北美CHIHUAHUAN荒漠啮齿动物群落各物种种群生物量动态的比较研究

本文给出了北美Ｃｈｉｈｕａｈｕａｎ荒漠分属４科１０属的１７种啮齿动物生物量的时间序列资料,利用时间序列分析方法、均匀性的Ｓｈａｎｎｎｏｎ指数和季节性指标对该１７个物种的生物量动态的比较研究说明：优势种在群落总生物量稳定中起着主要作用,其余非优势物种则在优势种种群密度较低时弥补低生物量,使１７个物种种群能共存于同一群落之中,使处于复杂多变的荒漠生境中的啮齿动物的生物量保持相对稳定。扩散在维持这种稳定中有明显的作用。     

北美CHIHUAHUAN荒漠啮齿动物群落动态Ⅰ.年间变动和趋势

本文给出了北美Ｃｈｉｈｕａｈｕａｎ荒漠由４科１０属１７种啮齿动物组成的群落的物种数、单位面积个体数与生物量、物种多样性的Ｓｈａｎｎｏｎ与Ｓｉｍｐｓｏｎ指数和均匀性等６个生态学变量的时间序列资料,并通过分析这些生态时间序列的年间变动和趋势讨论了该群落的动态。结果是：１）各年间６个生态学变量均随物理环境而变化,个体数和生物量变化幅度较大,均匀性保持相对稳定;２）群落中１７个物种从未同时出现过,物种数的     

四川小相岭山系大熊猫种群及栖息地调查

小相岭山系是现存大熊猫种群数量最少的山系之一。根据全国第3次大熊猫及其栖息地调查结果,小相岭山系大熊猫栖息地分布在石棉、冕宁和九龙三县,栖息地总面积802.04 km²,大熊猫种群数量有32只。大熊猫在3个位于小相岭山系的自然保护区内种群数量和栖息地面积分别为:四川冶勒自然保护区9只,栖息地面积168.01 km²;四川栗子坪自然保护区14只,栖息地面积306.38 km²;四川贡嘎山自然保护区1只,栖息地面积15.19 km²。在3个保护区大熊猫栖息地总面积为489.58 km²,占各山系大熊猫栖息地总面积的61.05%;有大熊猫24只,占大熊猫种群数量的75.0%。小相岭山系大熊猫meta种群栖息地片段化比较严重,它由2个种群和2个孤立分布点组成。南北方向从成都至昆明的108国道以东的种群A有大熊猫13只,栖息地面积263.54 km², 完整性较好,大熊猫分布比较集中。108国道以西的种群B有大熊猫19只,栖息地面积为538.50 km²,栖息地破碎。该山系大熊猫数量少,栖息地片段化严重,需加强保护。
     

Dietary L-Arginine Supplementation Affects the Skeletal Longissimus Muscle Proteome in Finishing Pigs

Forty-eight Duroc x Landrace x Large White gilts were used to determine the relationship between proteome changes of longissimus muscle and intramuscular fat (IMF) content in arginine-supplemented pigs. Beginning at 60 kg BW, pigs were fed a corn- and soybean meal-based diet supplemented or not with 1% L-arginine until they reached a BW of 100 kg. Supplementation with 1% L-arginine did not affect the growth performance or carcass traits, while it increased IMF content by 32% (P < 0.01), it also decreased the drip loss at 48 h post-mortem and the b* meat color value at 24 h post-mortem; supplementation with 1% dietary L-arginine did not change the proportion of SFA and MUFA in muscle lipids. The proteome changes in longissimus muscle between the control and supplemented pigs showed that L-arginine significantly influenced the abundance of proteins related to energy metabolism, fiber type and structure. The increase in IMF content was positively correlated with the increased abundance of slow twitch troponin I (TNNI1) protein and negatively correlated with myosin heavy chain IIb (MyHC IIb) protein content. It is suggested that the proteome changes in longissimus muscle contributed to the greater IMF content in L-arginine supplemented pigs.     

