温室甜椒叶面积指数形成模拟模型

叶面积指数是光合作用驱动的作物生长模型以及冠层蒸腾模型所需的重要作物参数,温度和辐射是影响叶片生长的重要环境因子.通过不同定植期、不同品种、不同地点的试 验,定量分析了温室甜椒出叶数、叶片长度和叶面积指数与温度和辐射的关系,构建了温室 甜椒叶面积模型,并利用独立的试验资料对模型进行了检验.结果表明：甜椒出叶数与出苗 后累积辐热积呈指数函数关系;叶片长度与出叶后累积辐热积呈负指数函数关系;甜椒出叶 数、叶片长度和叶面积指数的模拟结果与实测值之间的决定系数R²分别为0.94、0.89、0.93,其回归估计标准误RMSE分别为3.4、2.15 cm、0.15.该模型能够利用气温、辐射、 种植密度和出苗日期准确地预测温室甜椒叶面积指数动态,且模型参数少、实用性强,可以为温室甜椒生长模型和蒸腾模型提供必需的叶面积指数动态信息.     

干湿交替格局下黄土高原小麦田土壤呼吸的温湿度模型

全球气候变化的直接后果是气温升高,同时还可能引起强降雨增多和干旱频发,形成干湿交替的格局.土壤呼吸在全球变化过程中发挥着重要作用.以黄土高原沟壑区小麦田土壤为研究对象,采用3个全自动多通量箱以及相应的气象监测系统,对土壤呼吸和环境因子全天候连续测定,利用已有的单因子模型、双因子模型对测定的土壤呼吸与气温和湿度的关系进行了拟合,通过优化,根据实际情况提出E-Q(exponential-quadratic)模型.结果表明:(1)干湿交替格局下,基于气温的单因子模型(指数模型,幂函数模型和线性模型)不适合模拟土壤呼吸;(2)基于土壤湿度的单因子模型中,二次曲线模型最适合模拟干湿交替格局下土壤呼吸的响应情况;(3)基于气温和土壤湿度的双因子模型中,E-Q模型SR=aebT(c+dW+fW2)g,既能反映土壤呼吸随气温的正向指数变化,又能表现土壤湿度对土壤呼吸的双向调节作用,解释了土壤呼吸73.05%的变化情况,比其他双因子模型和单因子模型更能有效描述干湿交替情况下土壤呼吸对气温和土壤湿度协同变化的响应特征.     

湿地生态系统土壤温度对气温的响应特征及对CO2排放的影响

通过2年的野外定位观测,研究了沼泽湿地土壤温度对气温变化的响应特征,以及土壤温度对沼泽湿地植物 土壤系统CO₂排放的影响,并对CO₂排放的季节性变化进行模拟计算.结果表明,随融冻作用开始,沼泽湿地土壤温度对气温变化的响应强度不断增大,根层土壤温度与气温间呈显著指数关系（R²=0.94,P<0.01）,但不同深度土壤温度对气温变化的响应强度存在一定的差异,表现为随土壤深度的增加,二者之间的相关系数变小,土壤温度对气温的响应强度减弱.沼泽湿地植物 土壤系统CO₂排放与根层土壤温度有关,二者呈显著指数相关关系（R²=0.84,P<0.01）,利用模型模拟计算出沼泽湿地2003年生长季植物 土壤系统CO₂排放通量平均值为664.5±213.9 mg·m^-2·h^-1,野外定位观测值为634.0±227.7 mg·m^-2·h^-1,二者之间差值不大,表明利用此方法可以对沼泽湿地生长季CO₂排放进行估算.     

黄土高原四种人工植物群落土壤呼吸季节变化及其影响因子

以黄土高原侧柏、柠条、沙棘和油松人工植物群落为对象,土壤呼吸日动态和季节变化及其与环境因子之间的关系,结果表明:4种植物群落土壤呼吸速率具有典型的日变化和季节变化模式, 4种群落中,以侧柏6月土壤呼吸日变幅最大,沙棘6月土壤呼吸日变幅最小,大部分群落不同月份最大土壤呼吸与最小土壤呼吸倍数在1.1～1.6之间.4种群落中,以柠条土壤呼吸季节变幅最大,侧柏最小,最大土壤呼吸与最小土壤呼吸的倍数为1.5～2.2倍之间.同一植物类型土壤呼吸具有明显的季节变化特征,其具体变化趋势因植物类型而异.4种植物群落土壤呼吸速率与土壤和大气温度以及土壤含水量的关系在不同季节表现为不同的关系,其中侧柏和柠条土壤呼吸与土壤温度均呈乘幂关系,与大气温度为指数关系.沙棘土壤呼吸与土壤温度和大气温度均为乘幂关系,油松土壤呼吸与土壤温度和大气温度均为线性关系.这表明土壤呼吸与土壤和大气温度之间的关系及其紧密程度因植被类型而异.综合分析表明,同一气候区相同环境因子对不同植物群落土壤呼吸的影响作用不同,且因其自身具有明显的季节变化,从而导致对土壤呼吸的调控作用也具有明显的季节变异模式.     

