In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L...In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L:D=12:12,14:10 and 10:14),temperature(15℃(LT),25℃(MT)and 30℃(HT))and light intensity(100,200 and 400μmol m^(−2)s^(−1),noted as LL,ML and HL,respectively)conditions.Then the maturation time,spore release number and chlorophyll fluorescence were analyzed.The results suggested that:1)The spore maturation time was accelerated by higher temperature or higher light intensity from 62 h to 36 h,and changes in day length accelerated the spore maturation to a certain extent as compared with 12:12 light/dark cycle;2)Higher light intensity significantly decreased the chlorophyll fluorescence(Fv′/Fm′,NPQ,rETRmax andα)of the mature reproductive segment under 30℃with 12:12 light/dark cycle.But when in the other photoperiods(10:14 and 14:10 conditions),the inhibitory effects of high light intensity were alleviated significantly;3)The optimum condition for the spore maturation and release was 12:12 light/dark cycle,25℃,400μmol m^(−2)s^(−1),with both shorter and longer photoperiod reducing the spore release number;4)Higher light intensity significantly increased the spore release number under 25℃,but these effects were alleviated by 30℃treatment.This study is the first attempt to elucidate the coincidence effects of photoperiod,temperature and light intensity on the reproduction of Ulva,which would help to reveal the mechanism of the rapid proliferation of green tide.展开更多
The miscibility of flue gas and different types of light oils is investigated through slender-tube miscible displacement experiment at high temperature and high pressure.Under the conditions of high temperature and hi...The miscibility of flue gas and different types of light oils is investigated through slender-tube miscible displacement experiment at high temperature and high pressure.Under the conditions of high temperature and high pressure,the miscible displacement of flue gas and light oil is possible.At the same temperature,there is a linear relationship between oil displacement efficiency and pressure.At the same pressure,the oil displacement efficiency increases gently and then rapidly to more than 90% to achieve miscible displacement with the increase of temperature.The rapid increase of oil displacement efficiency is closely related to the process that the light components of oil transit in phase state due to distillation with the rise of temperature.Moreover,at the same pressure,the lighter the oil,the lower the minimum miscibility temperature between flue gas and oil,which allows easier miscibility and ultimately better performance of thermal miscible flooding by air injection.The miscibility between flue gas and light oil at high temperature and high pressure is more typically characterized by phase transition at high temperature in supercritical state,and it is different from the contact extraction miscibility of CO_(2) under conventional high pressure conditions.展开更多
Chlorophyll,a green pigment in photosynthetic organisms,is generated by two distinct biochemical pathways,the tetrapyrrole biosynthetic pathway(TBP) and the methylerythritol 4-phosphate(MEP)pathway.MEP is one of the p...Chlorophyll,a green pigment in photosynthetic organisms,is generated by two distinct biochemical pathways,the tetrapyrrole biosynthetic pathway(TBP) and the methylerythritol 4-phosphate(MEP)pathway.MEP is one of the pathways for isoprenoid synthesis in plants,with 4-hydroxy-3-methylbut-2-enyl diphosphate reductase(HDR) catalyzing its last step.In this study,we isolated a greenrevertible yellow leaf mutant gry3 in rice and cloned the GRY3 gene,which encodes a HDR participating in geranylgeranyl diphosphate(GGPP) biosynthesis in chloroplast.A complementation experiment confirmed that a missense mutation(C to T) in the fourth exon of LOC_Os03g52170 causes the gry3 phenotype.Under high temperature and high light,transcript and protein abundances of GRY3 were reduced in the gry3 mutant.Transcriptional expression of chlorophyll biosynthesis,chloroplast development,and genes involved in photosynthesis were also affected.Excessive reactive oxygen species accumulation,cell death,and photosynthetic proteins degradation were occurred in the mutant.The content of GGPP was reduced in gry3 compared with Nipponbare,resulting in a stoichiometric imbalance of tetrapyrrolic chlorophyll precursors.These results shed light on the response of chloroplast biogenesis and maintenance in plants to high-temperature and high-light stress.展开更多
Ulmus crassifolia Nutt. (Cedar elm, Ulmaceae) is a tree found in central and east Texas, northern Mexico, east to Florida, and north to southern Missouri and Oklahoma. Ungnadia speciosa Endl. (Mexican-buckeye, Sapinda...Ulmus crassifolia Nutt. (Cedar elm, Ulmaceae) is a tree found in central and east Texas, northern Mexico, east to Florida, and north to southern Missouri and Oklahoma. Ungnadia speciosa Endl. (Mexican-buckeye, Sapindaceae) is a shrub or small tree found in woodlands and savannas of central and western Texas, southern New Mexico and northern Mexico. In central Texas, both species are found in Juniperus ashei/Quercus virginiana woodlands or savannas or also at low density in inter-canopy grassland gaps or patches. Environmental conditions in this area are stressful because of shallow soils, high summer temperatures, and inconsistent low rainfall. Currently, both species have a low density in these areas, and Ulmus crassifolia is usually a tree, while Ungnadia speciosa is a woody understory shrub. This study suggests U. crassifolia and U. speciosa are tolerant or intermediate species, with juveniles starting in shade. Maximum photosynthetic rate (A<sub>max</sub>), dark respiration (R<sub>d</sub>), intercellular CO<sub>2</sub>, light saturation (L<sub>sp</sub>) and water use efficiency significantly increased when light levels and CO<sub>2</sub> concentrations were elevated for both species, but not when temperatures were elevated. Stomatal conductance decreased when the CO<sub>2</sub> concentration doubled, but there were few effects from elevated temperature. These findings suggest that U. speciosa and U. crassifolia should be more common and imply that they will have a higher density in a future high CO<sub>2</sub> environment.展开更多
