冬季小麦叶片光合作用对温度响应方式的变化

冬季田间生长的小麦离体叶片净光合速率（Ｐｎ）对温度的响应有两种方式。在１２月上旬可以观测到第一种方式。在离体叶片周围空气温度从１０℃逐步升到３０℃后的１ｈ内Ｐｂ逐渐升高,在随后气温逐步降低到１０℃的过程中,Ｐｎ都比先前升温过程中同样温度下的数值高。３０℃下叶片胞间ＣＯ２浓度（Ｃｉ）降低和叶片无机磷含量增高表明,这种响就态度苛能起因于一些光合碳同化酶活性的增高。在１２月中旬以后可以观测到第二种方式。     

温州蜜柑叶片气体交换和叶绿素荧光对低温的响应

研究了低温对温州蜜柑叶片气体交换和叶绿素荧光的影响,结果表明：（１）８℃低温处理１１８ｈ对气体交换和叶绿纱荧光影响不大。（２）２℃低温处理１５ｈ后,净光合速率（Ｐｎ）、气孔导度（Ｇｓ）,羧化效应（ＣＥ）下降,胞间ＣＯ２浓度（Ｃｉ）升高,表观量子效率（ＡＱＹ）和叶绿素荧光参数ＦＱ及Ｖｖ／Ｆｍ没有显著变化。（３）室外自然低温处理作７ｄ,Ｐｎ、Ｇｓ、ＣＥ饱和ＣＯ２光合速率、ＡＱＹ及Ｆｖ／Ｆｍ显著下降,Ｃ     

田间在豆叶片光合作用与活性氧清除酶的日变化

开花期大豆叶片光合速率（Ｐｎ）在晴天中午伴随气孔导度（Ｇｓ）下降而降低,而叶温（ＴＬ）、光呼吸速率（Ｐｒ）以及Ｐｒ／Ｐｎ比值在中等前后明显上升。胞间ＣＯ２浓度（Ｃｉ）在上午下降,之后则逐渐增加。在最高光量子密度（ＰＦＤ）低于１．２ｍｍｏｌ·ｍ＾－２·ｓ＾－１的多云天气,大豆叶片Ｐｎ与Ｐｒ的日变化依赖于ＰＦＤ、Ｃｉ与ＰｒＰｎ比值在一天中基本恒定。晴天与多云天气大豆叶片细胞活性氧清除系统的超氧物歧化酶     

水稻光合速率、气孔导度和Rubisco活力的日变化

在晴天有时有云天,水稻剑叶的最大光合速率出现在午前９：００左右。中午前后,无论光合量子通量（ＰＰＦ）等于或略低于９：００前后,净光合率（Ｐｎ）及Ｐｎ／ＰＰＦ比值均较低。ＲＯｂｉ８ＣＯ＆化活力有明显的日变化,无论以单位面积计算或以该酶蛋白为基数计算,其总活力和初始活力均呈日出前最低,中午最高,傍晚又下降的单峰曲线。中午Ｐｎ下降期间,Ｐｎ与Ｃｉ有极显著正相关,与ＲＯｂｉｓＣＯ初始活力无相关;而早晚,瞬时人工光照下Ｐｎ与Ｒｕｉｓｃｏ初始活力呈直线正相关,与Ｃｉ呈直线负相关。这表明中午光合下降来自气孔限制,而晚低光合主要由低Ｒｕｂｉｓｃｏ初始活力所致。     

午间强光胁迫下SOD对大豆叶片光合机构的保护作用

晴天田间大豆叶片Ｐｎ与Ｐｒ均表现出明显的日变化,Ｐｎ日变化曲线里双峰型,中午前后降低。Ｐｒ随日照强度的增加而增加,至上午１１时左右达最大值,然后缓慢下降。普通空气及低氧空气中的ＡＱＹ均在中午前后降低。ＳＯＤ活性也有明显的日变化,最高值出现在下午１６时左右。强光下喷施ＳＯＤ抑制剂ＤＤＴＣ明显降低Ｐｎ及低氧空气中的ＡＱＹ;而在低于叶片光合作用饱和光强下喷施同样浓度ＤＤＴＣ则对Ｐｎ及低氧空气中的ＡＱＹ无明显影响。中午前后ＳＯＤ活性及Ｐｒ的增加对于保护光合机构免受强光的破坏具有重要意义。     