云南小中甸地区丽江云杉径向生长对气候变化的响应

丽江云杉原始林是云南省香格里拉县小中甸地区的主要森林类型.本文采用树轮年代学的方法分析了丽江云杉年轮宽度对气候变化的响应;选取相对保守的结果负指数曲线或线性回归拟合生长趋势建立年表,进行了不同时间尺度的气候因素与差值年表(RES)序列的相关及响应函数分析,并利用特征年分析了产生宽窄年轮的原因.结果表明:研究区丽江云杉的径向生长与温度升高在1990-2008年存在一定的“分离现象”;上一生长季的水热状况是限制丽江云杉当年生长的主要气候因子,特别是上年7月的气温对当年径向生长具有负反馈作用,而上年7月的充足降水则促进当年的径向生长;上年生长季温度与降水变化的相反趋势是导致宽窄年轮形成的主要原因;丽江云杉的生长对帕尔默干旱指数(PDSI)的变化不敏感.     

The group postural behaviour of growing pigs in relation to air velocity,air and floor temperature

In three experiments with 6 piglets each (3 males, 3 females), given access to a pen with 4 plates having different surface temperatures and an air-velocity gradient, the group postural behaviour was recorded and analyzed.The results indicate that temperature control of the floor surface can realize the preferred comfort zone of growing pigs, as a function of age and air temperature.In the case of a constant floor temperature which was higher than the air temperature, as a function of age the pigs preferred a lying area with an enhanced air velocity (0.3 m s⁻¹) when the air temperature was 14–25°C.Hence, the animals' preference for a well-defined combination of air and floor temperature, as well as of air velocity, can be used as a trigger within the engineering and control system of the house environment to avoid behaviour-related problems.     

温度、光辐射及水分对温室甜瓜幼苗干物质积累与分配的影响及其模拟模型

利用分期播种法和灌溉上限法,研究了温度、光辐射和水分等环境因子对温室甜瓜幼苗植株干物质积累与分配的影响,并基于积温学原理,综合环境其他因子,模拟建立了甜瓜幼苗受有效积温、日温差积累、光辐射积累等多因子驱动的干物质积累与分配模型．结果表明：周年不同播期,随着有效积温、光辐射积累及不同灌溉水分上限的变化,甜瓜幼苗期植株干物质积累和分配分别呈指数函数和二次抛物线函数变化,但不同播期及水分处理函数常数不同．综合分析认为,干物质积累和分配模型分别为有效积温驱动下的指数函数和二次抛物线函数,常数项均由日温差积累和光辐射积累驱动,它们之间为一次函数关系．验证结果表明,该模型能较为真实、客观地模拟植株干物质积累与分配变化过程,对甜瓜苗期生长分析与生产管理具有应用价值．     

Reduction of metabolic rate and thermoregulation during daily torpor

Physiological mechanisms causing reduction of metabolic rate during torpor in heterothermic endotherms are controversial. The original view that metabolic rate is reduced below the basal metabolic rate because the lowered body temperature reduces tissue metabolism has been challenged by a recent hypothesis which claims that metabolic rate during torpor is actively downregulated and is a function of the differential between body temperature and ambient temperature, rather than body temperature per se. In the present study, both the steady-state metabolic rate and body temperature of torpid stripe-faced dunnarts, Sminthopsis macroura (Dasyuridae: Marsupialia), showed two clearly different phases in response to change of air temperature. At air temperatures between 14 and 30°C, metabolic rate and body temperature decreased with air temperature, and metabolic rate showed an exponential relationship with body temperature (r ²=0.74). The Q ₁₀ for metabolic rate was between 2 and 3 over the body temperature range of 16 to 32°C. The difference between body temperature and air temperature over this temperature range did not change significantly, and the metabolic rate was not related to the difference between body temperature and air temperature (P=0.35). However, the apparent conductance decreased with air temperature. At air temperatures below 14°C, metabolic rate increased linearly with the decrease of air temperature (r ²=0.58) and body temperature was maintained above 16°C, largely independent of air temperature. Over this air temperature range, metabolic rate was positively correlated with the difference between body temperature and air temperature (r ²=0.61). Nevertheless, the Q ₁₀ for metabolic rate between normothermic and torpid thermoregulating animals at the same air temperature was also in the range of 2–3. These results suggest that over the air temperature range in which body temperature of S. macroura was not metabolically defended, metabolic rate during daily torpor was largely a function of body temperature. At air temperatures below 14°C, at which the torpid animals showed an increase of metabolic rate to regulate body temperature, the negative relationship between metabolic rate and air temperature was a function of the differential between body temperature and air temperature as during normothermia. However, even in thermoregulating animals, the reduction of metabolic rate from normothermia to torpor at a given air temperature can also be explained by temperature effects.Abbreviations BM body mass - BMR basal metabolic rate - C apparent conductance - MR metabolic rate - RMR resting metabolic rate - RQ respiratory quotient - T _a air temperature - T _b body temperature - T _lc lower critical temperature - T _tc critical air temperature during torpor - TMR metabolic rate during torpor - TNZ thermoneutral zone - T difference between body temperature and air temperature - VO₂ rate of oxygen consumption     