Phenol is a common industrial chemical produced and transported worldwide largely.Therefore,accidental spillage of phenol in the ocean causes an increasing concern.Microalgae are promising to remove phenol from marine...Phenol is a common industrial chemical produced and transported worldwide largely.Therefore,accidental spillage of phenol in the ocean causes an increasing concern.Microalgae are promising to remove phenol from marine waters.However,temperature and light intensity are two main factors that markedly influence biodegradation in marine environments.In this study,a marine golden alga Isochrysis galbana is selected to research the removal of phenol under different temperatures(10-30℃)and light intensities(0-240μmol/(m^2·s)).The results show that the most suitable temperature and light intensity for phenol removal are 20℃and 180μmol/(m2·s),respectively,and 100 mg/L of phenol can be completely removed by microalga in 24 h at these conditions.I.galbana can also remove phenol under dark and low-temperature conditions.The removal of phenol by I.galbana at diverse temperatures and light intensities conform to first-order kinetics,and the process under dark conditions conform to zero-order kinetics.Thus,I.galbana can be used in the in-situ bioremediation of polluted seawater by phenol.展开更多
Based on research results on the impacts of solar light,seawater temperature,and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage,we discussed the order of influence of...Based on research results on the impacts of solar light,seawater temperature,and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage,we discussed the order of influence of these factors.By clarifying the mechanisms and processes of the impacts by these factors,we have determined the rising order of the importance as solar light,seawater temperature,and nutrient silicon (Si).Therefore,for human interests in sustaining economic development,the first thing to be considered is the input of nutrient Si into the ocean,followed by seawater temperature change.展开更多
The dynamics of chlorophyll content, leaf area and photosynthesis of cucumber seedlings were studied under sole stress of two low temperatures and low light intensity as well as combined stresses of low light intensit...The dynamics of chlorophyll content, leaf area and photosynthesis of cucumber seedlings were studied under sole stress of two low temperatures and low light intensity as well as combined stresses of low light intensity and the two low temperatures. The results showed that low light intensity reduced sensitivity of cucumber to low temperature and improved chlorophyll content, leaf area and chlorophyll fluorescence quantum yield. The photosynthesis rate was reduced under low light intensity. The intensity of light played the leading role in growth of cucumber under the low temperature condition, while the low temperature played the leading role under the critical low temperature condition. There were differences in reaction to light and temperature among different varieties. The tolerance to low temperature and low light intensity was not always synergetic for the same cucumber variety.展开更多
It is essential to investigate the light field camera parameters for the accurate flame temperature measurement because the sampling characteristics of the flame radiation can be varied with them. In this study, novel...It is essential to investigate the light field camera parameters for the accurate flame temperature measurement because the sampling characteristics of the flame radiation can be varied with them. In this study, novel indices of the light field camera were proposed to investigate the directional and spatial sampling characteristics of the flame radiation. Effects of light field camera parameters such as focal length and magnification of the main lens, focal length and magnification of the microlens were investigated. It was observed that the sampling characteristics of the flame are varied with the different parameters of the light field camera. The optimized parameters of the light field camera were then proposed for the flame radiation sampling. The larger sampling angle(23 times larger) is achieved by the optimized parameters compared to the commercial light field camera parameters. A non-negative least square(NNLS) algorithm was used to reconstruct the flame temperature. The reconstruction accuracy was also evaluated by the optimized parameters. The results suggested that the optimized parameters can provide higher reconstruction accuracy for axisymmetric and non-symmetric flame conditions in comparison to the commercial light field camera.展开更多
The effects of acetylsalicylic acid (ASA), CaCl2, and ASA + CaCl2 on the photosynthetic apparatus and antioxidant enzyme activities were investigated in chrysanthemum Jinba (a cut flower cultivar) under low tempe...The effects of acetylsalicylic acid (ASA), CaCl2, and ASA + CaCl2 on the photosynthetic apparatus and antioxidant enzyme activities were investigated in chrysanthemum Jinba (a cut flower cultivar) under low temperature stress with low light (TL stress) (16/12℃, day/night, PFD 100 μmol m^-2 s-1). The results showed that under TL stress, the net photosynthesis rate (Pn), carboxylation efficiency (CE), apparent quantum yield (AQY), maximal photochemical efficiency (Fv/Fm) of PSII, quantum yield of PSII electron transport (ФPSII), and photochemical quenching (qP) of the chrysanthemum leaves in all treatments were significantly decreased, but the decreases were alleviated by ASA, CaCl2, and ASA + CaCl2 treatments compared with the controls. The alleviating effect of ASA + CaCI2 was better than either ASA or CaCl2 single treatment. Moreover, the ASA + CaCl2 treatment highly improved the chlorophyll content, relatively improved the number and size of chloroplast and starch grain in the leaves of chrysanthemum plants compared with ASA and CaCl2 treatments. It was indicated that ASA and/or CaCI2 could regulate the photosynthetic functions in the leaves of chrysanthemum plants to enhance the resistance against TL stress. On the other hand, reduction in relative conductance rate implied that ASA and/ or CaCl2 could protect from membrane injury in leaves of chrysanthemum plants. The activities of SOD, POD, and CAT in the treated leaves of chrysanthemum were increased as compared with the controls. It was suggested that ASA and/or CaCl2 had positive regulation effects on the defence enzyme activities in chrysanthemum leaves which could protect the photosynthetic apparatus to a certain degree under the TL stress. In brief, the treatment of ASA together with CaCl2 was better for chrysanthemum plants to adapt TL stress than single ASA or CaCl2 treatments.展开更多