辣椒疫霉致病毒素

辣椒疫霉在培养液中振荡培养时可分泌毒素,这种纱能经志辣椒叶片形成水渍状褐腐斑,类似病原菌侵染后形成的症状,Ｐｌｉｃｈ’ｓ和Ｖ８Ｃ２液适于Ｐ．ｃａｐｓｉｃｉ的生长和产毒;生长适宜温度和ＰＨ范围分别为２０－３０℃和ＰＨ６－７,在２５－３０℃、Ｐ５－８的条件下２滤液毒性最强;培养１５天产毒达到最高值,液先后经８５％硫酸铵沉淀,ＤＥ５２、Ｃ几ＳｅｐｈａｄｅｘＧ－７５柱层将毒素纯化。经鉴定该纯毒素为３９．８     

变温过程中大鼠心肌等长收缩发展张力呈双相变化

本实验旨在探明变温过程对心肌的影响,以及可能的内在机理。采用阶梯方式降、复温,测定３０℃、２５℃、２０℃、１５℃与１０℃条件下,大鼠乳头肌等长收缩的各参数值的变化。结果表明：在降温过程中,心肌发展张力（ＤＴ）呈双相变化,即从３０℃降温到２５℃,ＤＴ增大,而后ＤＴ逐渐下降;温度降到２０℃时,静息张力（ＲＴ）保持不变,而降至１５℃以后ＲＴ明显上升。乳头肌等长收缩的时间参数如ＴＰＰ、ＴＰＮ、ＴＰＴ、Ｔ１／２Ｒ均随温度的降低而逐渐延长。在复温过程中,与降温过程中相同温度点相比,２０℃、２５℃、３０℃点发展张力明显降低,而１５℃、２０℃、２５℃点静息张力显著增高。这提示在降温过程中,心肌细胞肌钙蛋白Ｃ对Ｃａ２＋敏感性可能呈现双相变化,且低温造成的心肌细胞内游离Ｃａ２＋浓度增高,可能引起心肌细胞损伤。因而,心冷停搏液保护心肌功能的关键环节,应是如何防止在降温过程中心肌细胞内游离Ｃａ２＋浓度一过性增高。     

不同温湿度组合对安微虫瘟霉诱发桃蚜病害的影响

用孢子浴方法,对４２批次桃蚜Ｍｙｚｕｓ ｐｅｒｓｉｃａｅ（３０－６０头／批）接种大剂量（孢子７９－９０个／ｍｍ＾２）安徽虫瘟霉Ｚｏｏｐｈｔｈｏｒａ ａｍｈｕｉｅｎｓｉｓ的分生孢子,在２０℃下保湿２４ｈ后转入不同温度（１０℃、１５℃、２０℃、２５℃、３０℃及自然变温下１．５－１６．６℃和８．５－２０．２℃）和温度（５０％、６５％、８０％、９０％９５％及１００％ＲＨ）的组合条件下观察桃蚜的反应。结果表     

不同环境条件下沙生植物的CO2气体交换研究

对腾格里沙坡头地区两种沙生植物：油蒿（ＡｒｔｅｍｉｓｉｓａｏｒｄｏｓｉｃａＫｒａｓｃｈ．）和柠条（ＣａｒａｇａｎａｋｏｒｓｈｉｎｓｋｉｉＫｏｍ）。在旱季和雨季时ＣＯ２气体交换特点及其动态变化进行了研究,结果表明：在干旱条件下,油蒿（Ａ）和柠条（Ｃ）的光合作用均受到严重影响,其光合率率日变化日出后（７：００－９：ａ．ｍ．）有一较小高峰外,基本处于很低水平。降水后,Ａ和Ｃ的光合作用均明显提高,但Ｐｎ     

光合作用对光和二氧化碳响应的观测方法探讨

用便携式光合仪LI-6400观测自然条件下生长的盆栽蚕豆叶片光合作用对光和二氧化碳的响应发现：（1）用未经过光合诱导的叶片观测光合作用对光的响应会得到即使在全太阳光强下光合作用仍然不饱和的假象;（2）利用某些经验方程计算的饱和光强远低于实际观测值;（3）在观测光合作用对CO2的响应过程中,每一次CO2浓度变化都应当伴随一次光合仪的匹配步骤,否则所得结果偏差很大;（4）在不饱和光下观测光合作用对CO2的响应,会导致对叶片光合能力的低估。     