Dehydration Kinetics of Embryonic Axes from Desiccation-sensitive Seeds:An Assessment of Descriptive Models

The response of desiccation-sensitive plant tissues to dehydration is significantly affected by dehydration conditions, particularly the rate of drying. Consequently it is important to be able to quantify drying rate. The aim of the study was to assess two models that have been proposed to describe drying kinetics, and thus to provide a quantification of non-linear drying rates, of embryonic axes excised from recalcitrant seeds. These models are an exponential drying time course, and a modified inverse relationship, respectively. For the six species investigated here the inverse function was generally found to fit drying data better than the exponential function under both rapid and slow drying conditions, and so is recommended. The rate of drying, under the conditions used here, was determined by axis size and possibly the nature of the axis outer coverings, rather than the water activity difference between the tissue and surrounding air.     

合肥市不同生态功能区空气负离子浓度分布特征及其与气象因子的关系

空气负离子浓度与空气环境质量密切相关.以合肥市为研究对象,按照4个生态功能区(公园游览区、生活居住区、商业交通繁华区和工业区),同步进行了空气负离子浓度、主要气象要素(光照强度、气温、空气相对湿度等)观测.不同功能区空气负离子浓度的日变化特点是: 公园游览区和生活居住区日变化呈单峰形式,工业区呈双峰形式,而商业交通繁华区则比较复杂;极值出现的时间也有差异;4个功能区空气负离子浓度日变化的波动性从大到小依次为商业交通繁华区＞工业区＞生活居住区＞公园游览区.4个功能区空气负离子浓度年变化趋势基本一致,夏季最高,冬季最低.公园游览区、生活居住区、商业交通繁华区和工业区空气负离子浓度年平均值分别是819、340、149和126 个·cm^-3.影响合肥市空气负离子浓度的最主要气象因子是空气相对湿度,其次是光照强度,最小为气温.空气负离子浓度与空气相对湿度呈指数递增关系.     

全缘叶绿绒蒿的花内热量来源和温度调节功能

为探究全缘叶绿绒蒿( Meconopsis integrifolia )的花内热量来源和温度调节功能,该研究选择在全缘叶绿绒蒿的巴朗山居群,对其进行遮阴及去瓣处理,并采用红外热像仪监测全缘叶绿绒蒿的花内微环境温度日变化及花器官温度,用环境温度计监测环境温度。结果表明:(1)太阳照射显著提高全缘叶绿绒蒿花内微环境温度和花器官温度,全缘叶绿绒蒿的热量主要来源于太阳辐射。花内微环境昼夜温差显著低于环境昼夜温差,全缘叶绿绒蒿的花具有温度调节功能。(2)白天环境温度较高时,太阳照射显著提高全缘叶绿绒蒿花内微环境温度,花瓣会降低花内微环境温度; 夜间环境温度较低时,花瓣闭合会提高花内微环境温度; 花瓣闭合运动降低了花内微环境昼夜温差,产生了保温效果。(3)在太阳照射下,花器官温度差异显著,雌雄蕊温度显著高于花瓣温度,且花器官温度由雌蕊柱头中心点向外递减,全缘叶绿绒蒿能有效调控花器官各部位的温度。综上认为,全缘叶绿绒蒿的花内热量来源于太阳辐射,主要通过花瓣闭合运动降低花内微环境昼夜温差并能在太阳照射下调节各花器官的温度实现温度调节功能。     

