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能量代谢指动物在进行生理活动(如摄食、消化以及动物的活动等)时所消耗能量的总和,一般以动物的呼吸率利排泄率来估计动物的能量代谢。其主要研究内容是闸明生物能量代谢的基木规律以及与环境闪子的关系。菲律宾蛤仔(Ruditapesphil ippmarum)是我国一种重要的养殖贝类,关于其能量代谢的研究却较少,这种状况妨碍了菲律宾蛤仔养殖生态理论的完善和养殖技术的提高。本研究主要对菲律宾蛤仔呼吸率和排泄率的基本规律(能量代谢与体重的关系、能量代谢的昼夜变化)及其与环境因子(饵料浓度、水温、栖息底质环境)的关系进行探讨。研究结果如下:1.不同体重菲律宾蛤仔代谢率小同。实验川菲律宾蛤仔分三种大小:l(干肉重为0.07-0.14g)、ll(干肉重0.27-0.34g)、III(干肉重0.45~0.63g)。温度包括:26℃(八月)、20℃(十月)、1 5℃(十二月)、9℃(一月)。实验共设四个饵料浓度:2.28±0.25,6.454±0.44,10.284±0.82,15.414±1.56mgTPM/L(TPM,总颗粒物),饵料中POM(颗粒有机物)含量都为4.68±1.64 mg/L。常温下菲律宾蛤仔代谢率随着体重的增大而增大。15℃、20~C、26℃时蛤仔呼吸率与干肉重呈明显的幂函数关系R=aW~b,a值变动范围为0.1076-0.3309;b值变动范围为0.239l~0.8381;蛤仔排泄率与干肉重也呈明显的幂函数关系N=aW~b,a值变动范围为14.213~68.362:b值变动范围为0.3673-1.1 532。9℃(饵料浓度为2.28±0.25mgTPM/L)、20℃(饵料浓度为10.284-0.82mgTPM/L)、26℃(饵料浓度为6.454±0.44mgTPM/L)时不同体重蛤仔氧氮比差异显著,其它情况下不同体重蛤仔氧氮比差异不显著。2.常温下菲律宾蛤仔代谢率受饵料浓度的影响,不同大小蛤仔受饵料浓度的影响程度不同。I组蛤仔呼吸率受饵料浓度的显著影响,II组III组蛤仔呼吸率只在9℃(一月)和26~C(八月)时受饵料浓度的显著影响。26℃时影响最显著,26℃时I组蛤仔在饵料浓度为2.28±0.25,6.45±0.44,l0.28±0.82,15.4l±1.56mgTPM/L时呼吸率分别是O.086,0.146,0.073,0.093(mlO_2/h);ll组蛤仔在上述浓度饵料中呼吸率分别是0.138,0.214,0.J 26,0.12l(mlO_2/h);III组蛤仔在上述浓度饵料中呼吸率分别是0.129,0.266,0.186,0.192(mlO_2/h)。菲律宾蛤仔呼吸率在饵料浓度为6.45±0.44 mgTPM/L时最高,蛤仔呼吸率在其它饵料浓度时都会降低。菲律宾蛤仔排泄率在饵料浓度为10.28±0.82 mgTPM/L和15.4l士1.56mgTPM/L时显著高于其它浓度组,9℃时这种趋势更明显,9℃时饵料浓度为2.28±0.25,6.454±044,lO.284±0.82,15.41±1.56mgTPM/L中I组蛤仔排泄率分别是4.297,2.874,8.003,6.658(μgNH_3-N/h);II组蛤仔在上述浓度饵料中排泄率分别是4.011,3.609,10.427,12.732(μgNH_3-N/h);III组蛤仔在上述浓度饵料中排泄率分别是2.28 l,6.452,10.283,15.417(μgNH_3-N/h)。3.菲律宾蛤仔代谢率受自然温度的显著影Ⅱ向。I组蛤仔在9℃、15℃、20℃、26℃时呼吸率平均为0.057,0.085,0.039,O.099;II组蛤仔在上述四个温度中呼吸率平均为0.08,O.128,0.089,0.149(mlO_2/h),I组和II组蛤仔在9℃和20~C时呼吸率较低,在26℃时呼吸率最高。III组蛤仔在上述四个温度中呼吸率平均为0.09,O.1 59,O.143,O.193(mlO_2/h),在9℃时llI组蛤仔呼吸率显著低于其它温度组。温度为9℃、15℃、20℃、26℃时l组蛤仔排泄率平均为5.458,13.169,4.946,11.138(μgNH_3-N/h):II组蛤仔在上述温度中排泄率平均为7.695,23.578,8.319,23.90l(μgNH_3-N/h);III组蛤仔在上述温度中排泄率平均为11.738,27.443,15.658,35.407(μgNH_3-N/h),蛤仔排泄率在15℃和26℃时均高于9℃和20℃。4.摄食状态与饥饿状态菲律宾蛤仔代谢率有明显不同。26℃时蛤仔静止状态呼吸率平均为0.336(m102/g干重.h),摄食状态呼吸率平均为0.656(ml0_2干重.h),摄食状态呼吸率比静止状态平均升高了0 32(ml0_2/g干重.h);26℃时蛤仔静止状态排泄率平均为39.471(μgNH_3-N/g干重.h),摄食状态排泄率平均为88.08(μgNH_3-N/g干重.h),摄食状态排泄率比静止状态排泄率平均升高了48.6(μgNH_3-N/g干重.h)。摄食状态代谢率平均是静止状态的2~3倍。根据摄食引起的呼吸率和排泄率升高量得出每氧化产生lμgNH_3-N需0_2量平均为7.05μl。5.人工控制温度对菲律宾蛤仔代谢率有明显影响。不同大小蛤仔受温度的影响程度不同。在温度5℃、10℃、l 5℃、20℃、26℃,I组和II组蛤仔呼吸率都随着温度的升高而升高,在10℃~l5℃和20℃~26℃这二个温度变化范围内呼吸率变化最大,在20℃~26℃时I组蛤仔呼吸率变动范围为O.85~1.04(m10_2/g干重.h)、II组蛤仔变动范围为0.57~0.86(ml0_2/g干重.h)。III组蛤仔呼吸率只在5℃~l0℃时明显增高,变动范围为0.09~0.5l(m10_2/g干重.h),在10℃~26℃范围内变化不大。I组和II组蛤仔排泄率随着温度的升高而升高,变动幅度较大,在5℃~26℃范围内其排泄率变动范围为10.32~81.53(μgNH_3-N/g干重.h);而 III组蛤仔排泄率只在5℃~15℃时随着温度的升高而升高,其排泄率变动范围为6.75~23.77(μgNH_3-N/g干重.h),在15℃~26℃范围内几乎不变。III组蛤仔的适温范围比I组和II组蛤仔广。菲律宾蛤仔在5℃和10℃时氧氮比变化明显,变动范围为2.76~11.44,在15~26℃时变化不大。6.菲律宾蛤仔代谢率有明显的日节律性,呈正弦曲线型变化。蛤仔夜问代谢率明显升高。I组蛤仔夜间呼吸率平均为0.867(m10_2/g干重.h),白天呼吸率平均为O.504(m10_2/g干重.h);II组蛤仔夜间呼吸率平均为0.438(m10_2/g干重.h),白天呼吸率平均为0.36l(m102/g干重.h);III组蛤仔夜间呼吸率平均为0.409(m10_2/g干重.h),白天呼吸率平均为0.252(m102/g干重.h)。在22:00-23:00菲律宾蛤仔呼吸率最高。7.底质环境对菲律宾蛤仔的代谢率有明显影响。在饥饿状态下菲律宾蛤仔在泥沙底质中呼吸率平均为l 406(m10_2/g干重h),在无泥沙环境中呼吸率平均为O.963(ml0_2/g干重.h);摄食状态下菲律宾蛤仔在泥沙底质中呼吸率平均为1.59l(m102/g干重.h),在无泥沙环境中呼吸率平均为1.115(m10_2/g干重.h)。在饥饿状态下菲律宾蛤仔在泥沙底质中排泄率平均为78.934(μgNH_3-N/g 干重.h),在无泥沙环境巾排泄率平均为45.043(μgNH_3-N/g干重.h);摄食状态下菲律宾蛤仔在泥沙底质中排泄率平均为87.12l(μgNH_3-N/g干重.h),在无泥沙底质中排泄率平均为58.354(μgNH_3-N/g干重.h)。蛤仔在泥沙环境中呼吸率和排泄率都明显升高。