The effects of inbreeding and heat stress on male sterility in Drosophila melanogaster

Understanding the consequences of inbreeding in combination with stress is important for the persistence of small endangered populations in a changing environment. Inbreeding and stress can influence the population at all stages of the life cycle, and in the last two decades a number of studies have demonstrated inbreeding depression for most life‐cycle components, both in laboratory populations and in the wild. Although male fertility is known to be sensitive to temperature extremes, few studies have focused on this life‐cycle component. We studied the effects of inbreeding on male sterility in benign and stressful environments using Drosophila melanogaster as a model organism. Male sterility was compared in 21 inbred lines and five non‐inbred control lines at 25.0 and 29.0 °C. The effect of inbreeding on sterility was significant only at 29.0 °C. This stress‐induced increase in sterility indicates an interaction between the effects of inbreeding and high‐temperature stress on male sterility. In addition, the stress‐induced temporary and permanent sterility showed significant positive correlation, as did stress‐induced sterility and the decrease in egg‐to‐adult viability. This suggests that the observed stress‐induced decline in fitness could result from conditionally expressed, recessive deleterious alleles affecting both sterility and viability simultaneously. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 432–442.     

Response of moist-air receptor on antenna of the stick insect,Carausius morosus,to step changes in temperature

Summary The moist-air sensory cell in the antennal mound-shaped sensillum of Carausius responds to changes in relative humidity brought about by changing either the temperature (T) of the air or the partial pressure of water vapor (Pw) (Figs. 1, 5). When changes in either parameter cause relative humidity (Hr) to rise between roughly 5% and 55%, the same Hr-changes elicit very close to the same responses, no matter how Hr is changed (Figs. 2, 3). Even the resolving power for upward Hr-steps produced by lowering T is very close to that produced by raising Pw: 7.4% vs. 6.3%. Thus upward transients in impulse frequency (F) may be read off directly as quantitative rises in Hr. Whether the rise in Hr as signalled by the moist-air cell is the result of a rise in Pw or of a drop in T could well be indicated by the simultaneous reactions of the cold and dry-air cells (Figs. 1, 5). The moist-air cell also reacts to downward step changes in Hr, but very differently, depending on how they are brought about. Upward steps in T have a much larger effect on F than corresponding downward steps in Pw (Fig. 4). This result demonstrates that changes in relative humidity do not suffice to explain the changes in the activity of the moist-air cell. The receptor may be better construed as bimodal, reacting to changes in T and Pw with independent sensitivities and well matched to relative humidity when changes in either lead to increases in this parameter. The moistair cell's responses to T-steps at Pw = 0 (Figs. 1, 5) offer some support for this interpretation.Abbreviations F impulse frequency in impulses/s (imp/s) - Hr relative humidity in % - Ps saturation pressure of water vapor in torr - Pw partial pressure of water vapor in torr - r correlation coefficient - T temperature in °C     

The genetics of dopa decarboxylase in Drosophila melanogaster. III. Effects of a temperature sensitive dopa decarboxylase deficient mutation on female fertility

The mutation Ddc^ts1 effects female sterility when homozygous, hemizygous, or heterozygous over a series of Ddc null alleles (Ddc^x) indicating that some aspect of Ddc gene function is necessary for female fertility. Ovary transplant experiments demonstrate that the female sterility phenotype is ovary autonomous. Two to 3% of the total DDC activity measurable in newly hatched females is localized in their previtellogenic ovaries. The degree to which females heterozygous for Ddc^ts1 over different Ddc null alleles are fertile at 22°C reflects a continuous spectrum of allelic complementation similar to that observed for the effects of these genotypes on viability at 30°C. Fertility of all the Ddc^ts1/Ddc^x females tested is significantly depressed at 30 vis-a-vis 22°C providing evidence that it is the DDC enzyme activity itself which is required for female fertility. Ddc^ts1/Ddc^ts1 homozygous and Ddc^ts1/Df hemizygous females are nonconditionally, completely sterile at 18, 20, 22, 25, and 30°C. Although all homo- and hemizygous females do lay some eggs, no evidence of embryogenesis or fertilization has ever been detected. The absolute, nonconditional sterility of Ddc^ts1 homo- and hemizygous females stands in stark contrast to the conventional temperature dependent effects of these same genotypes on viability and to the temperature sensitive effects of Ddc^ts1/Ddc^x heterozygous females on both fertility and viability. Reasons for these tissue-specific and genotypic differences are discussed.     

