东灵山森林生态系统若干水分问题的研究

东灵山地区年均降水量659.7mm，单次降水以雨量小、雨强低的降水为主。水汽压（年均17.7mb）、相对湿度（年均66％）的季节变化呈现生长季高、冬季低的趋势。年均蒸发量1019.5mm;气温、风速、日照时间和水压与月蒸发量和日蒸量相关显著;气温、日照时间和水压分别在11-6月、7－8月和9－10月为决定蒸发量的首要因子。枯枝落叶层、土壤层湿度主要受前十日降水量和坡向影响。 植物体含水量生长季节较高，冬季较低;含水量随径级的增大而降低。六个灌木树种的平均含水量大小顺序为：毛榛（48.62%）最高荆条（36.32%）最低;七个乔木树种水分含量为油松，56.14%;蒙椴，54.19%;华北落叶松，52.91%;五角枫，43.64%;辽东栎，41.87%;棘皮桦，41.13%;大叶白腊，37.79%。几种植被类型的储水量为：辽东栎林，82.08mm;华北落叶松林，47.35mm;混交林，34.60mm;油松林，31.33mm;灌丛，12.40mm。各树种叶片日最低水势的季节均值为：辽东栎，-16.1bar;五角枫，-15.8bar;大叶白腊，-15.1bar;糠椴，-13.4bar;棘皮桦，-12.3bar;蒙椴，-12.2bar。叶片水势的日间变化均呈一“V”形曲线;光照在叶片水势的日间变化中起着决定性作用。 96年各树种平均单株树干茎流量为辽东栎，30.3mm(4.19%);华北落叶松，16.1mm(2.22%);油松，8.9mm(1.23%);棘皮桦，2.9mm(0.40%)。两个生长季各林分冠层的水量平衡为：辽东栎林，树干流茎量101.87mm(9.18%)，穿透降水量823.08mm(74.15%)，截留量185.05mm(16.67%);华北落叶松林，树干径流量66.88mm(6.03%)，穿透降水量836.92mm(75.40%)，截留量206.20mm(18.58);混交林，树干径流量50.13(4.52%)，穿透降水量846.78mm(76.29%)，截留量212.20mm(19.12%);油松林，树干径流量33.90mm(3.05%)，穿透降水量934.88mm(84.22%)，截留量141.22mm(12.72%)。多元回归分析表明，树干流茎量S与降水量P和前24小时降水量P_1呈显著正相关关系;穿透降水量T与降水量P和最大雨强M正相关显著。附加截留量与降水时间成正比。 枯枝落叶层的生物量为：油松林，25.56t/hm~2;华北落叶松林20.01t/hm~2;辽东栎林，8.31t/hm~2;混交林，7.98t/hm~2。枯枝落叶层的平均实际持水量和有效持水量均以油松林最大，其次是华北落叶松林，而混交林和辽东栎林较低;枯枝落叶层的实际持水量和有效持水量的季节变化分别与前十日降水量P10成正相关和负相关关系。枯枝落叶层的截留量为油松林＞华北落叶松林＞辽东栎林＞混交林;油松林（145.632mm和90.800mm）混交林(61.816mm和54.504mm)。油松林、辽东栎林、混交林和华北落叶松林去除枯枝落叶层后，土壤入渗量比对照平均降低100mm以上;表层土壤含水量分别比对照土壤下降了6.26、18.26、15.06和15.07个百分点。地表径流量分别增加了，辽东栎林34.299mm(603%)和15.816mm(525%);油松林14.593mm(732%)和10.584mm(1321%);混交林12.004mm(181%)和7.275mm(364%);华北落叶松林3.555mm(118%)，3.275mm(229%)。96年生长季，各土壤流失量分别增加了：油松林172.751t/hm~2(124倍);辽东栎林836.500t/hm~2(119倍);混交林172.499t/hm~2(47倍);华北落叶松林11.557t/hm~2(11倍)。表层土壤容重分别增加了：油松林15.0%和20.6%，辽东栎林18.4%和28.2%，混交林11.5%和38.5%，华北落叶松林4.3%和17.1%。 0-60cm深度土壤容重平均值的大小顺序为：草地>灌丛>辽东栎林>油松林>混交林>华北落叶松林;而土壤孔隙度的大小顺序为华北落叶松林>混交林>油松林>辽东栎林>灌丛>草地。两个生长季为土壤实际储水量的均值：油松林，124.45mm，78.62mm;辽东栎林，131.23mm，87.72mm;混交林，180.41mm，113.90mm;华北落叶松林，165.53mm，127.95mm;灌丛，172.50mm，89.81mm;草地，152.92mm，89.59 mm分别比干旱年份97年高出45.83mm、43.51mm、51.63mm、37.58mm、82.69mm和63.33mm。两个生长季的地表径流量为草地，30.930mm(2.79%);灌丛，16.321mm(147%);油松林，2.911mm(0.26%);辽东栎林，8.703mm(0.78%);混交林，8.625mm(0.78%);华北落叶松林，4.447mm(0.40%)。油松林、混交林和华北落叶松林地表径流量与降水量P(mm)和最大雨强(mm/h)正相关显著;而辽东栎林、灌丛和草地的地表径流量则与降水量P(mm)、平均雨强Q(mm/hr)和最大雨强M(mm/hr)三者之间呈显著正相关关系。与草地相比(1220.093kg/hm~2，100％)，灌丛、辽东栎林、混交林、油松林和华北落叶松林96年生长季的土壤流失量分别降低了85.05%、94.26%、96.99%、98.86和99.14%。 降水量是影响小流域径流量时间变化的主要因素;南沟和马牙石沟96年的径流量分别是97年的8.19倍和7.87倍，而径流深(46.25mm，52.75mm)分别比97年(5.65mm,6.70mm)高出40.60mm和46.05mm。两个小流域由于面积的差异而使南沟两年的径流量分别比马牙石沟高出2773.136m~3(13.15%)和235.434m~3(8.79%)。96年和97年马牙石沟径流深比南沟高出6.5mm(14.05%)和1.05mm(18.58%)。在地处大陆性季风气候区的东灵山地区，用0.010m~3/min/km~2/hr能较好地分割小流域的洪峰和基流。在五次暴雨水文曲线中，马牙石沟的快速径流量分别比南沟高出25.00%到143.33%。五次洪水水文响应R的平均值南沟为0.218%，马牙石沟为0.404%;与海洋性气候地区相比，东灵山地区小流域的R值要低一到两个数量级。马牙石沟洪峰流量Qp的平均值为418.772L/min要比南沟(281.191L/min)大48.9%。东灵山地区小流域的洪水径流过程可分为三种类型。