长江安庆段河流湿地生态系统呼吸及其影响因子

研究湿地生态系统呼吸(Reco)对评价湿地生态系统碳汇功能具有重要的意义.采用涡度相关法对位于长江中游河流湿地的杨树人工林生态系统进行了长期的定位观测,根据2005-07-23～2007-12-15的数据对Reco进行估算,并分析Reco对主要环境因子的响应特征.结果表明:(1)Reco具有明显的季节变化,每年的最大值出现在8月份,最小值出现在1月份,Reco受空气温度、土壤温度和土壤含水量共同影响,总体上看空气温度是驱动Reco的主要因子;(2)在几种模拟生态系统呼吸的模型中,Van't Hoff方程、Arrhenius方程、Lloyd-Talor方程在统计意义上具有同等的能力,由空气温度和土壤含水量共同驱动的连乘模型对Reco的拟合效果最好;(3)使用连乘模型估算的2006年生态系统呼吸总量为1074.7 gC·m-2·a-1,2007年为1127.0 gC·m-2·a-1,与亚热带和温带的森林站点的测定值相接近.     

Squeezed exponential kinetics to describe a nonglassy downhill folding as observed in a lattice protein model

We previously studied the so-called strange kinetics in the two-dimensional lattice HP model. To further study the strange kinetics, folding processes of a 27-mer cubic lattice protein model with Gō potential were investigated by simulating how the bundle of folding trajectories, consisting of a number of independent Monte Carlo simulations, evolves as the folding reaction proceeds, covering a wide range of temperature. Three realms of folding kinetics were observed depending on temperature. Although at temperatures where folding was two-state-like, the kinetics was conventional single exponential, we found that the time course data were well represented by a squeezed (or "shrunken") exponential function, exp [-(t/tau)beta] with beta > 1, at temperatures lower than the folding temperature, where folding was fastest and of a nonglassy downhill type. The squeezed exponential kinetics was found to pertain to the subdiffusion on the nonglassy downhill free energy surface and presents a marked contrast both to the single exponential kinetics and to the stretched exponential kinetics that was observed at lower temperatures where folding was also downhill but topological frustration came into effect. The observed temperature dependence of the folding kinetics suggests that some small single-domain proteins may follow the squeezed exponential kinetics at about the room temperature.     

Impact of Temperature Variability on Cholera Incidence in Southeastern Africa, 1971–2006

Africa has a number of climate-sensitive diseases. One that remains a threat to public health is cholera. The aquatic environment temperature is the most important ecological parameter governing the survival and growth of Vibrio cholerae. Indeed, recent studies indicate that global warming might create a favorable environment for V. cholerae and increase its incidence in vulnerable areas. In light of this, a Poisson Regression Model has been used to analyze the possible association between the cholera rates in southeastern Africa and the annual variability of air temperature and sea surface temperature (SST) at regional and hemispheric scales, for the period 1971–2006. The results showed a significant exponential increase of cholera rates in humans during the study period. In addition, it was found that the annual mean air temperature and SST at the local scale, as well as anomalies at hemispheric scales, had significant impact on the cholera incidence during the study period. Despite future uncertainty, the climate variability has to be considered in predicting further cholera outbreaks in Africa. This may help to promote better, more efficient preparedness.     

Skinfolds and resting heat loss in cold air and water: temperature equivalence.

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29-33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100-250% of resting heat loss the following relationships between MSF and equivalent water-air temperatures were found (see article).     

新疆农田作物覆膜地温极值的时空变化

土壤温度的上限和下限值极大地影响农田作物的生长发育．根据对新疆农田2年度不同观测时刻、不同覆膜条件及不同作物的最高和最低地温的分析,可知2年度全生育期地温极值均发生在0cm位置．地温极值依观测时刻的不同而变动．覆膜最低温度始终高于裸地,说明覆膜对提高低温段土壤温度有明显作用．最低温度的日变化可用二次函数表达;14：00和20：00时最高地温可分别用深度的椭圆曲线和线性关系表达．不同条件下的地温极值和气温具有线性关系,其中裸地最低温度与气温的相关性高于覆膜;玉米最低温度与气温的相关性高于棉花;最高温度与气温的相关性比最低温度与气温的相关性差．     

Modeling of Bacterial Growth with Shifts in Temperature

The temperature of chilled foods is an important variable for the shelf life of a product in a production and distribution chain. To predict the number of organisms as a function of temperature and time, it is essential to model the growth as a function of temperature. The temperature is often not constant in various stages of distribution. The objective of this research was to determine the effect of shifts in temperature. The suitability and usefulness of several models to describe the growth of Lactobacillus plantarum with fluctuating temperatures was evaluated. It can be assumed that temperature shifts within the lag phase can be handled by adding relative parts of the lag time to be completed and that temperature shifts within the exponential phase result in no lag phase. With these assumptions, the kinetic behavior of temperature shift experiments was reasonably well predicted, and this hypothesis was accepted statistically in 73% of the cases. Only shifts of temperature around the minimum temperature for growth showed very large deviations from the model prediction. The best results were obtained with the assumption that a temperature shift (within the lag phase as well as within the exponential phase) results in an additional lag phase. This hypothesis was accepted statistically in 93% of the cases. The length of the additional lag phase is one-fourth of the lag time normally found at the temperature after the shift.     