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The effects of the timing of initial feeding (0, 1, 2 3 and 4 days after yolk exhaustion) and temperature (15, 18 and 21degrees C) on the point-of-no-return (PNR), survival and growth of laboratory-reared Japanese flounder Paralichthys olivaceus larvae were studied under controlled conditions. The larvae reached PNR on 7(.)7, 5(.)2 and 4(.)2 days-post-hatching (dph) at 15, 18 and 2 V C, respectively. At each temperature, larval growth did not differ significantly among the delayed initial feedings 1 day before PNR but decreased significantly in larvae first fed after that. In the treatments where initial feeding was equally delayed, larvae grew significantly faster at 18 and 21degrees C than at 15degrees C. The larvae survived apparently better at 15 and 18degrees C than at 21degrees C when initial feeding was equally delayed. At each temperature, survival of the larvae first fed before PNR did not differ noticeably, while delayed initial feeding after that apparently reduced their survival. These results indicated that there existed a negatively temperature-dependent PNR in the Japanese flounder larvae. Survival and growth of the larvae strongly depended on temperature as well as the timing of initial feeding. High temperature accelerated the yolk exhaustion and growth of the larvae and thus reduced their starvation tolerance and survival. To avoid potential starvation mortality and obtain good growth, the Japanese flounder larvae must establish successful initial feeding within 2 days after yolk exhaustion at 15degrees C and within 1 day at both 18 and 21degrees C. (C) 2005 The Fisheries Society of the British Isles.