Synthesis of poly(ε-caprolactone) by an immobilized lipase coated with ionic liquids in a solvent-free condition

Polycaprolactone (PCL) was synthesized by ring-opening polymerization of ε-caprolactone through two different enzymatic processes. The lipase from Candida antarctica B, immobilized on macroporous acrylic acid beads, was employed either untreated or coated with small amounts of ionic liquids (ILs). Monocationic ionic liquids, [C _n MIm][NTf₂] (n = 2, 6, 12), as well as a dicationic ionic liquid, ([C₄(C₆Im)₂][NTf₂]₂), were used to coat the immobilized lipase and also as the reaction medium. In both methods, the polarity, anion of the ILs concentration and viscosity strongly influenced the reaction. Coating the immobilized enzyme with ILs improved catalytic activity and less ILs was required to produce PCL with a higher molecular weight and reaction yield. At 60 °C and ILs/Novozyme-435 coating ratio of 3:1 (w/w) for 48 h, the highest M _w and reaction yield of PCL were 35,600 g/mol and 62 % in the case of [C₁₂MIm][NTf₂], while the M _w and reaction yield of PCL was 20,300 g/mol and 54 % with [C₁₂MIm][NTf₂] and catalyzed by untreated lipase.     

川西平原农田啮齿动物群落动态：趋势和周期性

本用时间序列分析方法,对川西平原农田由8种啮齿动物组成的生物量、物种多样性的Shannon指数和Simpson指数中3个主要群落变量的趋势和周期性进行了分析和比较!结果表明：(1)3个变量都有增加的趋势．生物量是二次抛物线,Shannon指数是指数函数,Simpson指数是正弦函数。(2)3个变量中生物量显示出了周期性,这个变量的周期都约为1年。1年的周期与四川亚热带农业生态系统初级生产力的动态相一致：Shannon指数和Simpson指数末显示出周期性—川西平原啮齿动物群落3个变量的增加趋势,可能是农业生态系统中啮齿动物与人类长期共存所形成的适应特征,它们能随农业产量增加这样的环境变化使各个群落变量呈现出增加的趋势;也可能不过是处于群落自然波动中的上升阶段、因此需要长时间的研究工作,才能判断该增加趋势的生态学本质。     

川西平原大足鼠的种群生态学Ⅰ.种群动态和个体大小

我们利用标志重捕、夹捕解剖和笼养等三种方法于１９８９年１月至１９９５年６月对川西平原的大足鼠的种群密度、个体大小、生长和生物量进行了研究。种群密度最高１１．３只／ｈａ,最低０．７只／ｈａ,平均３．６只／ｈａ,并显示出与农作物相同的季节变动特征。雌雄性比由幼年组和亚成体组约１：１到成体组１：０．７８到老年组１：０．５３。雌雄个体的平均质量分别为１３６ｇ和１１４ｇ,两性的个体质量和后足长有明显差异,体长和耳长差异不明显。饲养的幼体及亚成体个体质量和尾长均持续增长,并可分别用Ｌｏｇｉｓｔｉｃ和对数方程较好地拟合。生物量则显示出比种群密度和个体质量更稳定的特征。     

北美CHIHUAHUAN荒漠11种啮齿动物种群密度季节性和周期性的比较研究

本文提出了季节性指标并用时间序列方法分析和比较了北美Chihuahuan荒漠11种啮齿动物种群密度的季节性、趋势和周期性。结果表明,研究期各年间盘尼西拉特斯颊囊鼠(C.p-enicillatus)有最显著的季节性,鹿鼠属(Peromyscus)的两个物种和伏拉瓦斯囊鼠(Pg.flav-us)的季节性最无规律;11个种群中有7个有趋势,除旗尾更格卢鼠(D.spectabilis)的种群密度呈减少趋势外,其余6个种群的密度呈增加的趋势;种群密度的周期,麦利阿姆更格卢鼠(D.merriami)是4年,曼利卡拉特斯鹿鼠(P.maniculatus)是4.5年,盘尼西拉特斯颊囊鼠(C.penicillatus)等3个种群是1年。对11个种群的比较说明,这些种群密度的季节性、趋势和周期性呈现出明显的多样化,且与它们的亲缘关系或种系发生历史无显著关系。11个种群的密度变动的多样化维持了它们在时间方面的共存。