the dependence of SOA composition on the organic aerosol concentration. High precursor concentrations lead to higher concentrations of the more volatile species in the produced SOA while at lower concentrations the less volatile compounds dominate the SOA composition. alpha-Pinene, beta-pinene, d-limonene, and beta-caryophyllene ozonolysis experiments were performed at moderate concentration levels. Using a thermodenuder the more volatile SOA species were removed achieving even lower SOA concentration. The less volatile fraction was then chemically characterized by an AMS. The signal fraction of m/z44, and thus the concentration of C02+, is significantly higher for the less volatile SOA. High NO(x) conditions result in less oxidized SOA than low NO(x) conditions, while increasing relative humidity levels results in more oxidized products for limonene but has little effect on alpha-and beta-pinene SOA. Combining a smog chamber with a thermodenuder model employing the volatility basis-set framework, the AMS SOA mass spectrum for each experiment and for each precursor is deconvoluted into low, medium, and high volatility component mass spectra. The spectrum of the surrogate component with the lower volatility is quite similar to that of ambient OOA.

Effects of high C02 concentration on deep-sea benthic communities using a benthic chamber system.

Effects of high C02 concentration on deep-sea benthic communities using a benthic chamber system.

Assessment of impact of climate change on productivity of tea (Camellia sinensis L.) plantations in Sri Lanka

The Journal of the National Science Foundation of Sri Lanka publishes the results of research in all aspects of Science and Technology. The journal also has a website at http://www.nsf.gov.lk/. 2020 Impact Factor: 0.515The JNSF provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge.

Combined Effects of Elevated Temperature and Carbon Dioxide on Geometry of Maize Leaves

An accurate prediction of variations in water consumption from a field and in the crop growih affected by the climate change due to global warming is important for the continuous agricultural activities. Components of water consumption in a farrnland, i.e. transpiration from the crop surface and evaporation from the soil surface, are influenced by the structure of crop canopy. In this study, the combined effects of elevated temperature and carbon dioxide (C02) concentration on the geometry and longevity of leaves of maize were examined through an experiment with growih chambers. Three treatments, i.e. TLCL (air temperature day/night: 28/22'C, C02 concentration: 350ppm), TLCH (28/22'C, 750ppm), and THCH (32/26'C, 750 ppm), were performed in different closed chamber respectively, and sixteen of maize (Zea mays L. cv. Pioneer G-98) planted in a pot were grown in each treatment. The cumulative thermal time from emergence of plant until the expansion of the ith leaf became larger in the order, TLCH<TLCL< THCH. The longevity of the ith leaf became longer in the order, TLCL<TLCH<THCH. Area of the ith leaf

Effects of Elevated CO2 Concentration on Photosynthetic Carbon Metabolism in Flag-Leaf Blades of Rice before and after Heading

We monitored the effects of elevated atmospheric C02 concentrations on the photosynthetic carbon metabolism in the flag leaves of rice plant (Oryza sativaL. cv. Akitakomachi) before and after heading. The plants were grown under ambient (350 ppm : control) or elevated (650 ppm) C02 conditions. Flag-leaf blades grown under high C02 accumulated more starch than control leaf blades before heading, but the level of starch declined to almost zero under both C02 concentrations as soon as the development of ears began. Before heading, the transcript level of sucrose-phosphate synthase (SPS) (EC 2.4.1.14), a key enzyme in the sucrose synthesis in flag-leaf blades was significantly higher under elevated C02 conditions than under elevated C02 (P<0.01). The difference in the expression of SPS decreased after heading, coinciding with a change in starch contents in both groups. These results showed that the effects of elevated C02 concentration on rice plants might vary with the growth stage of the leaf blades. We also discussed the influence of the changes in the carbohydrate metabolism of rice plants caused by elevated C02 concentration on yield.

