籼稻颖花分化与退化对不同播期温光的响应

试验以三系杂交籼稻‘五优308’和‘天优华占’以及常规籼稻‘黄华占’为材料,在大田条件下,设置10个播期,研究田间不同温光条件对籼稻生育期天数、颖花分化和退化数的影响.结果表明: 温度对3个籼稻品种生育期的影响比日照长度大,平均温度升高1 ℃,播种-穗分化始期天数平均减少1.5 d,而穗分化历期天数与光照和温度的关系均不密切.不同播期间每穗颖花数和颖花分化数存在显著差异.穗分化期间平均温度、最高温度和最低温度升高,有效积温增加,昼夜温差扩大,光辐射增强,有利于穗分化期干物质积累和颖花分化,各品种趋势一致.穗分化期间有效积温增加50 ℃,颖花分化数增加10.5朵,昼夜温差扩大1 ℃,颖花分化增加14.3朵,总光辐射量增加50 MJ·m^-2,颖花分化数增加17.1朵.颖花退化率与温度呈现二次项相关,极端高温或极端低温的自然条件不利于颖花形成,但低温天气对颖花退化的影响大于高温.温度低于临界温度,颖花退化率大幅增加,穗分化期临界积温为550～600 ℃,日平均温度为24.0～26.0 ℃,日最高温度为32.0～34.0 ℃,日最低温度为21.0～23.0 ℃.适宜高温、昼夜温差大、光照辐射强的自然条件利于颖花分化,并减少颖花退化.     

芸苔链格孢菌丝生长温度的研究

通过对芸苔链格孢[Alternaria brassicae(Berk.)Sacc.]17个单孢系菌丝在PDA培养基上生长温度的研究,结果表明各菌系在相同的温度下,菌丝生长的速度存在着明显的差异。经新复极差分析,其速度可分为三个等级。其间最高与最低可相差4.7倍。对该菌菌丝最适生长温度的研究表明,17个菌系的平均最适温度为25℃。但各菌株间有着明显的差异。作者根据其最适温度的高低及其对温度的敏感性,将这17个单孢系划分为6个温度型。即:不敏感低温型、敏感亚低温型、不敏感亚低温型、敏感中温型、不敏感中温型及不敏感亚高温型等。病菌温度型的划分可作为使用该类病菌进行抗病筛选时确定最适温度的参考。     

The necessity for low temperature treatment on the eggs of Emma Cricket,Teleogryllus emma and the method of increasing the hatching rate after low temperature treatment

The necessity for low temperature treatment of Emma Cricket Eggs, Teleogryllus emma, to dormancy breaking and the method of increasing hatching rate after low temperature treatment were investigated. Emma Cricket Eggs were treated by constant temperature, room temperature, low temperature, step‐down low temperature. As a result, constant temperature treatment was the lowest on hatching rate. The hatching rates of the rest of other temperature treatments were not different statistically (one‐way ANOVA). In other word, low temperature treatment was not necessary to dormancy breaking. But low temperature treatment was necessary to control individual number of Emma Cricket, Teleogryllus emma, on the mass indoor‐rearing system. And the step‐up temperature treatment was necessary to increase hatching rate after low temperature treatment.     

Effect of temperature on the escape of charged polymer chain from a repulsive nanopore

The effect of temperature on the escape of a charged polymer chain from a repulsive nanopore is studied by Langevin dynamics simulations. The conformation properties of the charged polymer chain are dependent on the temperature as it is in random coil state at high temperature and in compact globule state at low temperature. The scaling behaviour between the escape time and polymer length is independent of temperature, while the escape time decreases with increasing the temperature in an exponential way. Different temperature-dependent behaviours are observed for the escape time in three temperature regimes: low temperature where the polymer is in compact globule state, intermediate temperature around the coil-to-globule transition temperature, and high temperature where the polymer is in the random coil state. We further find that, with a decrease in the temperature, the total number of moving steps for the escape increases sharply in the low-temperature regime while the time duration for each moving step increases sharply in the intermediate temperature regime.     