Water can acquire a kinetic activity, which is attributed to the absorption of an environmental force termed KELEA (kinetic energy limiting electrostatic attraction). This activity can lead to increased volatility of ...Water can acquire a kinetic activity, which is attributed to the absorption of an environmental force termed KELEA (kinetic energy limiting electrostatic attraction). This activity can lead to increased volatility of the water that can be measured as the progressive weight loss in closed but not completely sealed containers. It has been proposed that KELEA is a natural force required to prevent the fusion and possible annihilation of electrostatically attracted opposite electrical charges. As such, it may be especially available where there is a convergence of force fields of opposing electrical charges. At least conceptually, this may arise with facing light sources with centrally directed light beams. An oscillating attraction and release of KELEA may be facilitated by repetitively disrupting the light paths using an overhead flashing light source. This paper reports on preliminary studies that are based on this premise. Although not proving the premise, the reported experiments do indicate a simple method for activating water. Moreover, the described procedure should allow for further exploration of the underlying mechanism of water activation. The procedure involves the use of four, diagonally placed regular LED traffic lights, with an overhead strobe light. The volatility of water samples in closed but not completely sealed glass vials placed within the lighted area significantly increases in a manner that persists well beyond the periods of light exposure. The paper further shows that activated water can indirectly lead to the activation of nearby water. The reported observations are of both practical and theoretical importance.展开更多
Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habit...Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habitats and high altitudes.Specifically,we examined the effects of cold stratification,light,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)increased significantly,suggesting that P.beesiana has type 3 non-deep physiological dormancy.The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks.Cold-stratified seeds incubated at fluctuating temperatures(especially at 15/5℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).Seeds had a strict light requirement at all temperatures,even after experiencing cold stratification;however,the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light.Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface,thus avoiding seedling death by freezing,inundation and/or germination deep in the soil.展开更多
Native orchid species of Singapore in their natural conditions experience stress from high irradiance, high temperatures and periods of extended low rainfall, which impact orchid plant physiology and lead to reduced g...Native orchid species of Singapore in their natural conditions experience stress from high irradiance, high temperatures and periods of extended low rainfall, which impact orchid plant physiology and lead to reduced growth and productivity. In this study, it was found that there was a reduction in photochemical efficiency of photosystem II (PSII) in 6 native orchid species under high light (HL) and Bulbophyllum membranaceum under low light (LL). There was chronic photoinhibition in these 6 orchid species over a period of 3 months after transplanting onto the tree trunks without watering and fertilization, especially in Coelogynes mayeriana and Bulbophyllum membranaceum under both HL and LL. This chronic photoinhibition caused by sustained period of water deficit in their natural conditions was later reversed by natural re-watering conditions from higher rainfall. These results indicate that water deficit has a greater impact on photosynthetic light utilization efficiency than excess light. The present study also showed that after natural rewatering, relative water content (RWC) of leaves and pseudobulbs generally increased. During the natural re-watering, total leaf area also gradually increased and reached maximum expansion after 7 weeks under both HL and LL, with some exceptions due to leaf abscission or decline in total leaf area, possibly a strategy for water conservation.展开更多
It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentra...It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>展开更多
In this paper, artificial intelligence image recognition technology is used to improve the recognition rate of individual domestic fish and reduce the recognition time, aiming at the problem that it is difficult to ea...In this paper, artificial intelligence image recognition technology is used to improve the recognition rate of individual domestic fish and reduce the recognition time, aiming at the problem that it is difficult to easily observe the species and growth of domestic fish in the underwater non-uniform light field environment. First, starting from the image data collected by polarizing imaging technology, this paper uses subpixel convolution reconstruction to enhance the image, uses image translation and fill technology to build the family fish database, builds the Adam-Dropout-CNN (A-D-CNN) network model, and its convolution kernel size is 3 × 3. The maximum pooling was used for downsampling, and the discarding operation was added after the full connection layer to avoid the phenomenon of network overfitting. The adaptive motion estimation algorithm was used to solve the gradient sparse problem. The experiment shows that the recognition rate of A-D-CNN is 96.97% when the model is trained under the domestic fish image database, which solves the problem of low recognition rate and slow recognition speed of domestic fish in non-uniform light field.展开更多