Response of Transpiration Characteristics and Water Use Efficiency of Setaria viridis to the Enhancement of Simulated Photosynthetic Radiation and CO2 Enrichment

To determine how transpiration characteristics and water use efficiency of annual €4 plants respond to simulated photosynthetic radiation enhancement and CO2 enrichment, we used LT-6400 Portable Photosynthesis System to examine photosynthesis rate ( Pn ) , transpiration rate ( Tr ) , intercellular CO2 concentration ( Ci) , stomatal conductance ( Gs ) and vapor deficit at the leaf surface ( Vpdl) of Setaria viridis under simulated photosynthetic radiation (SPR) intensities from 0 to 2 400 jumol · m -2 · s-1 and CO2 concentration from 300 to 1 000 μmol · mol -1. Pn, Tr and Gs increased with enhanced SPR intensity. The increase in Pn, Tr and Gs with each unit SPR added was reduced as SPR intensity increased. At last, these physiological parameters tend to dynamic balance. Water use efficiency ( WUE) increased with enhanced SPR, then plateaued as SPR intensity exceeded 1 200 μmol·m-2 ·s-1 . For photosynthesis process demands C02, so Ci intensity enhancement. Vpdl also decreased with SPR intensity increase, then reached dynamic balance as SPR intensity exceeded 600 μmol · m- 2 · s-1. Pn increased with CO2 concentration between 300 and 600μmol · mol -1, and then decreased as C02 concentration increased from 600 to 1 000 μmol· mol-1. Ci, Vpdl and WUE of Setaria viridis rose with the elevation of CO2 concentration. Both Gs and Tr dropped as the CO2 concentration was elevated . We conclude that Pn of annual C4 plants was not sensitive to C02 concentration variation. The response of Tr and WUE to CO2 enrichment was most significant. It is obvious that the function of instantaneous simulated CO2 enrichment to increased photosynthesis rate was gradually diminished. However, it could enhance primary production by improving the use efficiency of existing water.

Refining our understanding of oceanic biogeochemistry and ecosystem functioning

On societally relevant time scales (e.g., decades to centuries), oceanic biological processes sequester large quantities of atmospheric carbon, thereby modulating C02 concentrations in the lower atmosphere [IPCC, 2001]. The complex physical and biogeochemical interactions that regulate carbon fluxes between the atmosphere and the surface ocean— apparently random physical events, fluctuations in community structure and function, natural climate cycles, and long‐term changes in anthropogenic forcing—are best studied within the framework of ocean time‐series observations. Such thinking led in 1988 to the initiation of the U.S. JGOFS (Joint Global Ocean Flux Study) time‐series programs in the subtropical North Atlantic (BATS = Bermuda Atlantic Time‐series Study) and North Pacific (HOT = Hawaii Ocean Time‐series), and motivates continuing observations into the foreseeable future. After 14 years of intensive physical, biological, and biogeochemical sampling in these regions, the paradigms that initially guided our understanding and research of ocean ecosystems have been found wanting, and new perspectives have emerged to provide a stimulating foundation for continued investigations.

International Symposium on Transplant Production in Closed Systems for Solving the Global Issues on Environmental Conservation, Food Resources, and Energy