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Nutrient concentrations in seawater, and C, N, P, Si and chlorophyll a content in different-sized particulates were measured in Jiaozhou Bay, and C, N, P, Si composition in different-sized fractions of phytoplankton and their ecological responses to nutrient structure of the seawater were studied. Microphytoplankton and nanophytoplankton were dominant in Jiaozhou Bay. High C (16.50-20.97 unol L-1), N (2.46-2.99 mu mol L-1) and low P (0.06-0.12 mu mol L-1), Si (0.18-0.57 mu mol L-1) content, and high N/P (24.7-64.6) and low SUP (4.4-10.8), Si/N (0.06-0.20) ratios were found in all sized groups of particulates. These values reflected the elemental compositions of different-sized fractions of phytoplankton as being an ecological response to the nutrients in the seawater. The ratios deviated significantly from the Redfield values. The nutrient composition of seawater and particulates and their relationship to chlorophyll a showed that phytoplankton growth was possibly limited by Si. Si limitation appears favorable for controlling the ecological equilibrium of Jiaozhou Bay. Different-sized fractions of phytoplankton had different suitability to nutrient structures of the seawater. Among phytoplankton size groups, nanophytoplankton and microphytoplankton growths were more adaptable in eutrophic Jiaozhou Bay, and more competitive for assimilation of Si. This is consistent with their diatom-dominated composition, controlling the biomass and productivity of phytoplankton in Jiaozhou Bay. (c) 2006 Elsevier Ltd. All rights reserved.

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A natural lectin from the serum of the shrimp Litopenaeus vannamei was purified to homogeneity by a single-step affinity chromatography using fetuin-coupled agarose. The purified serum lectin (named LVL) showed a strong affinity for human A/B/O erythrocytes (RBC), mouse RBC, chicken RBC and its haemagglutinating (HA) activity was specifically dependent on Ca2+ and reversibly sensitive to EDTA. LVL inactive form had a molecular mass estimate of 172 kDa and was composed of two non-identical subunits (32 and 38 kDa) cross-linked by interchain disulphide bonds. Significant LVL activity was observed between pH 7 and 11. In HA-inhibition assays performed with several carbohydrates and glycoproteins, LVL showed a distinct and unique specificity for GalNAc/GluNAc/NeuAc which had an acetyl group, while glycoproteins fetuin and bovine submaxillary mucin (BSM) had sialic acid. Moreover, this agglutinin appeared to recognise the terminal N- and O-acetyl groups in the oligosaccharide chain of glycoconjugates. The HA activity of L. vannamei lectin was also susceptible to inhibition by lipopolysaccharides from diverse Gram-negative bacteria, which might indicate a significant in vivo role of this humoral agglutinin in the host immune response against bacterial infections. (C) 2006 Elsevier Ltd. All rights reserved.