Low temperature and defoliation affect fructan-metabolizing enzymes in different regions of the rhizophores of Vernonia herbacea

In addition to the storage function, fructans in Asteraceae from floras with seasonal growth have been associated with drought and freezing tolerance. Vernonia herbacea, native of the Brazilian Cerrado, bears underground reserve organs, rhizophores, accumulating inulin-type fructans. The rhizophore is a cauline branched system with positive geotropic growth, with the apex (distal region) presenting younger tissues; sprouting of new shoots occurs by development of buds located on the opposite end (proximal region). Plants induced to sprouting by excision of the aerial organs present increased 1-fructan exohydrolase (1-FEH) activity in the proximal region, while plants at the vegetative stage present high 1-sucrose:sucrose fructosyltransferase (1-SST) in the distal region. The aim of the present study was to analyze how low temperature (5 °C) could affect fructan-metabolizing enzymes and fructan composition in the different regions of the rhizophores of intact and excised plants. 1-SST and 1-fructan:fructan fructosyltransferase (1-FFT) were higher in the distal region decreasing towards the proximal region in intact plants at the vegetative phase, and were drastically diminished when cold and/or excision were imposed. In contrast, 1-FEH increased in the proximal region of treated plants, mainly in excised plants subjected to cold. The ratio fructo-oligo to fructo-polysaccharides was significantly higher in plants exposed to low temperature (1.17 in intact plants and 1.64 in excised plants) than in plants exposed to natural temperature conditions (0.84 in intact vegetative plants and 0.58 in excised plants), suggesting that oligosaccharides are involved in the tolerance of plants to low temperature via 1-FEH, in addition to 1-FFT. Principal component analysis indicated different response mechanisms in fructan metabolism under defoliation and low temperature, which could be interpreted as part of the strategies to undergo unfavorable environmental conditions prevailing in the Cerrado during winter.     

低温秸秆降解微生物菌剂的研究进展

秸秆的成分主要有纤维素、半纤维素和木质素等,降解秸秆的微生物包括细菌、放线菌和真菌。低温秸秆降解微生物的选育方法有直接从自然界中筛选、诱变育种、原生质体融合育种、基因工程育种等。目前,筛选获得的低温秸秆降解菌株的数量有限,降解秸秆的能力不高,低温条件下菌株的降解机理都需要进一步的研究。综述了低温条件下秸秆降解微生物菌剂的研究进展。     

次生栎林与火炬松人工林土壤呼吸的季节变异及其主要影响因子

土壤呼吸是陆地生态系统碳循环的重要组成部分.随着全球气候变暖趋势逐渐明显,土壤呼吸的时空变异及其对温度变化的响应已成为生态学研究的重要内容之一.利用LI-6400-09土壤碳通量观测仪,在江苏省南京林业大学下蜀实验基地,采用随机区组实验设计方法,连续两年测定了北亚热带次生栎林和火炬松人工林土壤呼吸的季节动态变化,结果表明:(1)两种林分内土壤呼吸速率均具有明显的季节波动,表现为:在最冷的1月份,土壤呼吸速率最低,随着土壤温度的升高,土壤呼吸速率也逐渐上升,在7、8月份达到最大值,随后又逐渐下降;(2)次生栎林月平均土壤呼吸速率在0.271～3.22μmolCO2 · m-2 · s-1之间,年变异幅度为11.88;火炬松人工林月平均土壤呼吸速率在0.336～3.06μmolCO2 · m-2 · s-1 ,年变异幅度为9.11;(3)次生栎林土壤呼吸的 Q10值在2.19至2.27之间,火炬松人工林土壤呼吸的Q10值在2.02至2.15之间,次生栎林土壤呼吸对温度的敏感性大于火炬松人工林;(4)土壤呼吸速率与不同深度层次土壤温度之间均呈显著性正相关,与土壤微生物生物量之间呈显著性负相关,而与土壤含水率、凋落物输入量之间相关不显著.研究结果初步阐明了江淮流域北亚热带典型森林植被土壤呼吸的季节动态特征及主要影响因子,为进一步揭示该区域森林土壤碳循环特点提供了理论基础.     

