灰蓝姬鹟的孵卵节律

2 0 0 2年在莲花山自然保护区使用温度自动记录装置对灰蓝姬的孵卵节律进行了研究。研究表明 ,灰蓝姬雌鸟日平均离巢 31.2 5± 7.5 0次 (n =8天 ) ,平均每次离巢持续时间为 7± 2min (n =2 6 4 ) ,平均在巢持续时间 2 1± 9min (n =2 5 6 )。雌鸟在巢率与环境温度间存在显著的负相关关系 (Spearman相关 ,r =- 0 .30 4 ,P <0 .0 1)。进一步的分析表明 ,灰蓝姬雌鸟每次离巢持续时间与环境温度呈显著的正相关 (Spearman相关 ,r =0 .2 6 1,P <0 .0 1) ,每次在巢时间和离巢次数均与环境温度无关 (在巢时间 ,r =0 .0 2 6 ,P =0 .6 82 ;离巢次数 ,r =0 .0 14 ,P =0 .879)。认为灰蓝姬雌鸟主要通过调节离巢时间的长短来控制孵卵节律     

温度对土壤氧化大气CH4的影响

讨论了温度对土壤氧化大气CH4的影响及其机理。当温度较低时土壤也具有一定的氧化大气CH4的能力,两者具有很高的相关关系,但是由于CH4氧化菌对大气CH4具有很强的亲和力以及大气CH4氧化所需活化能较低,因此土壤氧化大气CH4对温度的敏感度远低于产CH4,导致温度系数Q10较小。当大气CH4和O2扩散进入土壤的速率等于土壤中CH4和O2消耗的速率时,大气CH4氧化达到最大值,此时的土壤温度就是CH4氧化的最佳温度。如果温度继续升高并大于最佳温度,由于CH4氧化菌无法与利用O2能力更强的硝化细菌和其它微生物竞争利用土壤空气中有限的O2,使得土壤中CH4氧化菌的繁殖和活性降低。这一作用机理的提出较好地解释了为什么随着温度升高土壤氧化大气CH4能力呈低高低的态势。     

低温敏核不育水稻go543S育性对温、光的反应

以新型光温敏核不育（PTGMS,Photo-thermo sensitive genic male sterile)水稻go543S为材料,通过自然生态条件下和人工温、光处理条件下的育性观察,对其育性转换与温度和光周期的关系进行了研究。结果表明：go543S育性主要受温度控制,表现为低温条件下不育,高温条件下可育,育性转换的不育临界温度值为29．5℃,对温度传感的部位是幼穗,敏感时期为花粉母细胞形成致减数分裂,对应的剑叶叶枕距变化范围为－12．2－＋0．7cm;育性敏感期在人工恒温28．0℃条件下,无论长日（14－16h）或短日（10－12h）处理均表现不育,其不育性不受光周期影响,在人工恒温31.5℃条件下,无论长日还是短日处理均表现可育,但短日可明显提高其可育性。     

温度对谷胱甘肽分批发酵的影响及动力学模型

研究了24～32℃范围内产朊假丝酵母生产谷胱甘肽的分批发酵过程,发现较高温度对细胞生长有促进作用,而较低温度则更有利于谷胱甘肽产量的提高。应用改进的Logistic和LuedekingPiret方程分别对细胞生长动力学和谷胱甘肽合成动力学进行了模拟,得到不同温度下各种动力学参数。在此基础上,进一步研究了温度同细胞生长动力学参数之间的内在联系,得到谷胱甘肽分批发酵过程中细胞浓度的变化同温度以及底物浓度之间的一般关系式：dX-dt＝［0.0224(T+1.7)］2X(1-X/X_max)1+S｛8.26×10.6×exp［-31477/R/(T+273)］｝。验证实验结果表明,该模型具有很好的适用性。     

高温干旱下两种冷季型草坪草叶片细胞超微结构的变化

多年生黑麦草和葡匐股颖在36℃下,控水处理6d,叶片细胞的超微结构与对照相比发生明显变化,叶绿体肿胀,被膜和片层破损,部分叶绿体变圆并向细胞中央移位,这可能有利于减少对阳光的吸收;线粒体和脂质球体数量增加;葡匐翦股颖的线粒体脊解体,但黑麦草的线粒体只受轻微影响。结果说明,两种草坪草的耐热性都较弱,但多年生黑麦草的耐热性稍强于匐匐剪胶颖。     

不同地理种源西南桦苗木的耐热性研究

由于受全球气候变化的影响,近年来我国一些地区出现了异常高温天气,这越来越引起林业工作者的重视。以亚热带珍贵用材树种西南桦为研究对象,以采集于我国广西和云南两省区12个种源的西南桦种子所育苗木为实验材料,对不同种源苗木在41C高温处理下的生理指标(叶片电导率、净光合速率、蒸腾速率和根系活力)的变化进行了综合评价,来选择耐热性优良的种源。结果表明,各生理指标在高温处理后与处理前相比发生了较为明显的变化,其中,叶片电导率增高为对照温度(25C)的1．2倍,光合速率、蒸腾速率和根系活力则分别只有对照温度的60％、21％和6％;方差分析发现,在对照温度下,各生理指标在不同种源间的差别不明显,而在41C高温处理后,这种差异达到显著程度。用模糊数学的隶属度函数对参加试验的12个种源西南桦苗木的耐热性进行综合评价发现,凌云种源的耐热性最强,建议作为推荐优先发展的种源。     

The Estrogen Antagonist EM‐652 and Dehydroepiandrosterone Prevent Diet‐ and Ovariectomy‐Induced Obesity

