生态学报  2014, Vol. 34 Issue (3): 564-571

文章信息

林琳, 曹梦婷, 胡益林, 黄丽丽, 李洲, 柳劲松
LIN Lin, CAO Mengting, HU Yilin, HUANG Lili, LI Zhou, LIU Jinsong
环境温度对白头鹎代谢产热和蒸发失水的影响
Effect of environmental temperature on thermogenesis and evaporative water loss in Chinese bulbuls (Pycnonotus sinensis)
生态学报, 2014, 34(3): 564-571
Acta Ecologica Sinica, 2014, 34(3): 564-571
http://dx.doi.org/10.5846/stxb201209061259

文章历史

收稿日期:2012-9-6
修订日期:2013-3-4
环境温度对白头鹎代谢产热和蒸发失水的影响
林琳1, 曹梦婷1, 胡益林1, 黄丽丽1, 李洲1, 柳劲松1, 2     
1. 温州大学生命与环境科学学院, 温州 325035;
2. 温州大学应用生态研究所, 温州 325035
摘要:基础代谢率(BMR)是恒温动物维持正常生理机能的最小产热速率,是动物在清醒时维持身体各项基本功能所需的最小能量值。“能量需求”假设认为,鸟类短期BMR的调整可以通过改变内部器官的大小来适应能量需求。以白头鹎(Pycnonotus sinensis)为研究对象,分别在10℃和30℃的不同环境中适应4周后,测定了其BMR、蒸发失水(EWL)和内部器官(心、肝、肾、胃、小肠和整体消化道)的重量,同时分析了白头鹎内部器官的变化及与BMR的关系。驯化4周后,白头鹎暖温组(30℃)的体重有明显降低的趋势;经协方差校正体重后,低温组(10℃)单位体重BMR与整体BMR明显高于暖温组,同时两组间EWL表现出显著差异。协方差分析表明,低温组白头鹎的肝脏、肾脏、小肠及总消化道重量显著高于暖温组。低温引起白头鹎能量需求增加,内部器官发生相应改变,要求摄入更多的氧气以维持代谢平衡,导致散失更多的蒸发水。
关键词白头鹎    环境温度    基础代谢率    蒸发失水    
Effect of environmental temperature on thermogenesis and evaporative water loss in Chinese bulbuls (Pycnonotus sinensis)
LIN Lin1, CAO Mengting1, HU Yilin1, HUANG Lili1, LI Zhou1, LIU Jinsong1, 2     
1. School of Life and Environmental Sciences, Wenzhou University, Wenzhou 325035, China;
2. Institute of Applied Ecology, Wenzhou University, Wenzhou 325035, China
Abstract:Studies examining an organism's response to environment change can yield insight into the adaptive value of phenotypic adjustments. It has been well believed that flexibility in a certain trait is adaptively and functionally important for organisms to cope with environment change. Basal metabolic rate (BMR) plays an important role in energy balance regulation in both small mammals and birds. The hypotheses of‘energy demand’of short-term adjustments in BMR proposes that birds are able to adjust the size of internal organs to cope with changes in food intake. In the present study, we examined the effect of temperature on BMR and evaporative water loss (EWL) in Chinese bulbuls (Pycnonotus sinensis). Birds were housed individually in cages (60 cm×60 cm×30 cm) under a 12L : 12D photoperiod at room temperature. Food and water were provided ad libitum. Subjects were adapted to the cages for at least one week, and then randomly assigned into either cold group, birds were exposed to 10 ℃ for 28 days or warm group, during which birds were exposed to 30 ℃ for 28 days. Metabolic rates (MR) and water content of air were measured using an open-circuit respirometry system (AEI technologies S-3A/I, USA) before and after the experiment. A‘U’tube (containing silica gel) was connected in series following the respiratory chamber and was weighed before the start and at the end of each measurement. After BMR measurements, birds were killed by decapitation and heart, liver, kidneys, gizzard, small intestine and total digestive tract were removed separately and weighed (to 0.1 mg). These organs were dried at 60 ℃ for 2 days to constant mass and weighed again (to 0.1 mg). BMR were (4.42±0.16) mL O2 /g·h at 10 ℃ and (3.75±0.16) mL O2 /g·h at 30 ℃. Difference in BMR after corrected for body mass was significant. When expressed as total BMR per bird (O2/h) it was also significant between the two groups. EWL averaged (0.30 ±0.02) (g H2O/h) at 10 ℃ and (0.22 ±0.03) (g H2O/h) at 30 ℃, and birds at 10 ℃ showed 36.4% EWL higher than at 30 ℃ (P <0.05). In addition, birds at 10 ℃ had significantly larger sizes in liver, kidney, small intestine and total digestive tract than at 30 ℃. It suggests that energy requirements significantly increase in Chinese bulbuls at cold compared with birds at warm, which is likely associated with the increased sizes in the internal organs and digestive tracts. A significant elevation of evaporative water at cold may be partly due to the increase in oxygen consumption.
Key words: chinese bulbuls (Pycnonotus sinensis)    environmental temperature    basal metabolic rate (BMR)    evaporative water loss (EWL)    