MTCLIM模型日平均温度调和系数获得算法的改进

MTCLIM模型对日平均温度的模拟结果是基于日平均温度调和系数（TEMCF）的值,而国内外目前对该系数的估计多直接基于简单的最小二乘法进行该系数的本地化,我国学者的相关工作多直接引用原模型在北美干旱气候条件的测定默认值,因而往往造成模拟结果误差较大。首次提出了根据不同水热条件的影响确定TEMCF值的方法,大大改善了最后模拟结果的精度。以长白山地区为例,通过对我国典型山地条件下日平均温度的推算方法的对比,对不同水热条件下MTCLIM模型日平均温度调和系数的获得算法进行了验证。结果证明不同水热条件对该模型日平均温度估算算法中TEMCF的值有较大的影响。随着降水量的增加和日照时间的缩短,TEMCF的取值呈减小趋势,这也解释了原MTCLIM模型在我国山地地区的应用研究的结果中较大时空差异性的原因。通过不同水分和热量等级下的模拟结果表明,将TEMCF值根据水热条件情况分别模拟日平均气温将能够大大改善MTCLIM模型在典型山地地区中的模拟结果,从而为山地地区的研究工作提供更准确的基础性参考资料。     

冠层温度在水稻抗旱性基因型筛选中的应用及其测定技术

本文综述了冠层温度在水稻抗旱性基因型筛选中的应用及其研究进展,并介绍了利用红外测温仪测定冠层温度的方法。作物不同基因型之间存在冠层温度的差异,并且从理论上讲,冠层温度与作物水分利用相关,因而把冠层温度作于作物基因型筛选是有价值而且是可行的。利用红外测温仪测定水稻冠层温度是一顶非接触性测温法,为水稻抗旱性基因型的筛选提供了一种简便、快速、非破坏性的技术。     

Pressure effects on thermal preference behaviour in gammarid amphipods from 600–1000m in Lake Baikal

Temperature preference behaviour of gammarid crustaceans from depths between 600–2000 m in Lake Baikal was studied in a system which provided a stable temperature gradient at pressures ranging from 50–150 atm. At the pressure of their habitat, these animals show well-defined modal distributions of sojourn temperatures around mean values from 3.0–5.5°C, av. 3.9 ± 0.3°C; mean modal T_p is estimated at 3.5°C. Year-round habitat temperatures are 3.0–3.6°C. The effect of changing pressure upon sojourn temperatures was explored over the range 50–150 atm. The slope of the mean sojourn temperature/pressure curves was 2.1°C/100 atm, significantly greater than 0. Mean nodal temperature estimates indicate that the corresponding slope in the range of 50–100 atm is 3°C/100 atm, and in the range of 100–150 atm, is likely to exceed 5°C/100 atm.     

不同水分下限对温室膜下滴灌甜瓜开花坐果期地温的影响

土壤水热状况是影响甜瓜生长及坐果的重要因素.本文以膜下滴灌为供水方式,在开花坐果期设计了重度亏缺（55%田间持水量,T₁）、中度亏缺（65%田间持水量,T₂）、轻度亏缺（75%田间持水量,T₃）和不亏缺（85%田间持水量,CK）4种水分控制下限处理,研究了不同水分控制下限对温室滴灌甜瓜耕层温度的影响,在此基础上探讨了耕层（0～20 cm）不同水热比值对甜瓜生长发育及坐果情况的影响.结果表明;甜瓜在开花坐果期间,耕层的平均地温为T₁＞T₂＞T₃＞CK,地温与土壤含水率呈反比.晴天、阴雨天及灌水后的地温日最大变幅均出现在膜内地表,最小变幅出现在膜外地表以下20 cm处;地温极值与土壤深度密切相关,地表极值与地下10和20 cm的极值差异显著.该阶段选择T₃作为灌水标准,即水热比值为1.62 mm·℃^-1时,植株的生长速率最快,坐果历时最短且坐果率最高.综合考虑温室膜下滴灌甜瓜在开花坐果期的土壤水分与地温的关系,认为T₃处理可使耕层土壤水热比值（水热比值为1.62 mm·℃^-1）达到最佳状态,更有利于甜瓜的生长发育和坐果.