The extracellular dissolved organic, carbon (DOC) and algal cell particlutate organiccarbon (POC) of a marine nanoplanktonic diatom Chaetoceros sp. were determined in this study. Thedaily rhythm and the influence of l...The extracellular dissolved organic, carbon (DOC) and algal cell particlutate organiccarbon (POC) of a marine nanoplanktonic diatom Chaetoceros sp. were determined in this study. Thedaily rhythm and the influence of light and temperature on the production rate of DOC and POC were stud-ied by growing the diatom under different laboratory controlled conditions of light and temperature. Theresults showed that the production of DOC and POC varied with light and temperature and were generallyhigher at daytime than at night. Under culture conditions of 24L:0D light cycle and 3500 lx light intensi-ty, the DOC and POC reached maximum (DOC: 17. 27 mgC/L; POC: 103. 10 mgC/L). While展开更多
The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was stud...The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.展开更多
Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorologica...Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorological factors for seedcotton biomass per boll with respect to boll positions. Field experiments were conducted using two cultivars of Kemian 1 and Sumian 15 with three planting dates of 25 April (mean daily temperature (MDT) was 28.0 and 25.4°C in 2010 and 2011, respectively), 25 May (MDT was 22.5 and 21.2°C in 2010 and 2011, respectively), and 10 Jun (MDT was 18.7 and 17.9°C in 2010 and 2011, respectively), and under three shading levels (crop relative light rates (CRLR) were 100, 80, and 60%) during 2010 and 2011 cotton boll development period (from anthesis to boll open stages). The main meteorological factors (temperature and light) affected seedcotton biomass per boll differently among different boll positions and cultivars. Mean daily radiation (MDR) affected seedcotton biomass per boll at all boll positions, except fruiting branch 2 (FB2) fruting node 1 (FN1). However, its influence was less than temperature factors, especially growing degree-days (GDD). Optimum mean daily maximum temperature (MDTmax) for seedcotton biomass per boll at FB11FN3 was 29.9-32.4°C, and the optimum MDR at aforementioned position was 15.8-17.5 MJ m-2. Definitely, these results can contribute to future cultural practices such as rational cultivars choice and distribution, simplifying field managements and mechanization to acquire more efficient and economical cotton management.展开更多
[Objective] The study aimed to discuss the influence of light and temperature factors on biomass accumulation of winter wheat at each growth stage and changes in biomass of each organ. [Method] Based on the observatio...[Objective] The study aimed to discuss the influence of light and temperature factors on biomass accumulation of winter wheat at each growth stage and changes in biomass of each organ. [Method] Based on the observation data from Xifeng Agrometeorological Experiment Station of Gansu Province, including phenophase and yield factors of winter wheat in 1981 -2008, biomass at three-leaves, overwintering, jointing, heading, milky maturity, and maturity stages in 1995 -2008, and meteorological data in 1995 -2008, the variation patterns of the biomass accumulation and the influence of TEP (thermal effectiveness photosynthetically active radiation) on the biomass of winter wheat at every growth stage were ana- lyzed. [Result] The biomass accumulation of winter wheat in the whole growth period presented "S" curve, with the maximum value from heading to milky maturity stage. Since 1981, TEP from heading to milky maturity stage increased with a rate of 3. 314 MJ/(m2 · a), and the changing curves of TEP at other stages were like parable curves. TEP from turning green to jointing stage and from milky maturity to maturity stage had a higher value in the 1990s and a lower val.ue in the 1980s and early 21st century, while that from jointing to heading stage had a lower value in the 1990s but a higher value in the 1980s and early 21st century. There was a significant correlation between TEP at each growth stage and the actual yield. LAI (leaf area index) at each development stage also had a significant correlation with the utilization rate of TEP at corresponding stage. When LAI at jointing and heading stages increased by I, the utilization rate of TEP correspondingly increased by 0. 049 and 0.259 g/MJ respectively. [ Conclusion] The research could provide theoretical references for the scientific planting and management of winter wheat in future. Key words Light and temperature factors; Winter wheat; Biomass; Influence; China展开更多
In view of domestic scientific and technological achievements at present,real-time control circuit for greenhouse temperature and light intensity has been designed in line with the principle of cost saving and easy co...In view of domestic scientific and technological achievements at present,real-time control circuit for greenhouse temperature and light intensity has been designed in line with the principle of cost saving and easy control.With advanced temperature sensor and light sensor applied to measure the temperature and light intensity,an execution unit is controlled by single-chip microcomputer(SCM)to regulate the temperature and light intensity,creating a hardware design scheme and software design idea.In case of high temperature and high light intensity in greenhouse,the sunshade net will be put down and the blower will be started automatically;in case of low temperature and light intensity,the sunshade net will be folded up and the heating valve will be turned up automatically.In this way,the temperature and light intensity in greenhouse will be controlled within the designed range.展开更多
基金supported by the Natural Science Foundation of Zhejiang Province(No.LY23D060003)the Key Program of Science and Technology Innovation in Ningbo(2021Z114,2023Z118)sponsored by K.C.Wong Magna Fund in Ningbo University.