陆生内温动物(Endotherms)需花费大量的能量用于维持生命所需的化学进程(生理活动),并通过呼吸、皮肤及粪便等途径丢失水分。人们发现即使在标准的实验室条件下,内温动物依然表现出较大的能量花费及失水量的变化[1]。在鸟类中,能量花费水平与失水量受到环境[2, 3]、季节[4]及生存压力[5]变化的影响,温度就是其中重要的影响因子之一[6]

基础代谢率(BMR)和蒸发失水(EWL)是被广泛用于测定不同环境条件或不同时间段内鸟类种内和/或种间能量花费和失水量的两个重要指标[7]。目前已有很多研究证明,鸟类BMR水平会随外界环境温度的改变而做出相应变化,其中低温环境中鸟类的BMR较高温环境条件高[8, 9]。鸟类EWL包括呼吸失水(RWL)与皮肤失水(CWL),是水代谢中失水的重要途径[10]。研究发现戴胜百灵(Alaemon alaudipes)、漠百灵(Ammomanes deserti)和角百灵(Eremophila alpestris)等小型鸟类在环境温度为25℃条件下的EWL可高达70%—80%[11, 12]。而水分的丢失往往伴随着热量的散发,使得EWL在鸟类的热量平衡中起着重要作用,尤其是对生活在高温、水资源匮乏的地区的鸟类及一些迁徙鸟类来说显得更为重要[7]。一些日间活动的沙漠鸟类通过呼吸道和皮肤散失水分调节体温低于致死温度,获得生存[13]。目前有关鸟类的EWL研究主要以沙漠等高温干燥地区鸟类为主,且以自然生存条件进行的实验居多,而以实验室条件下环境因子控制影响的研究相对较少[6, 14, 15]

动物的BMR是肝脏、心脏及肾脏等代谢活性器官及肌肉组织等代谢率的总和[16, 17]。从生物进化角度来说,一个器官的功能结构应与能量需求相匹配,回应能量需求变化而做出适应调节[18]。Swanson[19]指出动物BMR的变化可由身体组分或特定组织的代谢强度的调节所导致身体组分或器官大小(重量)与代谢特征这种灵活变化是其成功应对在多变的环境条件而获得生存的重要手段,器官的这种表型可塑性(phenotypic flexibility)也是脊椎动物适应环境的普遍及典型的适应方式[20]。根据这一假设,基础代谢反映了那些产生高代谢率的组织或器官的维持消耗,这些器官可能包括把能量转化为可利用形式的器官——肝脏,能量运输器官——心脏和排泄最终废物的器官——肾脏等[21]

白头鹎(Pycnonotus sinensis)为留鸟,属雀形目(Passeriformes)鹎科(Pycnonotidae)。世界分布于欧亚大陆及非洲北部、中南半岛。在我国主要分布于东南沿海地区、太平洋诸岛屿。西起四川、云南东北部;东至沿海一带,包括海南和台湾;北达陕西南部及河南;南及广西西南等地。白头鹎在浙江省是一种最常见的雀形目鸟类之一[22]。已发现白头鹎具有较高的体温、较低的BMR和较宽的热中性区[23],其代谢产热存在明显的昼夜节律和季节性变化[24, 25]。内部器官(如肝脏、心脏、肾脏和消化道)及肌肉重量都与BMR的大小呈正相关,肝脏和肌肉的线粒体呼吸,肝脏和肌肉的细胞色素C氧化酶(cytochrome c oxidase,COX)活力及甲状腺激素冬季明显高于夏季,显示出白头鹎在季节性驯化过程中从整体、器官到生理和生化的可塑性变化[26, 27, 28, 29]。伴随全球气候的变暖,白头鹎有向北方扩散的趋势,目前发现白头鹎以扩散至东北等地[30]