Rate of food evacuation in roach (Rutilus rutilus) in relation to temperature, and the application of evacuation rate estimates for studies on the rate of food consumption

SUMMARY. Food evacuation in roach (total body length, range 75–150 mm) was studied at temperatures between 4.2 and 24.0 °C. The rate of food evacuation was described by an exponential function and was similar for two different food items ( Daphnia and Chaoborus ). The relation between the instantaneous rate of food evacuation ( R ) and temperature was also described by an exponential function. A model developed for estimating food consumption rates in fish was tested in a simulation experiment and there was good agreement between estimated and actual values for food consumption.     

Ammonia Flux between Oilseed Rape Plants and the Atmosphere in Response to Changes in Leaf Temperature,Light Intensity,and Air Humidity (Interactions with Leaf Conductance and Apoplastic NH4+ and H+ Concentrations)

NH3 exchange between oilseed rape (Brassica napus) plants and the atmosphere was examined at realistic ambient NH3 levels under controlled environmental conditions. Different leaf conductances to NH3 diffusion were obtained by changing leaf temperature (10 to 40[deg]C), light intensity (0 to 600 [mu]mol m-2 s-1), and air humidity (20 to 80%), respectively. NH3 adsorption to the cuticle with subsequent NH3 transport through the epidermis had no significant effect on the uptake of atmospheric NH3, even at 80% relative air humidity. NH3 fluxes increased linearly with leaf conductance when light intensities were increased from 0 to 600 [mu]mol m-2 s-1. Increasing leaf temperatures from 10 to 35[deg]C caused an exponential increase in NH3 emission from plants exposed to low ambient NH3 concentrations, indicating that leaf conductance was not the only factor responding to the temperature increase. The exponential relationship between NH3 emission and temperature was closely matched by the temperature dependence of the mole fraction of gaseous NH3 above the leaf apoplast (NH3 compensation point), as calculated on the basis of NH4+ and H+ concentrations in the leaf apoplast at the different leaf temperatures. NH3 fumigation experiments showed that an increase in leaf temperature may cause a plant to switch from being a strong sink for atmospheric NH3 to being a significant NH3 source. In addition to leaf temperature, the size of the NH3 compensation point depended on plant N status and was related to plant ontogeny.     

THE RESPONSE OF GROWTH AND BIOCHEMICAL COMPOSITION TO VARIATIONS IN DAYLENGTH, TEMPERATURE, AND IRRADIANCE IN THE MARINE DIATOM THALASSIOSIRA PSEUDONANA (BACILLARIOPHYCEAE)

The relationships between the growth rate of the marine diatom Thalassiosira pseudonana (Hustedt) and irradiance, daylength, and temperature were determined in nutrient-sufficient semicontinuous cultures. The initial slopes of the growth versus total daily irradiance curves were not affected by temperature or daylength. Growth versus irradiance was best modeled as a hyperbolic function at short daylengths and better modeled as an exponential function at longer daylengths. The maximum or light-saturated growth rates at each daylength were modeled as a hyperbolic function of daylength. This model was extended in a novel manner to include temperature dependence providing a framework that can be used to interpret other experimental data on growth rate versus daylength. The resulting model should be useful in global models of phytoplankton growth. Carbon, nitrogen, and chl a quotas were influenced by daylength, irradiance, and temperature. Both C and N quotas were positive exponential functions of irradiance, whereas N and chl a quotas were significantly greater for cells grown at the lower temperature. The ratio chl a :C quota (chl a :Q_c) was a strong negative exponential function of total daily irradiance. Cells grown at 10° C had significantly greater chl a :Q_c ratios than those grown at 18° C, and daylength also had a significant positive influence on chl a :Q_c. The apparent effect of daylength on chl a :Q_c was removed by standardizing chl a :Q_c to growth rate (μ), resulting in a temperature-dependent relationship between chl a :Q_c·μ⁻¹ and irradiance that accounted for 95% of the variation in the data.