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Chitosan (CS) with two different molecular weight were modified by reacting with methyl hydrazine-dithiocarboxylate and methyl phenylhydrazine-dithiocarboxylate to give 2-(hydrazine-thiosemicarbazone)-chitosan (2-HTCHCS, 2-HTCLCS) and 2-(phenylhydrazine-thiosemicarbazone)chitosan (2-PHTCHCS, 2-PHTCLCS). The structure of the derivatives was characterized by FT-IR spectroscopy and elemental analysis. The antioxidant activities of the derivatives were investigated employing various established systems, such as hydroxyl radical (*OH)/superoxide anion (O-2(center dot-)) scavenging/reducing power and chelating activity. All of the derivatives showed strong scavenging activity on hydroxyl radical than chitosan and ascorbic acid (Vc), and IC50 of 2-HTCHCS, 2-HTCLCS, 2-PHTCHCS and 2-PHTCLCS was 0.362, 0.263, 0.531 and 0.336 mg/mL respectively. The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were strong. The results showed that the superoxide radical scavenging effect of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan were higher than that of chitosan. The derivatives had obviously reducing power and chelating activity. The data obtained from vitro models clearly establish the antioxidant potency of 2-[phenylhydrazine (or hydrazine)-thiosemicarbazone]-chitosan. (C) 2010 Elsevier B.V. All rights reserved.

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用1-[2-(对甲苯磺酸酯)乙基]-2-苯基咪唑[4,5-f]9,10-菲(TSEPIP)作为柱前荧光衍生试剂,在Eclipse XDBC8(4.6×150 mm,5μm,Agilent)反相色谱柱上,采用梯度洗脱在检测波长为380nm(激发波长为260nm)的条件下,实现了阿拉斯加深海鱼油中饱和脂肪酸含量的外标法定量测定.26种饱和脂肪酸的线性范围是200.0pmol~48.83fmol,线性相关系数均大于0.9996,检测限为3.824~47.13 fmol(信噪比为3:1测得,S/N 3:1).经柱后串联质谱大气压化学电离源(APCI)正离子模式实现了各种饱和与不饱和脂肪酸衍生物的质谱鉴定,进而通过峰面积归一化法得出了所有饱和与不饱和脂肪酸的相对含量.结果表明,深海鱼油主要含有C12~C22的脂肪酸,共鉴定出25种脂肪酸,其中不饱和脂肪酸含量占69.71%(峰面积百分比,下同),特别是具有重要生理作用的多不饱和脂肪酸,如C20:5,8,11,14,17-二十碳五烯酸(5,8,11,14,17-eicosapentaenoic acid,EPA,16.62%),C22:6:2,5,8,11,14,17-二十二碳六烯酸(2,5,8,11,14,17-docosahexenoic acid,DHA,12.31%).

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利用2004年微气象观测资料,分析了海北高寒湿地长、短波辐射以及地表反射率(A)和光合有效辐射(PAR)占太阳总辐射(DR)比例(η)的变化特征。结果表明,海北高寒湿地长、短波辐射均具有明显的季节变化。DR在12月最低,4月最高。PAR在12月最低,7月最高。受下垫面性质影响,反射辐射(UR)和A在1~2月明显大于其他季节,7~10月小,A在植物生长季节的5~9月平均值为0.172,年平均值为0.299。地面长波辐射(DLR)、大气逆辐射(ULR)和净辐射(Rn)的最低值均出现在1月,最大值出现时期则不同,DLR与Rn均出现在6月,而ULR出现在8月。地面有效辐射(ELR)无明显的季节变化。叩的季节变化比较弱,7月最高值为0.434,1月最低值为0.316,年平均值为0.40。

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对甘肃省116份胡麻地方品种的重要品质指标--粗脂肪、硬脂酸、棕榈酸、油酸、亚油酸、亚麻酸含量和碘值进行测定,并根据这些品质指标对供试品种进行聚类分析.结果显示:(1)供试品种粗脂肪含量平均值为37.48%,变异系数3.8%;硬脂酸、油酸含量平均值分别为5.32%和29.05%,变异系数分别为19.5%和11.6%;棕榈酸、亚麻酸、亚油酸含量平均值分别为5.9%、48.76%、10.95%,变异系数分别为8.4%、8%、8%;平均碘价175.60,变异系数2.76%;(2)聚类分析结果显示,116个品种聚为7大类,其中:b亚组群硬脂酸和油酸含量最高,而亚麻酸含量最低;d亚组群品种亚麻酸含量最高;e亚组群粗脂肪含量和碘价最高,油酸含量最低;f亚组群硬脂酸含量最低;g亚组群棕榈酸含量最高,碘价最低.