目前国外已有较多关于鸟类EWL的报道[7, 14, 31, 32, 33],但国内有关动物EWL的研究主要见于小型啮齿动物领域[34, 35, 36, 37, 38],而在鸟类中尚未见有这方面的研究报道。为进一步了解环境因子对鸟类EWL影响,本研究以小型鸟类白头鹎为实验对象,测定不同环境温度下的BMR、EWL和器官重量,试图揭示白头鹎在适应不同环境温度过程中产热调节与EWL、内部器官变化与产热代谢之间存在的可能联系及对体温调节的意义。我们推测,低温可能引起白头鹎能量需求增加,相应的引起内部产热器官发生改变,要求摄入更多的氧气以维持平衡,使白头鹎通气量增加,导致散失更多的蒸发水。

1 实验材料与方法 1.1 实验动物

16只白头鹎(5♂,11♀)于2010年3月捕自浙江省温州地区(27°29′N,120°51′E)。将白头鹎标记并单笼(60 cm×60 cm×30 cm)饲养于温州大学动物实验房,进行自然光照、室温的环境条件下自由取食及饮水。该地区气候温暖,年平均降雨量可达1700mm,每季均有降雨,其中以春、冬两季降雨量较高。冬季(1月)和夏季(7月)的气温分别为8℃和32℃。适应1周待体重稳定后,将白头鹎随机分为低温组(10℃)与暖温组(30℃)(与冬季和夏季相近的两个温度),每组8只,分别于温州大学人工气候室中驯化4周(其中光照时间为:12L ∶ 12D)。

1.2 体温和体重的测定

测定驯化前(第0天)及其后每周的第7天白头鹎的体温和体重。体温采用北京师范大学司南仪器厂生产的便携式数字式温度测量仪测定(TH-212,精确度为0.1℃)。将温度计插入白头鹎泄殖腔内约1.5cm处,待温度计示数稳定后记录其体温。体重的测定采用梅特勒-托利多仪器(上海)有限公司生产的电子天平(PL3001-S,精确度为0.1g)。

1.3 基础代谢率(BMR)的测定

代谢率以每小时单位体重的耗氧量[mL O2 g-1 h-1]及每小时整体耗氧量[mL O2 / h]表示。耗氧量采用开放式氧气分析仪测定(S-3A/I,美国)。呼吸室体积为3.6 L,人工气候箱(BIC-250,北京)控制呼吸室实验温度(30±0.5)℃[24]。BMR的测定每天在9:00—19:00时间进行。动物实验前禁食3 h,放入呼吸室内适应1 h后开始测定耗氧量,共测定1 h,选择一段连续的,稳定的最低值计算BMR。每次实验前后称量鸟的体重并测定泄殖腔温度。

1.4 蒸发失水(EWL)测定

在测定BMR的同时测定EWL,待BMR出现稳定值后,将预先称重(精确至0.1mg)并装有干燥硅胶的“U”型管接在呼吸室后,连续测定1 h,实验前后干燥剂重量差即为EWL。若鸟在测定期间有排泄现象,则数据作废。

1.5 器官重量的测定

BMR测定结束后,隔日将动物断颈处死,迅速取出心、肝、肺、肾及消化道,并将消化道各部小心分离,剔除肠系膜和脂肪组织,然后纵剖,用生理盐水洗净内容物,滤纸吸干,用电子天平(瑞士梅特勒,0.1mg)称取重量记为湿重。然后将各器官、组织置于60℃烘箱内烘至恒重,称量记为干重。

1.6 数据

利用SPSS统计软件包进行相关数据统计分析。组间体重比较采用t检验分析,组间代谢率、EWL及内部器官重量均采用协方差分析(体重为协变量);组内各变量差异均采用单因素方差分析;EWL与单位体重代谢率相关性采用线性回归分析。文中数据均以平均值±标准误(Mean±SE)表示,P<0.05即认为差异显著。

2 结果 2.1 体温和体重

实验期间低温组(10℃)和暖温组(30℃)白头鹎的体温分别为(40.7±0.4)和(40.9±0.2)℃,二者无显著差异(t=0.392,P>0.05)。实验前,低温组和暖温组白头鹎的体重分别为(28.8±0.8)和(28.5±0.9)g,二者无显著差异(t=0.223,P>0.05)。随着驯化时间的延长,低温组白头鹎组内体重基本保持稳定,而暖温组体重却表现出明显的下降趋势(r2=0.481,P<0.02),第28天暖温组体重(25.6±0.6)g较实验前下降了10.1%。两组白头鹎组间体重在第28天出现显著差异(t=2.371,P<0.05),其中低温组白头鹎体重(27.7±0.6)g较暖温组高出8.2%(图1)。