A test of biochemical symmorphosis in a heterothermic tissue: bluefin tuna white muscle

Selective brain cooling (SBC) is defined as a brain temperature cooler than the temperature of arterial blood from the trunk. Surrogate measures of arterial blood temperature have been used in many published studies on SBC. The use of a surrogate for arterial blood temperature has the potential to confound proper identification of SBC. We have measured brain, carotid blood, and rectal temperatures in conscious sheep exposed to 40, 22, and 5 degrees C. Rectal temperature was consistently higher than arterial blood temperature. Brain temperature was consistently cooler than rectal temperature during all exposures. Brain temperature only fell below carotid blood temperature during the final few hours of 40 degrees C exposure and not at all during the 5 degrees C exposure. Consequently, using rectal temperature as a surrogate for arterial blood temperature does not provide a reliable indication of the status of the SBC effector. We also show that rapid suppression of SBC can result if the animals are disturbed.     

Selecting temperature for protein crystallization screens using the temperature dependence of the second virial coefficient

Protein crystals usually grow at a preferable temperature which is however not known for a new protein. This paper reports a new approach for determination of favorable crystallization temperature, which can be adopted to facilitate the crystallization screening process. By taking advantage of the correlation between the temperature dependence of the second virial coefficient (B(22)) and the solubility of protein, we measured the temperature dependence of B(22) to predict the temperature dependence of the solubility. Using information about solubility versus temperature, a preferred crystallization temperature can be proposed. If B(22) is a positive function of the temperature, a lower crystallization temperature is recommended; if B(22) shows opposite behavior with respect to the temperature, a higher crystallization temperature is preferred. Otherwise, any temperature in the tested range can be used.     

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。     

Growth of Rhizobium japonicum Strains at Temperatures Above 27 degrees C

A study was conducted to examine the growth responses of different Rhizobium japonicum strains to increasing temperatures, determine the degree of variability among strains in those responses, and identify temperature-related growth characteristics that could be used to select temperature-tolerant strains. Each of 42 strains was grown in liquid culture for 96 h at 19 incubation temperatures ranging from 27.4 to 54.1 degrees C in a temperature gradient apparatus. Growth was estimated by measuring the change in optical density over time. Strains differed in their responses to increasing temperatures. Three characteristic temperatures were determined for each strain: the temperature giving the maximum optical density at 96 h (optimum temperature), the maximum temperature allowing a continuous increase in optical density during the 96-h period (maximum permissive temperature), and the maximum temperature allowing growth of the cultures after they were transferred to a uniform incubation temperature of 28 degrees C (maximum survival temperature). The three characteristic temperatures varied among strains and had the following ranges: optimum temperature, from 27.4 to 35.2 degrees C; maximum permissive temperature, from 29.8 to 38.0 degrees C; and maximum survival temperature, from 33.7 to 48.7 degrees C. Significant positive correlations were found between maximum permissive temperature and optimum temperature and between maximum permissive temperature and maximum survival temperature. Eight strains which had the highest maximum permissive temperature, optimum temperature, and maximum survival temperature were considered tolerant of high temperatures and were able to grow at temperatures higher than those previously reported for the most tolerant R. japonicum strains. The strains were of diverse geographical origin, but the response to high temperatures was not related to their origin. Evaluation of the temperature responses in pure culture may be useful in the search for R. japonicum strains better suited to environments in which high soil temperature is a limiting factor.     

Temperature-Sensitive Behavior of Paramecium caudatum

SYNOPSIS. The effect of temperature on the behavior of swimming cells of Paramecium caudatum has been investigated by photographic analyses of their tracks in uniform temperature, in temperature gradient, or in temperature changing with time. When the cells were placed in the temperature gradient, the frequency of discontinuous directional changes of cells swimming toward the optimal temperature, the temperature of the culture, was much lower than that of the cells swimming in the opposite direction. This difference in the frequency of directional changes explained the observed accumulation of the cells at - the optimal temperature. When the temperature was suddenly changed toward the optimum, a transient decrease of the frequency of directional changes was observed and when the temperature was changed in the reverse direction, a transient increase of the frequency was noted. This transient response to the temperature change was the origin of the dependence of the frequency of directional changes on the swimming direction in the temperature gradient. Finally, the relation between the magnitude of the transient response and the rate of the temperature change was derived.     