This symposium, with the longest name of those I have ever attended, was certainly not stretched out in time. It was a compact, very well organized meeting with 50 presentations in 3 days covering a wide range of plant transplant technology. Having participated in a symposium in Yokohama 8 years ago, at which I was impressed with the presentations on somatic embryogenesis, I was anxious to go to this meeting. Not many of the 150 participants came from Europe; however 13 countries were present, most from the eastern latitudes, with a number of American and Canadian scientists also present. The symposium started with an opening address by the legendary Dr. Atsushi Komamine. He explained that this symposium is a part of the outcome of the Japanese Research for the Future Program, started in 1996 with a budget of 2.4 billion yen for 4 years, dealing with the expected crisis in the biosphere on earth sometime in the 21st century. He stressed that the application of different biotechnologies should prevent this crisis. Genetic engineering for tolerance to environmental stress, molecular approaches for improvement of productivity, and production of resistant plants may form part of the solution. Another part is thought to be mass propagation of (woody) plants in an economically reliable way. Concepts and technologyfor closed plant production systems. The USA experts Drs. Giacomelli and Ting, and a major contributor to the symposium, Dr. Kozai from Japan, covered the first introductory session on concepts and technology. The application of machines equipped with vision technology for intensive seedling production becomes routine in a fast way. However, the environment still greatly affects seedling growth habit, final seedling quality, and ultimately the quality of the mature plant. Developments were presented of precise and uniform plant environments within closed low-mass systems with a recirculating atmosphere. The importance of this was demonstrated by the selection of morphologically similar seedlings (by radicle length and leaf size) leading to improved mature plant quality. Of the batches selected, measuring net photosynthesis and leaf temperature may lead to real-time plantbased (micro)-environmental control. 'Phytomation' is the word for this technology, leading to plant factories and biomass production units for space journeys as carried out by NASA. Theoretical studies to effectively describe the components of closed plant production systems have led to a set of 'foundation classes', resulting in a first version of a Java-based computer model describing a crop production system for long-duration human exploration of space. No-w ste systems? The necessity of closed systems for (tissue culture) transplants will, according to Dr. Kozai, become more serious in the coming decades because limitations will be set to the polluting open systems. Resources such as heating, cooling, vessels, trays, gar, water and labor will become more expensive, and thus wa e has to be minimized. A photoautotrophic closed tissue culture productio system reduces this waste and increases the final quality of the plants, compared to some traditional systems, by at least 30%. A closed transplant production system is defined as a tran plant production system covered with opaque walls, with minimized or controlled ventilation rates, using artificial lighting. So with this system, photoperiod, light intensity and quality, air temperature, humidity, C02 concentration and air current speed can be completely controlled. Photoautotrophic micropropagation and scaling-up. A historical overview of the evolution of vessels used in tissue culture shows a

Impact of changing atmospheric CO2 concentrations over the Phanerozoic on stomatal parameters of vascular land plants

A novel and multi-disciplinary subject involving the relationships between changes in atmospheric C02 concentration throughout the geological history and features of plant anatomy is reviewed. Particular attention will be given to stomatal parameters (stomatal density and stomatal index) which are recorded at a cellular level in fossil plants and the relationships of these observable parameters to earth life history and global environmental change. Trends of atmospheric CO2, concentrations during the Phanerozoic period are briefly introduced and recent conceptual advances in understanding the causal mechanisms for changes in stomatal parameters of land vascular plants are considered. In addition, some of the inherent problems and limitations of this kind of work are discussed and future research directions are presented.

Susclime: A Simulation/Game on Population and Development in a Climate-Constrained World

The simulation/game SUSCLIME is introduced as a tool to explore long-termfutures. The model world of SUSCLIME is briefly described. It is a simple world with a goods-producing and a service-providing capital stock, the latter including consumption. There are two countries. The players of each country allocate the industrial output between these two stocks and three energy capital stocks: oil, renewable, or efficiency. The two countries can trade oil and make loans. The major goal is to go through the demographic transition by increasing the welfare per person and making the transition from oil to renewable energy. The latter is needed to avoid negative impacts on the economy due to rising C02 concentrations. Some illustrative outcomes and game experiences are discussed.

Postharvest sprouting of onion bulbs grown in different temperature and C02 environments in the UK

SummaryThe effects of different mean growing season temperatures and C02 concentrations during bulb production on postharvest bulb sprouting in a common storage environment at Reading, UK, was examined in two cultivars of the Rijnsburger type of onion (Allium cepa L.). Crops were grown in the field in temperature gradient tunnels maintained at either 374 or 532 ppm C02. At crop maturity, cohorts of bulbs were harvested, transferred to a constant temperature room (at an average of 11.6°C) and the subsequent duration to sprouting recorded. The duration to the onset of sprouting (expressed as days in storage until the first bulb sprouted) was not affected by cultivar, mean growing season temperature or CO2 concentration, and was 165 d. The subsequent rate of sprouting (expressed as bulbs per day) was a positive linear function of mean growing season temperature, but no effects of CO2 or cultivar were detected. Mean rate of sprouting increased from an average of 0.036 bulbs per day at 12.3°C to 0.093 bulbs per day at 18.6°C. Rapid sprouting in storage was associated with lower levels of total non-structural carbohydrate in the bulbs at the time of harvest. Thus, postharvest susceptibility of onion bulbs to sprouting in storage is expected to increase in warmer crop production temperatures.