图1 环境温度对白头鹎体重的影响 Fig.1 Effects of environmental temperature on body mass in Chinese bulbul 数据为平均值±标准误; * P<0.05
2.2 基础代谢率(BMR)

温度驯化4周后,白头鹎单位体重BMR与整体BMR经协方差校正体重后,均出现显著差异(单位体重BMR:F1,13=7.706,P<0.05;整体BMR:F1,13=6.762,P<0.05)。其中低温组单位体重BMR(4.42±0.16)(mL O2 g-1 h-1)和整体BMR(119.58±4.45)(mL O2 /h)分别较暖温组单位体重BMR(3.75±0.16)(mL O2 g-1 h-1)与整体BMR(101.86±4.45)(mL O2 /h)分别高出17.8%与17.4%(图2)。

图2 温度对白头鹎代谢率的影响 Fig.2 Effects of temperature on metabolic rate in Chinese bulbul 数据为平均值±标准误; * P<0.05
2.3 蒸发失水(EWL)

低温组与暖温组白头鹎的EWL分别为(0.30±0.02) g H2O/h与(0.22±0.03) g H2O/h,其中低温组较暖温组高出36.4%。经体重协方差分析,两组间EWL表现出显著差异(F1,13=7.577,P<0.05)(图3)。

图3 温度对白头鹎蒸发失水的影响 Fig.3 Effects of temperature on evaporative water loss in Chinese bulbul

具有较高的单位体重BMR白头鹎趋向于具有较高的EWL,其中单位体重BMR与EWL的线性回归方程为:EWL= -0.089+0.125BMR(r2=0.362,P<0.05)(图4)。

图4 白头鹎蒸发失水与代谢率的相关性 Fig.4 The relationship between evaporative water loss (g H2O /h) and basal metabolic rate (mL O2 / h ) of Chinese bulbul in temperature acclimation
2.4 器官重量

方差分析表明肝脏重量在温度驯化中发生显著变化(F1,13=8.328,P<0.05),低温组肝脏的重量是暖温组的1.3倍,但相关分析表明肝脏的重量与BMR之间相关不显著(r2=0.174,P>0.05)(图5)。

图5 温度驯化中白头鹎BMR与各器官重量的相关性 Fig.5 The relationship between basal metabolic rate and organ mass of Chinese bulbul in temperature acclimation

肾脏受温度驯化的影响也较大(F1,13=9.557,P<0.01),低温组肾脏重量显著高于暖温组,相关分析显示肾脏重量与BMR显著相关(r2=0.311,P<0.05)(图5)。

温度驯化对小肠重量有显著影响(F1,13=16.061,P<0.01),低温组白头鹎的小肠重量是暖温组的1.4倍。小肠重量与BMR显著相关(r2=0.507,P<0.01)(图5)。

整体消化道重量也存在显著变化(F1,13=16.291,P<0.01),低温组整体消化道重量显著高于暖温组。相关分析显示整体消化道重量对BMR的大小有显著影响(r2=0.384,P<0.05)(图5)。

3 讨论

体重是反映动物能量储备及营养状态的综合指标,与动物BMR都存在异速增长关系[3]。本次实验发现,随驯化时间的延长,低温组白头鹎体重保持不变,而暖温组体重逐渐降低,并在第28天出现显著差异(低温组比暖温组高出8.2%)。另外,低温组白头鹎单位体重BMR及整体BMR经体重校正后显著高于暖温组(分别高出17.8%与17.4%),表明温度影响了白头鹎BMR水平,在低温条件下白头鹎具有更高的BMR。低温条件下,为维持高且恒定的体温,提高能量代谢水平是小型鸟类的重要适应策略,这在很多鸟类如棕斑鸠(Streptopelia Senegalensis)、黑喉石鵖(Saxicola torquata)、云雀(Alauda arvensis)和林百灵(Lullula arborea)的温度驯化实验研究中得到证实[39, 40, 41]。在自然环境中,冬季是小型鸟类一个高能量消耗与高压力的时期,相应的BMR也呈现出较高的水平,一般较夏季高出15%—25%[42, 43],出现类似于生活在寒冷地带地区的小型鸟类BMR往往较热带地区高的现象[3, 44, 45]