Esophageal and tympanic temperature responses to core blood temperature changes during hyperthermia

Esophageal, rectal, tympanic, and central blood temperature, i.e., pulmonary artery and aortic arch, were recorded in three patients during iatrogenic whole-body hyperthermia for the treatment of advanced malignant metastatic cancer. Aortic temperature closely followed changes in pulmonary arterial temperature, with an average delay time of 27 s. Esophageal temperature reflected quantitatively and more quickly (avg lag time, 80 s) the temperature changes in the pulmonary artery than tympanic membrane temperature. Tympanic temperature was consistently lower than the blood temperature of the heart during steady state. Therefore it is suggested that esophageal temperature is a preferable index of central blood temperature. Additionally, measurement of esophageal temperature can be made more easily and safely than tympanic membrane temperature.     

The regulation of isoprene emission responses to rapid leaf temperature fluctuations

Isoprene emission from leaves is temperature dependent and may protect leaves from damage at high temperatures. We measured the temperature of white oak ( Quercus alba L.) leaves at the top of the canopy. The largest short-term changes in leaf temperature were associated with changes in solar radiation. During these episodes, leaf temperature changed with a 1 min time constant, a measure of the rate of temperature change. We imposed rapid temperature fluctuations on leaves to study the effect of temperature change rate on isoprene emission. Leaf temperature changed with a 16 s time constant; isoprene responded more slowly with a 37 s time constant. This time constant was slow enough to cause a lag in isoprene emission when leaf temperature fluctuated rapidly but isoprene emission changed quickly enough to follow the large temperature changes observed in the oak canopy. This is consistent with the theory that isoprene functions to protect leaves from short periods of high temperature. Time constant analysis also revealed that there are two processes that cause isoprene emission to increase with leaf temperature. The fastest process likely reflects the influence of temperature on reaction kinetics, while the slower process may reflect the activation of an enzyme.     

A study of human skin and surface temperatures in stable and unstable thermal environments

Skin temperature is a common physiological parameter that reflects human thermal responses. The purpose of this research was to investigate the effects of radiant temperature on human skin temperature and surface temperature in stable and unstable thermal environments. For a clothed human body, the skin temperature is the surface temperature of the skin, while the surface temperature is the outer surface temperature of the clothes. For this aim, the radiant temperature from 26 to 38 °C and then from 38 to 26 °C was controlled in three different ways; in stable condition keeping stable above 40 min, in unstable condition at a rate of 2 °C/5 min, and in another unstable condition at a rate of 2 °C/10 min. Experimental data showed that at the same radiant temperature, the local skin/surface temperatures during the radiant temperature decrease were higher compared to those during the radiant temperature increase. During the radiant temperature increase/decrease, the increments/decrements of the mean skin temperature and the mean surface temperature decreased gradually from the stable condition, 2 °C/10 min to 2 °C/5 min. Compared to surface temperature, the faster the radiant temperature changed, the more obviously the change in skin temperature was delayed. These data demonstrated that the human body has physiological adaptability to unstable thermal environments.     

Responses of Paramecium to Temperature Change

SYNOPSIS. The effect of temperature on the swimming velocity of Paramecium was investigated. When paramecia cultured at 25 C were transferred to various temperatures, their swimming velocity was increased immediately and then decreased exponentially with time to a new steady velocity. The relaxation time was about 1 min, independent of the new temperature. At a constant temperature the steady velocity was inversely proportional to viscosity. The velocity acceleration was observed when the sudden temperature change was larger than ± 1 C. Its magnitude became constant when the temperature change was greater than several degrees. The steady velocity as a function of temperature had a sharp maximum at the culture temperature and decreased on both sides of this temperature. Incubation of paramecia at 30 C for several hr after cultivation at 25 C shifted the maximum temperature of the steady velocity to 30 C. The temperature at which paramecia gathered in a temperature gradient cell correlated closely with the temperature of the maximum steady velocity.     