文摘In order to study the complex effects of photoperiod,temperature,and light intensity on the spore maturation and release number of Ulva prolifera,we cultured thalli segment(2–3 mm)under three different photoperiods(L:D=12:12,14:10 and 10:14),temperature(15℃(LT),25℃(MT)and 30℃(HT))and light intensity(100,200 and 400μmol m^(−2)s^(−1),noted as LL,ML and HL,respectively)conditions.Then the maturation time,spore release number and chlorophyll fluorescence were analyzed.The results suggested that:1)The spore maturation time was accelerated by higher temperature or higher light intensity from 62 h to 36 h,and changes in day length accelerated the spore maturation to a certain extent as compared with 12:12 light/dark cycle;2)Higher light intensity significantly decreased the chlorophyll fluorescence(Fv′/Fm′,NPQ,rETRmax andα)of the mature reproductive segment under 30℃with 12:12 light/dark cycle.But when in the other photoperiods(10:14 and 14:10 conditions),the inhibitory effects of high light intensity were alleviated significantly;3)The optimum condition for the spore maturation and release was 12:12 light/dark cycle,25℃,400μmol m^(−2)s^(−1),with both shorter and longer photoperiod reducing the spore release number;4)Higher light intensity significantly increased the spore release number under 25℃,but these effects were alleviated by 30℃treatment.This study is the first attempt to elucidate the coincidence effects of photoperiod,temperature and light intensity on the reproduction of Ulva,which would help to reveal the mechanism of the rapid proliferation of green tide.
基金Supported by the PetroChina Science and Technology Project(2023ZG18).
文摘The miscibility of flue gas and different types of light oils is investigated through slender-tube miscible displacement experiment at high temperature and high pressure.Under the conditions of high temperature and high pressure,the miscible displacement of flue gas and light oil is possible.At the same temperature,there is a linear relationship between oil displacement efficiency and pressure.At the same pressure,the oil displacement efficiency increases gently and then rapidly to more than 90% to achieve miscible displacement with the increase of temperature.The rapid increase of oil displacement efficiency is closely related to the process that the light components of oil transit in phase state due to distillation with the rise of temperature.Moreover,at the same pressure,the lighter the oil,the lower the minimum miscibility temperature between flue gas and oil,which allows easier miscibility and ultimately better performance of thermal miscible flooding by air injection.The miscibility between flue gas and light oil at high temperature and high pressure is more typically characterized by phase transition at high temperature in supercritical state,and it is different from the contact extraction miscibility of CO_(2) under conventional high pressure conditions.
基金supported by the National Natural Science Foundation of China (32188102 and 31901481)。
文摘Chlorophyll,a green pigment in photosynthetic organisms,is generated by two distinct biochemical pathways,the tetrapyrrole biosynthetic pathway(TBP) and the methylerythritol 4-phosphate(MEP)pathway.MEP is one of the pathways for isoprenoid synthesis in plants,with 4-hydroxy-3-methylbut-2-enyl diphosphate reductase(HDR) catalyzing its last step.In this study,we isolated a greenrevertible yellow leaf mutant gry3 in rice and cloned the GRY3 gene,which encodes a HDR participating in geranylgeranyl diphosphate(GGPP) biosynthesis in chloroplast.A complementation experiment confirmed that a missense mutation(C to T) in the fourth exon of LOC_Os03g52170 causes the gry3 phenotype.Under high temperature and high light,transcript and protein abundances of GRY3 were reduced in the gry3 mutant.Transcriptional expression of chlorophyll biosynthesis,chloroplast development,and genes involved in photosynthesis were also affected.Excessive reactive oxygen species accumulation,cell death,and photosynthetic proteins degradation were occurred in the mutant.The content of GGPP was reduced in gry3 compared with Nipponbare,resulting in a stoichiometric imbalance of tetrapyrrolic chlorophyll precursors.These results shed light on the response of chloroplast biogenesis and maintenance in plants to high-temperature and high-light stress.
文摘Ulmus crassifolia Nutt. (Cedar elm, Ulmaceae) is a tree found in central and east Texas, northern Mexico, east to Florida, and north to southern Missouri and Oklahoma. Ungnadia speciosa Endl. (Mexican-buckeye, Sapindaceae) is a shrub or small tree found in woodlands and savannas of central and western Texas, southern New Mexico and northern Mexico. In central Texas, both species are found in Juniperus ashei/Quercus virginiana woodlands or savannas or also at low density in inter-canopy grassland gaps or patches. Environmental conditions in this area are stressful because of shallow soils, high summer temperatures, and inconsistent low rainfall. Currently, both species have a low density in these areas, and Ulmus crassifolia is usually a tree, while Ungnadia speciosa is a woody understory shrub. This study suggests U. crassifolia and U. speciosa are tolerant or intermediate species, with juveniles starting in shade. Maximum photosynthetic rate (A<sub>max</sub>), dark respiration (R<sub>d</sub>), intercellular CO<sub>2</sub>, light saturation (L<sub>sp</sub>) and water use efficiency significantly increased when light levels and CO<sub>2</sub> concentrations were elevated for both species, but not when temperatures were elevated. Stomatal conductance decreased when the CO<sub>2</sub> concentration doubled, but there were few effects from elevated temperature. These findings suggest that U. speciosa and U. crassifolia should be more common and imply that they will have a higher density in a future high CO<sub>2</sub> environment.