肝脏是动物最重要的产热器官之一,消化道是食物消化吸收和能量转换活跃的代谢场所,肾脏是维持体内稳定、排泄代谢废物和促使新陈代谢正常进行的部位,在鸟类中这些代谢器官具有较高的单位质量代谢率,从而使得鸟类表现出较高的单位质量BMR[46]。本研究中,发现白头鹎代谢活性器官(肝脏、肾脏、小肠等)受到温度的显著影响,在低温条件下,白头鹎代谢活性器官重量较高,这一结果与张国凯等[28]和郑蔚虹等[29]报道的结果相一致,认为白头鹎体内存在代谢活性器官,这些器官组织具有很高的代谢活性,是白头鹎BMR的主要决定因素之一相一致。Williams和Tieleman报道了拟戴胜百灵(Alaemon alaudipes)在低温环境中表现出肝脏、肾脏及小肠重量的增加[6]。低温环境中,白头鹎需要较高的BMR水平以维持恒定的高体温,而高的代谢活性器官促成了BMR的提高,最终BMR变化表现出了与器官重量变化相一致的水平[17]。促进鸟类基础代谢产热增加的机制可以表现为多个层次,包括代谢器官的调整(adjustments in organ masses)、底物转运能力的调整(adjustments in transport capacities for substrates)和特殊器官的代谢强度的调整(adjustments in metabolic intensities of specific organ)等[19, 41]。冬季白头鹎可以通过形态、生理和生化的改变来适应外界环境,可以通过增加肝脏和肌肉的线粒体呼吸及COX活力来提高产热能力以适应冬季的环境条件[28, 29]。本文研究结果显示白头鹎肝脏及肌肉线粒体的状态4呼吸及细胞色素C氧化酶(cytochrome c oxidase,COX)在温度驯化中也表现出类似的变化,其中低温组肝脏线粒体状态4呼吸((43.94±3.09) nmol O2 / min·mg mitochondrial protein)及COX((57.25±4.96) nmol O2 / min·mg mitochondrial protein)分别是暖温组线粒体状态4呼吸(34.74±2.05)及COX(44.15±2.76)的1.26和1.29倍;低温组肌肉线粒体状态4呼吸((94.74±15.50) nmol O2 / min·mg mitochondrial protein)及COX(79.04±6.28 nmol O2 / min·mg mitochondrial protein)分别是暖温组线粒体状态4呼吸(82.26±10.86)及COX(57.26±7.03)的1.15和1.38倍,可以从生理和生化水平部分解释温度对白头鹎BMR的影响。

EWL在鸟类的热量平衡中有着重要作用,其变化是调节鸟类体温平衡的重要措施之一。目前有关鸟类EWL的报道主要见于对生活在高温、干燥环境中的鸟类研究[2, 6, 15, 47]。水分是生命活动的必要因素,尤其对生活于沙漠及干燥等环境中动物的生存有着重要关键的作用[48]。高温环境中,调节体温平衡成为鸟类生存的关键,当环境空气温度过高,EWL调节无法满足维持体温恒定是导致一些沙漠鸟类死亡的重要原因,可见EWL在鸟类体温调节中占十分重要的地位[49]

在自然环境中,生活于干燥环境的鸟类代谢率往往要较潮湿环境鸟类低,可能是对减少水分蒸发,维持体温的一种生存适应[14, 48],如生活于炎热干燥地区的拟戴胜百灵(Alaemon alaudipes)与图氏沙百灵(Eremalauda dunni)BMR与EWL分别较潮湿地区云雀(Alauda arvensis)和林百灵分别低43%与27%[48],这些结果都表明鸟类代谢率与EWL存在着正相关联系。然而,也有研究表明,在一定范围的环境温度中,鸟类EWL会随着温度的升高而增加,如Tieleman和Williams[31]发现阿拉伯沙漠地区拟戴胜百灵、图氏沙百灵及木百灵在环境温度从最适温度升至45℃时,百灵的EWL呈现明显增加,这可能与鸟类在过度高温环境下通过调节水分蒸发降低体温有关。在过度高温环境中,鸟类面临十分严峻的水分平衡问题,即使在水分供应短缺情况下,但为了防止体温过高,维持体温在恒定范围,鸟类仍会采取增加EWL来降低体温获得生存。

在本研究中,发现具有较高BMR水平的白头鹎同时呈现较高的EWL水平。然而目前有关BMR与EWL之间的关系尚不清楚,但有一种猜测认为,较高的代谢率会促使通气量增加,而伴随着呼吸频率的增加,引起RWL的增加,最终导致EWL升高[6]。本实验中,白头鹎经不同环境温度驯化表现出不同的EWL水平,其中低温组白头鹎的EWL较暖温组高出36.4%,同时我们还发现白头鹎单位体重BMR与EWL呈正相关性,说明温度影响了白头鹎EWL,低温条件下白头鹎较高的代谢率可能是其具有较高EWL水平的原因之一。类似结果在其他鸟类的研究中也见有报道Williams和Tieleman[6]在研究拟戴胜百灵时发现,15℃组百灵与36℃组相比较,表现出较高的BMR水平和较大的EWL量。