No dynamic effector responses to fast changes of core temperature at constant skin temperature

Experiments in conscious goats were done to see whether heat production and respiratory evaporative heat loss show dynamic responses to changing core temperature at constant skin temperature. Core temperature was altered by external heat exchangers acting on blood temperature, while skin temperature was maintained constant by immersing the animals up to the neck in a rapidly circulating water bath. Core temperature was altered at various rates up to 0.9 degrees C/min. Step deviations of core temperature from control values were always followed by a positive time derivative of effector response, but never by a negative time derivative during sustained displacement of core temperature. Ramp experiments showed that the slopes at which heat production or heat loss rose with core temperature deviating from its control level grew smaller at higher rates of change of core temperature. It is concluded that neither heat production nor respiratory evaporative heat loss respond to the rate of change of core temperature. At constant skin temperature, thermoregulatory effector responses appear to be proportional to the degree to which core temperature deviates from its set level.     

黄土高原极端气温变化特征及其与平均气温的相关性

近几十年来,黄土高原极端气候频发,研究和预测极端气候的发生显得尤为重要。目前,关于极端气候的研究多关注事件本身的变化特征,而忽略了平均气温与其变化趋势的相关分析。本研究基于1986—2019年黄土高原79个气象站的逐日最高气温、最低气温和平均气温资料,采用线性倾向估计、Mann-Kendall检验、滑动t检验以及Pearson相关分析方法,对黄土高原地区极端气温的变化趋势及其与平均气温的相关性进行研究。结果表明: 研究期间,黄土高原地区极端气温暖指数呈显著上升趋势,冷指数呈显著下降趋势,极端高温事件发生频率增加;大多极端气温指数在20世纪90年代中后期和2012年发生突变,且极端气温在1998—2012年整体呈现下降趋势,较好地响应了全球变暖停滞现象;平均气温在西部黄土高塬沟壑区、土石山区及河谷平原区的上升趋势较其他区域明显,且极端气温指数大幅变化趋势的站点几乎都发生在平均气温大幅上升的区域;平均气温的小幅上升显著增加了极端高温事件发生的频率,其中,极端低温的变化幅度和速率大于极端高温,气候变暖对极端气温指数产生了不同影响,平均气温的微小变化使得黄土高原整体气候分布向着更易发生热浪的方向转移。     

低温和光周期对绿盲蝽越冬卵滞育解除和发育历期的影响

为了探讨温度和光周期对绿盲蝽Apolygus lucorum Meyer-Dür越冬卵滞育解除和发育历期的影响, 系统调查了绿盲蝽越冬卵在不同温度和不同光照组合下的孵化率和孵化时间, 结果显示：绿盲蝽的越冬卵均为滞育卵,低温和光周期对绿盲蝽越冬卵的滞育解除均有影响。2℃的低温处理能够显著促进其滞育解除,在0~65 d范围内,随着低温处理时间增长,其滞育解除时间缩短,未经低温处理的越冬卵T₅₀为68.5 d,低温处理65 d的T₅₀为12.25 d,绿盲蝽越冬卵在2℃低温处理65 d后完全解除滞育;在0~40 d范围内,低温处理时间越长,绿盲蝽越冬卵的孵化率越高,在25℃、全光照的条件下不经低温处理的孵化率为68.65%,低温处理40 d后在25℃的条件下的孵化率达到99.46%。在20~26℃范围内,绿盲蝽越冬卵的滞育后发育历期随着温度的上升而缩短, 随着光周期的延长而缩短。结果说明低温处理能够提高绿盲蝽越冬卵滞育解除率,但不是其滞育解除的必要条件,低温处理与自然变温对绿盲蝽滞育解除的作用相似;高温和长光照能够促进绿盲蝽的滞育解除,缩短发育历期。     