Objective: EM‐652 is a pure antiestrogen in human breast and uterine cancer cells that also reduces bone loss and plasma lipid levels in the rat. This study aimed to assess the ability of EM‐652, alone or with dehydroepiandrosterone (DHEA), to prevent obesity and related metabolic abnormalities induced by an obesity‐promoting diet and ovariectomy. Research Methods and Procedures: Female rats were fed a high‐sucrose, high‐fat (HSHF) diet, were left intact or ovariectomized (OVX), and were treated with EM‐652, DHEA, or both for 20 days. Variables of energy balance and determinants of lipid metabolism and insulin sensitivity were assessed. Results: The HSHF diet (vs. chow) and OVX both increased energy intake and gain, as well as energetic efficiency. Both EM‐652 and DHEA prevented diet‐ and OVX‐induced energy gain mainly by decreasing fat deposition, without being additive. The modest EM‐652‐induced increase in liver triglycerides of intact rats was prevented by its combination with DHEA. EM‐652, but not DHEA, decreased cholesterolemia. The HSHF diet and OVX reduced insulin sensitivity, an effect that was attenuated by EM‐652 and abrogated by DHEA and EM‐652+DHEA. Treatment with EM‐652, DHEA, or their combination abolished the diet‐ and OVX‐induced increase in adipose lipoprotein lipase activity that accompanied fat gain. Discussion: EM‐652 is an effective agent to prevent diet‐ and OVX‐induced obesity and its associated cardiovascular risk factors such as insulin resistance. The addition of DHEA prevents hepatic lipid accumulation and further ameliorates insulin sensitivity. The beneficial metabolic effects of such combined steroid therapy may, therefore, eventually prove to be clinically relevant.     

Medium‐Chain Oil Reduces Fat Mass and Down‐regulates Expression of Adipogenic Genes in Rats

Objective: To test the hypothesis that adipose tissue could be one of the primary targets through which medium‐chain fatty acids (MCFAs) exert their metabolic influence. Research Methods and Procedures: Sprague‐Dawley rats were fed a control high‐fat diet compared with an isocaloric diet rich in medium‐chain triglycerides (MCTs). We determined the effects of MCTs on body fat mass, plasma leptin and lipid levels, acyl chain composition of adipose triglycerides and phospholipids, adipose tissue lipoprotein lipase activity, and the expression of key adipogenic genes. Tissue triglyceride content was measured in heart and gastrocnemius muscle, and whole body insulin sensitivity and glucose tolerance were also measured. The effects of MCFAs on lipoprotein lipase activity and adipogenic gene expression were also assessed in vitro using cultured adipose tissue explants or 3T3‐L1 adipocytes. Results: MCT‐fed animals had smaller fat pads, and they contained a considerable amount of MCFAs in both triglycerides and phospholipids. A number of key adipogenic genes were down‐regulated, including peroxisome proliferator activated receptor γ and CCAAT/enhancer binding protein α and their downstream metabolic target genes. We also found reduced adipose tissue lipoprotein lipase activity and improved insulin sensitivity and glucose tolerance in MCT‐fed animals. Analogous effects of MCFAs on adipogenic genes were found in cultured rat adipose tissue explants and 3T3‐L1 adipocytes. Discussion: These results suggest that direct inhibitory effects of MCFAs on adiposity may play an important role in the regulation of body fat development.     

孢粉及其他标识重建和PMIP模拟末次大冰期年均温——协调资料-模型比较法尝试

气象资料检测证明了气候模型模拟现代温度比用更复杂的湿度平衡模型好得多,而根据地质资料在山区和沿海地区重建和模型模拟的可信度要低一些,所以在比较地质资料和过去气候模拟时要考虑这个实际情况,在当前研究中我们进行末次大冰期资料一模型比较时以年均温为例,在使用所有点的资料时出现了模拟和重建之间的不一致,相反,当去掉那些模棱两可的地点后结果变得意外的好,在少数情况下结果不同时,边界条件不确定或者资料太少是模型和资料不一致的主要原因,通过使用模拟和资料的区域性平均值,我们证明了PMIP能够正确地模拟出地球陆地上区域性的年均温,在区域性研究中因经常使用未经选择的资料作为模型确认值,因而很难获得这一重要的结论。     

Influence of temperature and nutrients on species richness of deep water corals from the western coast of the Americas

Studies on biogeography of stony corals from the eastern Pacific have been conducted in detail only for reef species, and to date there have been no attempts to explain the differences of regional species richness on the basis of oceanographic conditions. The objective of this work was to determine the relationship between deep-water (<200 m) scleractinian species richness along the western coast of the Americas, and four oceanographic variables (temperature, nitrates, phosphates and silicates), and the feasibility to use this information to model effects of global warming on those associations. Data on coral distribution were gathered from bibliography and museum collections, while information on oceanographic conditions from 200 to 2000 m depth was obtained from NOAA atlases. Species richness, estimated for intervals of 5 degrees of latitude, was correlated with abiotic factors using the Spearman rank coefficient. In the Northern Hemisphere, total species richness was positively influenced by temperature, but negatively by nutrients. In contrast, there was no effect of those factors on coral diversity in the Southern Hemisphere. At the family level, high temperatures favored species richness of Caryophylliidae and Dendrophylliidae north of the Equator, but diversity was reduced in areas of high concentration of silicates. In the Southern Hemisphere, temperature was not associated with deep-water coral richness, but correlated negatively with diversity of Caryophylliidae. Nutrients also showed an inverse relationship with richness of the latter family. In the rest of the families analyzed, there was no apparent effect of oceanic conditions on species richness in the Southern Hemisphere. The results indicated that richness may be influenced by changes in oceanographic factors (especially temperature and silicate concentration). Then, it is feasible to develop numerical models to predict possible changes in deep-water coral diversity on the basis of scenarios from global warming models.