鸟类的基础产热受其自身生理需要及环境各因子共同影响,有关器官水平、细胞水平及酶学水平的产热研究可以加深对鸟类基础代谢调节的理解,同时有助于人们了解鸟类适应外界环境变化的相关生理适应对策。不同环境温度对白头鹎BMR、内部器官及EWL有明显影响,低温条件下可以提高白头鹎的代谢率、代谢活性器官与EWL,较高的代谢率可能是导致较高水平EWL的原因,而暖温条件下(30℃)白头鹎逐渐降低代谢产热可能是其为减少水分蒸发,保持水分的一种适应方式,最终使得白头鹎达到体温平衡适应环境。

参考文献
[1] Tieleman B I, Williams J B, Buschur M E, Brown C R. Phenotypic variation of larks along an aridity gradient: are desert birds more flexible? Ecology, 2003, 84 (7): 1800-1815.
[2] Tieleman B I, Williams J B, Bloomer P. Adaptation of metabolism and evaporative water loss along an aridity gradient. Proceeding of the Royal Society B, 2003, 270 (1511): 207-214.
[3] McNab B K. Ecological factors affect the level and scaling of avian BMR. Comparative Biochemistry and Physiology A, 2009, 152 (1): 22-45.
[4] Webster M D, Weathers W W. Seasonal changes in energy and water use by verdins, Auriparus flaviceps. Journal of Experimental Biology, 2000, 203 (21): 3333-3344.
[5] Wiersma P, Salomons H M, Verhulst S. Metabolic adjustments to increasing foraging costs of starlings in a closed economy. Journal of Experimental Biology, 2005, 208 (21): 4099-4108.
[6] Williams J B, Tieleman B I. Flexibility in basal metabolic rate and evaporative water loss among hoopoe larks exposed to different environmental temperatures. Journal of Experimental Biology, 2000, 203 (20): 3153-3159.
[7] Versteegh M A, Helm B, Dingemanse N J, Tieleman B I. 2008. Repeatability and individual correlates of basal metabolic rate and total evaporative water loss in birds: A case study in European stonechats. Comparative Biochemistry and Physiology A, 2008, 150 (4): 452-457.
[8] Nzama S N, Downs C T, Brown M. Seasonal variation in the metabolism-temperature relation of House Sparrow (Passer domesticus ) in KwaZulu-Natal, South Africa. Journal of Thermal Biology, 2010, 35 (2): 100-104.
[9] Song Z G, Wang D H. Basal metabolic rate and organ size in Brandt's voles (Lasiopodomys brandtii): Effects of photoperiod, temperature and diet quality. Physiology and Behavior, 2006, 89 (5): 704-710.
[10] Lee P, Schmidt-Nielsen K. 1971. Respiratory and cutaneous evaporation in the zebra finch: effect on water balance. American Journal of Physiology, 1971, 220 (6): 1598-1605.
[11] Dawson W R, William R. Evaporative losses of water by birds. Comparative Biochemistry and Physiology A, 1982, 71 (4): 495-509.
[12] Williams J B. A phylogenetic perspective of evaporative water loss in birds. The Auk, 1996, 113 (2): 457-472.
[13] Williams J B, Tieleman B I. Physiological adaptation in desert birds. Bioscience, 2005, 55 (5): 416-426.
[14] Michael H, Williams J B, Wertz P, Tieleman B I. Lipids of the stratum corneum vary with cutaneous water loss among larks along a temperature-moisture gradient. Physiological and Biochemical Zoology, 2003, 76 (6): 907-917.
[15] Muñoz-Garcia A, Williams B. Cutaneous water loss and lipids of the stratum corneum in Dusky antbirds, a lowland tropical bird. Condor, 2007, 109 (1): 59-66.
[16] Klaassen M, Oltrogge M, Trost L. Basal metabolic rate, food intake, and body mass in cold-and warm-acclimated Garden Warblers. Comparative Biochemistry and Physiology A, 2004, 137 (4): 639-647.
[17] Wang D H, Yang M, Liu Q S, Zhang Z Q, Zhang X Y, Chi Q S, Xu D L. Physiological ecology in small mammals and evolutionary theory. Acta Theriologica Sinica, 2009, 29 (4): 343-351.