黑龙江省水稻品种跨积温区种植的产量和品质变化

采用在不同积温区布置田间试验的方法,比较研究了黑龙江省5个水稻主栽品种产量和品质随积温的变化.结果表明： 水稻产量随积温呈二次曲线变化,其相关程度因水稻品种而异;水稻穗数、穗粒数与积温呈极显著二次曲线关系,而千粒重与积温之间相关关系不显著;水稻籽实空瘪率从适宜积温区到低积温区显著增加,而从适宜积温区到高积温区变化不明显;水稻垩白率、整精米率与积温均呈极显著二次曲线关系,即垩白率和整精米率在适宜积温区分别有最小值和最大值存在;稻米蛋白质、直链淀粉含量和食味随积温变化不明显.根据对温度敏感程度的不同,可将水稻品种划分为温敏型、中间型、温钝型3类,其适宜栽培积温带宽度和允许栽培积温带宽度分别为300 ℃和420 ℃、360 ℃和440 ℃、380 ℃和520 ℃.根据积温因地制宜地选种水稻品种对于提高水稻产量、改善稻米品质十分重要.     

Scrotal heating stimulates panting and reduces body temperature similarly in febrile and non-febrile rams (Ovis aries)

It is known that heating the ram scrotum stimulates heat loss resulting in a decrease in body temperature and that during fever core temperature increases, but local scrotal thermoeffectors operate to maintain normal scrotal temperature. We have investigated whether scrotal warming influences core body temperature and the panting effector during fever generation. We measured rectal temperature, intrascrotal temperature, scrotal skin temperature and respiratory frequency in four adult Merino rams following intravascular injection of saline or lipopolysaccharide at an ambient temperature of 18-20 degrees C while scrotal skin temperature was maintained at 33 degrees C or elevated to 41 degrees C. Compared to maintaining normal scrotal temperature, heating the scrotum increased respiratory frequency and reduced rectal temperature by a similar amount following LPS as following saline. Fever was associated with decreased respiratory frequency compared to saline at both 33 and 41 degrees C scrotal temperature, suggesting that the fever was generated mainly by decreasing respiratory heat loss. We conclude that scrotal thermal afferent stimulation resulted in an offset for the set-point of body temperature regulation in both normothermic and febrile rams.     

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．     

Growth of Rhizobium japonicum Strains at Temperatures Above 27°C

A study was conducted to examine the growth responses of different Rhizobium japonicum strains to increasing temperatures, determine the degree of variability among strains in those responses, and identify temperature-related growth characteristics that could be used to select temperature-tolerant strains. Each of 42 strains was grown in liquid culture for 96 h at 19 incubation temperatures ranging from 27.4 to 54.1°C in a temperature gradient apparatus. Growth was estimated by measuring the change in optical density over time. Strains differed in their responses to increasing temperatures. Three characteristic temperatures were determined for each strain: the temperature giving the maximum optical density at 96 h (optimum temperature), the maximum temperature allowing a continuous increase in optical density during the 96-h period (maximum permissive temperature), and the maximum temperature allowing growth of the cultures after they were transferred to a uniform incubation temperature of 28°C (maximum survival temperature). The three characteristic temperatures varied among strains and had the following ranges: optimum temperature, from 27.4 to 35.2°C; maximum permissive temperature, from 29.8 to 38.0°C; and maximum survival temperature, from 33.7 to 48.7°C. Significant positive correlations were found between maximum permissive temperature and optimum temperature and between maximum permissive temperature and maximum survival temperature. Eight strains which had the highest maximum permissive temperature, optimum temperature, and maximum survival temperature were considered tolerant of high temperatures and were able to grow at temperatures higher than those previously reported for the most tolerant R. japonicum strains. The strains were of diverse geographical origin, but the response to high temperatures was not related to their origin. Evaluation of the temperature responses in pure culture may be useful in the search for R. japonicum strains better suited to environments in which high soil temperature is a limiting factor.