基金Supported by the National Marine Hazard Mitigation Service,Ministry of Natural Resource of the People’s Republic of China through its Commissioned Research Scheme(No.2018AA019)。
文摘Phenol is a common industrial chemical produced and transported worldwide largely.Therefore,accidental spillage of phenol in the ocean causes an increasing concern.Microalgae are promising to remove phenol from marine waters.However,temperature and light intensity are two main factors that markedly influence biodegradation in marine environments.In this study,a marine golden alga Isochrysis galbana is selected to research the removal of phenol under different temperatures(10-30℃)and light intensities(0-240μmol/(m^2·s)).The results show that the most suitable temperature and light intensity for phenol removal are 20℃and 180μmol/(m2·s),respectively,and 100 mg/L of phenol can be completely removed by microalga in 24 h at these conditions.I.galbana can also remove phenol under dark and low-temperature conditions.The removal of phenol by I.galbana at diverse temperatures and light intensities conform to first-order kinetics,and the process under dark conditions conform to zero-order kinetics.Thus,I.galbana can be used in the in-situ bioremediation of polluted seawater by phenol.
基金Supported by the Knowledge Innovation Project of Chinese Academy of Sciences (No.KZCX 2-207)Zhejiang Bureau of Science and Technology (No.2007C23075)
文摘Based on research results on the impacts of solar light,seawater temperature,and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage,we discussed the order of influence of these factors.By clarifying the mechanisms and processes of the impacts by these factors,we have determined the rising order of the importance as solar light,seawater temperature,and nutrient silicon (Si).Therefore,for human interests in sustaining economic development,the first thing to be considered is the input of nutrient Si into the ocean,followed by seawater temperature change.
基金supported by the National Natural Science Foundation of China(39830230)Beijing Natural Science Foundation(6O11002).
文摘The dynamics of chlorophyll content, leaf area and photosynthesis of cucumber seedlings were studied under sole stress of two low temperatures and low light intensity as well as combined stresses of low light intensity and the two low temperatures. The results showed that low light intensity reduced sensitivity of cucumber to low temperature and improved chlorophyll content, leaf area and chlorophyll fluorescence quantum yield. The photosynthesis rate was reduced under low light intensity. The intensity of light played the leading role in growth of cucumber under the low temperature condition, while the low temperature played the leading role under the critical low temperature condition. There were differences in reaction to light and temperature among different varieties. The tolerance to low temperature and low light intensity was not always synergetic for the same cucumber variety.
基金supported by the National Natural Science Foundation of China(Grant Nos.51676044 and 51327803)the Social Development Project of Jiangsu Province,China(Grant No.BE20187053)+1 种基金the Postgraduate Research and Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX170081)China Scholarship Council
文摘It is essential to investigate the light field camera parameters for the accurate flame temperature measurement because the sampling characteristics of the flame radiation can be varied with them. In this study, novel indices of the light field camera were proposed to investigate the directional and spatial sampling characteristics of the flame radiation. Effects of light field camera parameters such as focal length and magnification of the main lens, focal length and magnification of the microlens were investigated. It was observed that the sampling characteristics of the flame are varied with the different parameters of the light field camera. The optimized parameters of the light field camera were then proposed for the flame radiation sampling. The larger sampling angle(23 times larger) is achieved by the optimized parameters compared to the commercial light field camera parameters. A non-negative least square(NNLS) algorithm was used to reconstruct the flame temperature. The reconstruction accuracy was also evaluated by the optimized parameters. The results suggested that the optimized parameters can provide higher reconstruction accuracy for axisymmetric and non-symmetric flame conditions in comparison to the commercial light field camera.