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针对我国青藏高原草地大面积退化及由此引发的一系列生态环境问题,从土壤生态功能恢复和区域可持续发展的角度出发,将原生高寒嵩草草甸封育系统作为对照,研究了土地退化对土壤碳氮含最的影响,检验了不同人工重建措施(3个人工种植处理:混播、松耙单播、翻耕单播和1个自然恢复处理)对土壤碳含量的相对影响程度。研究结果如下:原生植被封育处理每平方米土壤平均碳、氮含量分别为7.47kg和0.647kg,而重度退化地碳、氮含量分别为3.67和0.448kg•m^-2.可以推算,由于土地退化而造成的土壤(0-20cm层)碳氮丢失量分别为3.80kg•m^-2和0.199kg•m^-2,即高寒草甸土地退化导致0~20cm土壤层中50.87%的有机碳和30.75%的氮流失,可以看出高寒草甸土壤退化后流失的碳比氮多;混播处理、松耙单播处理、翻耕单播处理和自然恢复处理土壤单位面积有机碳含量分别是原牛植被土壤有机碳的70.5%,69.0%,49.0%和80%,单位面积氮含量分别是原生植被土壤全氮的86.9%,88.7%,71.1%和91.7%。但是,与重度退化地相比,除翻耕单播处理外,其它恢复重建措施均能部分恢复系统的碳氮含量,因此,将重度退化地进行自然恢复或松耙混播重建多年生植被可以作为系统固定碳(碳汇)的一个途径。

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对青藏高原东北部两个不同海拔地点(互助,2460m和海北,3200m)的露蕊乌头Aconitum gymnandrum的传粉生态学进行了比较研究。研究结果表明高海拔居群的单花花期、雄性期持续时间、雌性期持续时间比低海拔长。露蕊乌头不存在无融合生殖现象,尽管高度自交亲和,但产生种子必须依赖传粉媒介。熊蜂是露蕊乌头的主要传粉昆虫,两个居群均存在传粉限制。熊蜂取食花蜜为主,在同一个花序上的访问顺序以由下向上为主,但在互助居群和海北居群有3.9%和2.7%的访花是由上向下进行的。统计发现有37.7%和29.3%的访问行为发生在同一植株内;因此,同株异花传粉造成的自交在露蕊乌头中仍然不能避免。低海拔居群的熊蜂种类和访花频率均高于高海拔居群,但自然状态下两个居群的结实率并没有显著差异。高海拔露蕊乌头居群可能具有较长的柱头持续时间,从而补偿了由于访花频率低带来的结实率降低。

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Precipitation is considered to be the primary resource limiting terrestrial biological activity in water-limited regions. Its overriding effect on the production of grassland is complex. In this paper, field data of 48 sites (including temperate meadow steppe,temperate steppe, temperate desert steppe and alpine meadow) were gathered from 31 published papers and monographs to analyze the relationship between above-ground net primary productivity (ANPP) and precipitation by the method of regression analysis. The results indicated that there was a great difference between spatial pattern and temporal pattern by which precipitation influenced grassland ANPP. Mean annual precipitation (MAP) was the main factor determining spatial distribution of grassland ANPP (r~2 = 0.61,P < 0.01); while temporally, no significant relationship was found between the variance of AN PP and inter-annual precipitation for the four types of grassland. However, after dividing annual precipitation into monthly value and taking time lag effect into account, the study found significant relationships between ANPP and precipitation. For the temperate meadow steppe, the key variable determining inter-annual change of ANPP was last August-May precipitation (r~2= 0.47, P = 0.01); for the temperate steppe, the key variable was July precipitation (r~2 = 0.36, P = 0.02); for the temperate desert steppe, the key variable was April-June precipitation (r~2 = 0.51, P <0.01); for the alpine meadow, the key variable was last September-May precipitation (r~2 = 0.29, P < 0.05). In comparison with analogous research, the study demonstrated that the key factor determining inter-annual changes of grassland ANPP was the cumulative precipitation in certain periods of that year or the previous year.