[18] Liu J S, Li M. Phenotypic flexibility of metabolic rate and organ masses among tree sparrows, Passer montanus, in seasonal acclimatization. Acta Zoologica Sinica, 2006, 52 (3): 469-477.
[19] Swanson D L. Seasonal metabolic variation in birds: functional and mechnistic correlates// Thompson C F, ed. Current Ornithology Volume 17. Berlin: Springer + Business, 2010: 75-129.
[20] Piersma T, Lindström A. Rapid reversible changes in organ size as a component of adaptive behaviour. Trend in Ecology and Evolution, 1997, 12 (4): 134-138.
[21] Starck J M, Rahmaan G H A. Phenotypic flexibility of structure and function of the digestive system of Japanese quail. Journal of Experimental Biology, 2003, 206 (11): 1887-1897.
[22] Zheng G M, Zhang C Z. Birds in China. Beijing: China Forestry Publishing House, 2002.
[23] Zhang Y P, Liu J S, Hu X J, Yang Y, Chen L D. Metabolism and thermoregulation in two species of passerines from south-eastern China in summer. Acta Zoologica Sinica, 2006, 52 (4): 641-647.
[24] Zhou W, Wang Y P, Chen D H, Liu J S. Diurnal rhythms of Chinese bulbul (Pycnonotus sinensis) body temperature, body mass, and energy metabolism. Chinese Journal of Ecology, 2010, 29 (12): 2395-2400.
[25] Zheng W H, Liu J S, Jiang X H, Fang Y Y, Zhang G K. Seasonal variation on metabolism and thermoregulation in Chinese bulbul. Journal of Thermal Biology, 2008, 33 (6): 315-319.
[26] Peng L J, Tang X L, Liu J S, Meng H T. The effect of thyroid hormone on basal thermogenesis (Pycnonotus sinensis). Acta Ecologica Sinica, 2010, 30 (6): 1500-1507.
[27] Ni X Y, Lin L, Zhou F F, Wang X H, Liu J S. Effect of photoperiod on body mass, organ masses and energy metabolism in Chinese bulbul (Pycnonotus sinensis). Acta Ecologica Sinica, 2011, 31 (6): 1703-1713.
[28] Zhang G K, Fang Y Y, Jiang X H, Liu J S, Zhang Y P. Adaptive plasticity in metabolic rate and organ masses among Pycnonotus sinensis, in seasonal acclimatization. Chinese Journal of Zoology, 2008, 43 (4): 13-19.
[29] Zheng W H, Fang Y Y, Jiang X H, Zhang G K, Liu J S. Seasonal character in thermogenesis of liver and muscle in Chinese bulbul Pycnonotus sinensis. Zoological research, 2010, 31 (3): 319-327.
[30] Song Z M. 2006. A New bird record in Northeast: Pycnonotus sinensis. Journal of Mudanjiang Normal University: Natural Science, 54 (4): 1-2
[31] Tieleman B I, Williams J B. Cutaneous and respiratory water loss in larks from arid and mesic environments. Physiological and Biochemical Zoology, 2002, 75 (6): 590-599.
[32] Groff B, Muoz-Garcia A, Yamaguchi M, Williams J B. Development of skin structure and cutaneous water loss in nestling desert House Sparrows from Saudi Arabia. Comparative Biochemistry and Physiology A, 2007, 147 (2): 493-501.
[33] Ro J, Williams J B. 2010. Respiratory and cutaneous water loss of temperate-zone passerine birds. Comparative Biochemistry and Physiology A, 2010, 156 (2): 237-246.
[34] Wang D H, Wang Z W. Body temperature regulation and evaporative water loss in root vole (Microtus oeconomus). Acta Theriologica Sinica, 2000, 20 (1): 37-47.
[35] Wang D H, Sun R Y, Wang Z W. Evaporative water loss and thermoregulation in plateau pika (Ochotona curzoniae). Acta Theriologica Sinica, 1993,13 (2): 104-113.