基金supported by the National Key Tech-nologies R&D Program of China during the 11th Five-Year-Plan period (2006BAD10B07)the Project for Returned Overseas Atudents to Start Research from Ministry of Education,China (33206)
文摘The effects of acetylsalicylic acid (ASA), CaCl2, and ASA + CaCl2 on the photosynthetic apparatus and antioxidant enzyme activities were investigated in chrysanthemum Jinba (a cut flower cultivar) under low temperature stress with low light (TL stress) (16/12℃, day/night, PFD 100 μmol m^-2 s-1). The results showed that under TL stress, the net photosynthesis rate (Pn), carboxylation efficiency (CE), apparent quantum yield (AQY), maximal photochemical efficiency (Fv/Fm) of PSII, quantum yield of PSII electron transport (ФPSII), and photochemical quenching (qP) of the chrysanthemum leaves in all treatments were significantly decreased, but the decreases were alleviated by ASA, CaCl2, and ASA + CaCl2 treatments compared with the controls. The alleviating effect of ASA + CaCI2 was better than either ASA or CaCl2 single treatment. Moreover, the ASA + CaCl2 treatment highly improved the chlorophyll content, relatively improved the number and size of chloroplast and starch grain in the leaves of chrysanthemum plants compared with ASA and CaCl2 treatments. It was indicated that ASA and/or CaCI2 could regulate the photosynthetic functions in the leaves of chrysanthemum plants to enhance the resistance against TL stress. On the other hand, reduction in relative conductance rate implied that ASA and/ or CaCl2 could protect from membrane injury in leaves of chrysanthemum plants. The activities of SOD, POD, and CAT in the treated leaves of chrysanthemum were increased as compared with the controls. It was suggested that ASA and/or CaCl2 had positive regulation effects on the defence enzyme activities in chrysanthemum leaves which could protect the photosynthetic apparatus to a certain degree under the TL stress. In brief, the treatment of ASA together with CaCl2 was better for chrysanthemum plants to adapt TL stress than single ASA or CaCl2 treatments.
文摘Water can acquire a kinetic activity, which is attributed to the absorption of an environmental force termed KELEA (kinetic energy limiting electrostatic attraction). This activity can lead to increased volatility of the water that can be measured as the progressive weight loss in closed but not completely sealed containers. It has been proposed that KELEA is a natural force required to prevent the fusion and possible annihilation of electrostatically attracted opposite electrical charges. As such, it may be especially available where there is a convergence of force fields of opposing electrical charges. At least conceptually, this may arise with facing light sources with centrally directed light beams. An oscillating attraction and release of KELEA may be facilitated by repetitively disrupting the light paths using an overhead flashing light source. This paper reports on preliminary studies that are based on this premise. Although not proving the premise, the reported experiments do indicate a simple method for activating water. Moreover, the described procedure should allow for further exploration of the underlying mechanism of water activation. The procedure involves the use of four, diagonally placed regular LED traffic lights, with an overhead strobe light. The volatility of water samples in closed but not completely sealed glass vials placed within the lighted area significantly increases in a manner that persists well beyond the periods of light exposure. The paper further shows that activated water can indirectly lead to the activation of nearby water. The reported observations are of both practical and theoretical importance.
基金the National Key R&D Program of China(2017YF0505200 to H.Sun)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA 20050203 to H.Sun)+1 种基金the Key Program of the National Natural Science Foundation of China(U1802232 to H.Sun)National Natural Science Foundation of China(grant 31700284 to D.L.Peng,31670206 to Z.M.Li and 31900185 to L.E.Yang)。
文摘Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habitats and high altitudes.Specifically,we examined the effects of cold stratification,light,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)increased significantly,suggesting that P.beesiana has type 3 non-deep physiological dormancy.The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks.Cold-stratified seeds incubated at fluctuating temperatures(especially at 15/5℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).Seeds had a strict light requirement at all temperatures,even after experiencing cold stratification;however,the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light.Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface,thus avoiding seedling death by freezing,inundation and/or germination deep in the soil.
文摘Native orchid species of Singapore in their natural conditions experience stress from high irradiance, high temperatures and periods of extended low rainfall, which impact orchid plant physiology and lead to reduced growth and productivity. In this study, it was found that there was a reduction in photochemical efficiency of photosystem II (PSII) in 6 native orchid species under high light (HL) and Bulbophyllum membranaceum under low light (LL). There was chronic photoinhibition in these 6 orchid species over a period of 3 months after transplanting onto the tree trunks without watering and fertilization, especially in Coelogynes mayeriana and Bulbophyllum membranaceum under both HL and LL. This chronic photoinhibition caused by sustained period of water deficit in their natural conditions was later reversed by natural re-watering conditions from higher rainfall. These results indicate that water deficit has a greater impact on photosynthetic light utilization efficiency than excess light. The present study also showed that after natural rewatering, relative water content (RWC) of leaves and pseudobulbs generally increased. During the natural re-watering, total leaf area also gradually increased and reached maximum expansion after 7 weeks under both HL and LL, with some exceptions due to leaf abscission or decline in total leaf area, possibly a strategy for water conservation.
文摘It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>
文摘In this paper, artificial intelligence image recognition technology is used to improve the recognition rate of individual domestic fish and reduce the recognition time, aiming at the problem that it is difficult to easily observe the species and growth of domestic fish in the underwater non-uniform light field environment. First, starting from the image data collected by polarizing imaging technology, this paper uses subpixel convolution reconstruction to enhance the image, uses image translation and fill technology to build the family fish database, builds the Adam-Dropout-CNN (A-D-CNN) network model, and its convolution kernel size is 3 × 3. The maximum pooling was used for downsampling, and the discarding operation was added after the full connection layer to avoid the phenomenon of network overfitting. The adaptive motion estimation algorithm was used to solve the gradient sparse problem. The experiment shows that the recognition rate of A-D-CNN is 96.97% when the model is trained under the domestic fish image database, which solves the problem of low recognition rate and slow recognition speed of domestic fish in non-uniform light field.