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对海北定位站地区分布的金露梅灌丛草甸、矮嵩草草甸和沼泽化藏嵩草草甸3种高寒植被类型群落及土壤环境因子的观测结果表明:3种植被类型地上年净生产量依次为矮嵩草草甸(339.594 g/m2)>沼泽化藏嵩草草甸(339.358 g/m2)>金露梅灌丛草甸(278.299 g/m2);光能利用率为矮嵩草草甸(0.099%)>沼泽化藏嵩草草甸(0.091%)>金露梅灌丛草甸(0.075%);植被群落的种类组成为矮嵩草草甸(54种)>金露梅灌丛草甸(47种)>沼泽化藏嵩草草甸(24种).观察矮嵩草草甸和金露梅灌丛草甸0~20 cm土壤温湿度表明,矮嵩草草甸土壤温度>金露梅灌丛草甸,土壤湿度则相反,其中矮嵩草草甸土壤温度较高,土壤湿度较低,金露梅灌丛草甸则是高土壤湿度和低土壤温度,而沼泽化藏嵩草草甸土壤湿度达饱和甚至超饱和状态,土壤温度显得更低.

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根据野外样地调查资料,采用丰富度指数、物种多样性指数和均匀度指数对青海湖乌岛沙地植物群落的多样性进行了研究,并用相关分析研究了多样性指数间的关系,结果表明:①鸟岛7个主要沙地群落间的植物多样性差异很大,分布于固定沙丘上的赖草、甘青铁线莲等群落均具有较高的丰富度指数、多样性指数,而西伯利亚要、藏虫实等分布在流动沙丘上的群落则最小,但均匀度指数最高。②从流动沙丘到固定沙丘阶段的变化过程中,丰富度指数、Shannon-Wiener指数和Simpson指数的变化趋势基本一致,而均匀度指数则呈相反趋势,半固定沙丘是这一变化的重要转折点。②物种在各沙地类型中出现频率的多样性指数差异很大,特有种多样性指数在固定沙丘中最高,占主导地位,而在流动沙丘阶段,普通种的物种多样性指数最高。④植物生活型上各沙丘类型上的物种多样性指数均以多年生草本为最高,其次为一年生草本,而且从流动沙丘至固定沙丘阶段呈递增变化。⑤丰富度指数与多样性指数、均匀度指数之间存在极显著的相关性。

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对祁连山海北高寒草甸地区近夏至日微气象观测分析表明: (1) 14:00 (北京时,下同) 太阳总辐射瞬时值最高可达1061 W·m-2 , 净辐射、反射辐射、光合有效辐射和紫外辐射分别为670、218、380 和168 W·m-2 , 分别约为太阳总辐射的58 %、20 %、36 %和14 % , 6 月下旬日平均反射率约为0. 22 ; (2) 土壤热通量、感热通量和潜热通量瞬时值最大分别为91、274 和362 W·m-2 , 相应占净辐射的比例为20 %、38 %和42 %; (3) 地—气温度在一定范围的水平和垂直方向变化较为剧烈, 大气逆温约出现于20 :00 至次日11 :00 , 午夜01 :00 最强; (4)风速阵性强, 有显著日变化的时间性分布。

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模拟高原低氧条件研究高原鼠兔肝细胞内质网(Endoplasmic reticulum , ER ) 和心肌肌浆网(Sarcoplasmic reticulum , SR) 钙泵功能变化。实验设对照组(海拔2 300 m ) 和两个低氧实验组(模拟海拔5 000m 和7 000m )。24 h 急性低氧时, 海拔5 000 m 组高原鼠兔ER 的Ca2+ 泵活性无变化, 海拔7 000 m 组高原鼠兔ER Ca2+泵活性下降29102%。7 d 亚急性低氧时高原鼠兔SR 的Ca2+泵活性无显著变化。高原鼠兔ER 的Ca2+泵活性在海拔5 000 m 组和7 000 m 组分别升高32.50% 和33.33%。25 d 慢性低氧时高原鼠兔ER , SR 的Ca2+ 泵活性均无显著变化.表明: 急性低氧对Ca2+泵功能有抑制作用, 低氧7 d 后抑制缓解, 至25 d 低氧时趋于恢复。