[36] Zhu W L, Jia T, Lian X, Wang Z K. Evaporative water loss and energy metabolic in two small mammals, voles (Eothenomys miletus) and mice (Apodemus chevrieri), in Hengduan mountains region. Journal of Thermal Biology, 2008, 33 (6): 324-331.
[37] Zhu W L, Yang Y H, Jia T, Lian X, Wang Z K, Gong Z D, Guo X G. Evaporative water loss and body temperature regulation in Eothenomys miletus and Apodemus chevrieri. Acta Theriologica Sinica, 2008, 28 (1): 65-74.
[38] Zhu W L, Zhang L, Wang Z K. Thermogenic characteristics and evaporative water loss in the tree shrew (Tupaia belangeri ). Journal of Thermal Biology, 2010, 35 (6): 290-294.
[39] McKechnie A E, Chetty K, Lovegrove B G. Phenotypic flexibility in the basal metabolic rate of laughing doves: responses to short-term thermal acclimation. Journal of Experimental Biology, 2007, 210 (1): 97-106.
[40] Tieleman B I. Differences in the physiological responses to temperature among stonechats from three populations reared in a common environment. Comparative Biochemistry and Physiology A, 2007, 146 (2): 194-199.
[41] McKechnie A E. Phenotypic flexibility in basal metabolic rate and the changing view of avian physiological diversity: a review. Journal of Comparative Physiology B, 2008, 178 (3): 235-247.
[42] Zheng W H, Li M, Liu J S, Shao S L. Seasonal acclimatization of metabolism in Eurasian tree sparrows (Passer montanus). Comparative Biochemistry and Physiology A, 2008, 151 (4): 519-525.
[43] Liknes E T, Swanson D L. Phenotypic flexibility in passerine birds: Seasonal variation of aerobic enzyme activities in skeletal muscle. Journal of Thermal Biology, 2011, 36 (7): 430-436.
[44] Liu J S, Wang D H, Sun R Y. Climatic adaptations in metabolism of four species of small birds in China. Acta Zoologica Sinica, 2005, 51 (1): 24-30.
[45] Lin L, Wang L H, Liu J S. Metabolism and Thermoregulation in Crested Mynas (Acridotheres cristatellus). Chinese Journal of Zoology, 2010, 45 (5): 47-53.
[46] Daan S, Masman D, Groenewold A. 1990. Avian basal metabolic rates: their association with body composition and energy expenditure in nature. American Journal of Physiology, 1990, 25 (2): R333-340.
[47] Tieleman B I, Williams J B, Buschur M E. 2002. Physiological adjustments to arid and mesic environments in larks (Alaudidae). Physiological and Biochemical Zoology, 2002, 75 (3): 305-313.
[48] Muñoz-Garcia A, Williams B. Cutaneous water loss and lipids of the stratum corneum in house sparrows Passer domesticus from arid and mesic environments. Journal of Experimental Biology, 2005, 208 (19): 3689-3700.
[49] Serventy D L. Biology of desert birds // Farner D S, King J R, eds. Avian Biology. New York: Academic Press, 1971: 287-339.
[17] 王德华,杨明,刘全生,张志强,张学英,迟庆生,徐德立.小型哺乳动物生理生态学研究与进化思想.兽类学报,2009,29(4):343-351.
[24] 周围,王玉萍,陈德汉,柳劲松.白头鹎体温、体重及能量代谢的昼夜节律.生态学杂志,2010,29(12):2395-2400.
[26] 彭丽洁,唐小丽,柳劲松,孟海涛.甲状腺激素对白头鹎基础产热的影响.生态学报,2010,30(6):1500-1507.
[27] 倪小英,林琳,周菲菲,王小华,柳劲松.光周期对白头鹎(Pycnonotus sinensis)体重、器官重量和能量代谢的影响.生态学报,2011,31(6):1703-1713.
[28] 张国凯,方媛媛,姜雪华,柳劲松,张永普.白头鹎的代谢率与器官重量在季节驯化中的可塑性变化.动物学杂志,2008,43(4):13-19.
[29] 郑蔚虹,方媛媛,姜雪华,张国凯,柳劲松.白头鹎肝脏和肌肉冬夏两季的代谢产热特征比较.动物学研究,2010,31(3):319-327.
[30] 宋泽明.东北鸟类新记录——白头鹎.牡丹江师范学院学报:自然科学版,2006,54(4):1-2.
[34] 王德华,王祖望.高寒地区根田鼠的体温调节与蒸发失水.兽类学报,2000,20(1):37-47.
[35] 王德华,孙儒泳,王祖望.高原鼠兔蒸发失水的地位及热能调节.兽类学报,1993,13(2):104-113.
[37] 朱万龙,杨永宏,贾婷,练硝,王政昆,龚正达,郭宪国.横断山两种小型哺乳动物的蒸发失水与体温调节.兽类学报,2008,28(1):65-74.
[45] 林琳,王丽华,柳劲松.八哥的代谢产热特征及体温调节.动物学杂志,2010,45(5):47-53.