基金This work was supported by the MEE Key Laboratory of Ministry of Education,Xiamen University(Grant No.MEE9903)and by Ministry of Education Foundation for University Key Teacher
文摘The extracellular dissolved organic, carbon (DOC) and algal cell particlutate organiccarbon (POC) of a marine nanoplanktonic diatom Chaetoceros sp. were determined in this study. Thedaily rhythm and the influence of light and temperature on the production rate of DOC and POC were stud-ied by growing the diatom under different laboratory controlled conditions of light and temperature. Theresults showed that the production of DOC and POC varied with light and temperature and were generallyhigher at daytime than at night. Under culture conditions of 24L:0D light cycle and 3500 lx light intensi-ty, the DOC and POC reached maximum (DOC: 17. 27 mgC/L; POC: 103. 10 mgC/L). While
基金the National Natural Science Foundation of China (39830230) Beijing Natural Science Foundation (6011002).
文摘The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.
基金supported by the National Natural Science Foundation of China (31471444,31401327)the Special Fund for Agro-scientific Research in the Public Interest of China (Impact of Climate Change on Agriculture Production,201203096)the Jiangsu Overseas Research and Training Program for University Prominent Young and Middle-aged Teachers and President,China (2016)
文摘Cotton growth and development are determined and influenced by cultivars, meteorological conditions, and management practices. The objective of this study was to quantify the optimum of temperature-light meteorological factors for seedcotton biomass per boll with respect to boll positions. Field experiments were conducted using two cultivars of Kemian 1 and Sumian 15 with three planting dates of 25 April (mean daily temperature (MDT) was 28.0 and 25.4°C in 2010 and 2011, respectively), 25 May (MDT was 22.5 and 21.2°C in 2010 and 2011, respectively), and 10 Jun (MDT was 18.7 and 17.9°C in 2010 and 2011, respectively), and under three shading levels (crop relative light rates (CRLR) were 100, 80, and 60%) during 2010 and 2011 cotton boll development period (from anthesis to boll open stages). The main meteorological factors (temperature and light) affected seedcotton biomass per boll differently among different boll positions and cultivars. Mean daily radiation (MDR) affected seedcotton biomass per boll at all boll positions, except fruiting branch 2 (FB2) fruting node 1 (FN1). However, its influence was less than temperature factors, especially growing degree-days (GDD). Optimum mean daily maximum temperature (MDTmax) for seedcotton biomass per boll at FB11FN3 was 29.9-32.4°C, and the optimum MDR at aforementioned position was 15.8-17.5 MJ m-2. Definitely, these results can contribute to future cultural practices such as rational cultivars choice and distribution, simplifying field managements and mechanization to acquire more efficient and economical cotton management.
基金Supported by the Arid Meteorology Foundation of Institute of Arid Meteorology,China Meteorological Administration(IAM200803)
文摘[Objective] The study aimed to discuss the influence of light and temperature factors on biomass accumulation of winter wheat at each growth stage and changes in biomass of each organ. [Method] Based on the observation data from Xifeng Agrometeorological Experiment Station of Gansu Province, including phenophase and yield factors of winter wheat in 1981 -2008, biomass at three-leaves, overwintering, jointing, heading, milky maturity, and maturity stages in 1995 -2008, and meteorological data in 1995 -2008, the variation patterns of the biomass accumulation and the influence of TEP (thermal effectiveness photosynthetically active radiation) on the biomass of winter wheat at every growth stage were ana- lyzed. [Result] The biomass accumulation of winter wheat in the whole growth period presented "S" curve, with the maximum value from heading to milky maturity stage. Since 1981, TEP from heading to milky maturity stage increased with a rate of 3. 314 MJ/(m2 · a), and the changing curves of TEP at other stages were like parable curves. TEP from turning green to jointing stage and from milky maturity to maturity stage had a higher value in the 1990s and a lower val.ue in the 1980s and early 21st century, while that from jointing to heading stage had a lower value in the 1990s but a higher value in the 1980s and early 21st century. There was a significant correlation between TEP at each growth stage and the actual yield. LAI (leaf area index) at each development stage also had a significant correlation with the utilization rate of TEP at corresponding stage. When LAI at jointing and heading stages increased by I, the utilization rate of TEP correspondingly increased by 0. 049 and 0.259 g/MJ respectively. [ Conclusion] The research could provide theoretical references for the scientific planting and management of winter wheat in future. Key words Light and temperature factors; Winter wheat; Biomass; Influence; China
文摘In view of domestic scientific and technological achievements at present,real-time control circuit for greenhouse temperature and light intensity has been designed in line with the principle of cost saving and easy control.With advanced temperature sensor and light sensor applied to measure the temperature and light intensity,an execution unit is controlled by single-chip microcomputer(SCM)to regulate the temperature and light intensity,creating a hardware design scheme and software design idea.In case of high temperature and high light intensity in greenhouse,the sunshade net will be put down and the blower will be started automatically;in case of low temperature and light intensity,the sunshade net will be folded up and the heating valve will be turned up automatically.In this way,the temperature and light intensity in greenhouse will be controlled within the designed range.