克隆植物绢毛匍匐委陵菜的生态对策研究

本文以匍匐茎草本绢毛匍匐委陵菜(Potentilla reptans L var. sericophylla)为研究对象，基于实验生态学研究方法和野外调查研究了该植物对异质性环境的生态适应对策。 　　对落叶松和油松群林下的绢毛匍匐委陵菜的基株特征和种群特征研究表明：在落叶松林下，绢毛匍匐委陵菜克隆分株具有更大叶面积和更长叶柄;在油松林下，绢毛匍匐委陵菜具有更多的匍匐茎和更多的克隆分株。两个生境中的绢毛匍匐委陵菜形成与其生境相适应的克隆形态和克隆生长特征。在两个群落中的绢毛匍匐委陵菜分株种群的密度和地上生物量没有差异。 　　应用GS+统计软件分析了绢毛匍匐委陵菜分株种群特征及其与所处的土壤基质九个指标（土壤有机质（SOC）、土壤全氮（STN）、土壤全磷（STP）、有效钾（K+）、有效磷（PO43-）、NH4+、NO3-、土壤含水量（SWC）、pH）的空间分布格局的关系，结果显示，绢毛匍匐委陵菜克隆分株种群呈斑块状分布，其克隆分株数的空间自相关尺度为1米;其生长的土壤基质的9个土壤养分及土壤性状指标也都显示了强烈的空间自相关，其自相关尺度（变程）范围在0.24 m ～1.05 m之间，大小顺序为STP>K+>SOC>pH>STN> NO3-> PO43->SWC> NH4+。 其中除STP外，其他8个土壤指标的空间自相关尺度都在0.5 m 左右，NH4+仅为24.4 cm。绢毛匍匐委陵菜野外克隆分株的匍匐茎节间长平均在7 cm 左右。由此表明绢毛匍匐委陵菜克隆分株种群的空间分布尺度大于其所在土壤基质养分及其物理性状的分布尺度，相互联结的克隆分株对异质性土壤资源表现出较大的缓冲能力。其原因之一有可能是克隆生理整合作用使克隆分株局部反应减弱，克隆分株表现趋于一致，克隆分株间实现资源共享，从而高效利用异质性土壤资源。 　　绢毛对匍匐委陵菜克隆特征的局部特化实验将生长在北京东灵山油松（Pinus tabulaeformis）林林窗和林下的绢毛匍匐委陵菜，进行生境间的交互移植-重植野外生态实验以验证绢毛匍匐委陵菜林窗和林下种群间的行为差异是完全由表型可塑性引起，还是局部分化的结果。研究结果表明，实验植物的叶片长度、叶片宽度、叶柄长度和匍匐茎节间长度等克隆形态特征在两生境间无差异。两个来源的植株，其基株生物量、基株分株数和基株匍匐茎总长度等克隆生长特征在林下生境中都比在林窗生境中小，表现出显著的可塑性。所研究的克隆形态特征和克隆生长特征及其可塑性在不同生境来源的实验植物间没有差异。绢毛匍匐委陵菜克隆形态特征和克隆生长特征及其可塑性在林下和林窗生境间没有发生局部分化，林窗为其较适生境，克隆生长特征的可塑性对绢毛匍匐委陵菜利用生境异质性可能具有主要意义。 　　绢毛匍匐委陵菜对土壤养分的克隆可塑性共进行了两个实验。实验1 探讨绢毛匍匐委陵菜对8个土壤基质养分梯度(N, P, K)的克隆可塑性。其结果表明，在植株能够生长的土壤基质养分条件下，随着土壤养分浓度增加，基株生物量、匍匐茎数、分株数增加;生物量分配可塑性反应格局为：随着土壤基质养分浓度的增加，对根生物量投资降低，对叶片的生物量投资增加，而对匍匐茎的投资没有改变。匍匐茎节间长、比叶片重没有对土壤养分梯度发生可塑性反应。随着土壤基质养分的增加，植株根冠比和比根重下降，而根系总长和叶片面积增加。实验2 设置与实验1相同的8个土壤养分梯度，分三个时期收获以探讨绢毛匍匐委陵菜不同发育时期对土壤养分梯度的克隆可塑性，其结果表明：随着植株发育年龄的增加，绢毛匍匐委陵菜的克隆可塑性有增强的趋势。生物量分配格局对土壤养分梯度的可塑性反应早于基株总生物量的可塑性反应;叶片面积、根系总长度和比根重在植物生长后期对土壤养分梯度发生可塑性反应;比叶面积在植物生长早期对土壤养分梯度发生可塑性反应，而在后期则没有;匍匐茎比节间重在生长之初和生长后期均对养分梯度发生可塑性反应。 　　绢毛匍匐委陵菜对局部遮荫的克隆可塑性实验是将采自林窗和林内生境的绢毛匍匐委陵菜“分株对”（即由一匍匐茎节间相连着的两个分株，其一为“目标分株”另一为“相连分株”）在一户外实验中进行全不遮荫、全部遮荫和局部遮荫处理。其结果表明，绢毛匍匐委陵菜基株生物量、匍匐茎总长度、分株数、匍匐茎比节间重、叶柄长、比叶柄重在遮荫条件下较小。匍匐茎节间长度没有对遮荫处理发生反应。在局部遮荫处理，遮荫斑块的分株的叶柄长度由于连着未遮荫斑块中分株而变得更长。这种克隆整合对克隆形态可塑性的修饰作用只在林窗生境来源的实验植物中观察到。其它克隆生长和克隆形态特征的可塑性在不同生境来源的实验植物间没有差异。

Variety of antimicrobial peptides in the Bombina maxima toad and evidence of their rapid diversification

Antimicrobial peptides secreted by the skin of many amphibians play an important role in innate immunity. From two skin cDNA libraries of two individuals of the Chinese red belly toad (Bombina maxima), we identified 56 different antimicrobial peptide cDNA sequences, each of which encodes a precursor peptide that can give rise to two kinds of antimicrobial peptides, maximin and maximin H. Among these cDNA, we found that the mean number of nucleotide substitution per non-synonymous site in both the maximin and maximin H domains significantly exceed the mean number of nucleotide substitution per synonymous site, whereas the same pattern was not observed in other structural regions, such as the signal and propiece peptide regions, suggesting that these antimicrobial peptide genes have been experiencing rapid diversification driven by Darwinian selection. We cloned and sequenced seven genes amplified from skin or liver genomic DNA. These genes have three exons and share the same gene structure, in which both maximin and maximin H are encoded by the third exon. This suggests that alternative splicing and somatic recombination are less likely to play a role in creating the diversity of maximins and maximin Hs. The gene trees based on different domain regions revealed that domain shuffling or gene conversion among these genes might have happened frequently.

Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

We transplanted kidneys from alpha 1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GaIT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GaIT-KO pigs to humans.

近代鸟类分类与系统发育研究进展

简要综述了宏观和微观领域的鸟类分类学研究进展。宏观领域介绍了传统形态分类学、数值分类学和支序 分类学, 结合鸣声分析强调支序分类学的应用。微观领域介绍了Sibley 分类系统和近年来出现的主要基于mtDNA 的鸟类系统学研究。通过对大量研究工作的分析提出该领域今后应进行综合性研究。

与精子功能相关抗原的分析

与精子功能相关抗原的分析贲昆龙（中国科学院昆明动物研究所，昆明，６５０２２３）精子的发生和形成始于睾丸的精小管，在精小管内，用原细胞逐渐分化成精母细胞、精细胞和精子。这个过程是在哺乳动物和人的免疫系统成熟之后发生的，是在由支持细胞形成的血睾屏障的严密...

Robust estimation of local genetic ancestry in admixed populations using a nonparametric Bayesian approach.

We present a new haplotype-based approach for inferring local genetic ancestry of individuals in an admixed population. Most existing approaches for local ancestry estimation ignore the latent genetic relatedness between ancestral populations and treat them as independent. In this article, we exploit such information by building an inheritance model that describes both the ancestral populations and the admixed population jointly in a unified framework. Based on an assumption that the common hypothetical founder haplotypes give rise to both the ancestral and the admixed population haplotypes, we employ an infinite hidden Markov model to characterize each ancestral population and further extend it to generate the admixed population. Through an effective utilization of the population structural information under a principled nonparametric Bayesian framework, the resulting model is significantly less sensitive to the choice and the amount of training data for ancestral populations than state-of-the-art algorithms. We also improve the robustness under deviation from common modeling assumptions by incorporating population-specific scale parameters that allow variable recombination rates in different populations. Our method is applicable to an admixed population from an arbitrary number of ancestral populations and also performs competitively in terms of spurious ancestry proportions under a general multiway admixture assumption. We validate the proposed method by simulation under various admixing scenarios and present empirical analysis results from a worldwide-distributed dataset from the Human Genome Diversity Project.

溶藻细菌DC21的分离、鉴定及其溶藻特性

从云南滇池中分离得到一株溶藻细菌DC21,经鉴定为葡萄球菌属的1种(Staphylococcussp.),可溶解铜绿微囊等9种藻.试验表明,经过滤、离心沉降及高温灭菌处理的滤液,均能强烈抑制铜绿微囊藻的生长,说明其溶藻作用的因子之一为该菌的胞外分泌物,且这种物质具有热稳定性.细菌DC21使藻的光合作用受到抑制;在试验的第1d,受试藻的超氧物歧化酶及过氧化氢酶活性显著增高,但在第7d,这两种抗氧化保护酶的活性显著下降;受试藻的丙二醛含量明显增高,说明该菌促使其发生了膜脂过氧化.

Distributed flow algorithms for scalable similarity visualization

We describe simple yet scalable and distributed algorithms for solving the maximum flow problem and its minimum cost flow variant, motivated by problems of interest in objects similarity visualization. We formulate the fundamental problem as a convex-concave saddle point problem. We then show that this problem can be efficiently solved by a first order method or by exploiting faster quasi-Newton steps. Our proposed approach costs at most O(|ε|) per iteration for a graph with |ε| edges. Further, the number of required iterations can be shown to be independent of number of edges for the first order approximation method. We present experimental results in two applications: mosaic generation and color similarity based image layouting. © 2010 IEEE.

High variability of the gvpA-gvpC region in Microcystis

Gas vesicles provide buoyancy to Microcystis and other common cyanobacterial bloom-forming species. gvpA and gvpC are structural genes encoding gas vesicle proteins. Phylogenetic analyses of 10 Microcystis strains/uncultured samples showed that gvpC and each intergenic segment of the gvpA-gvpC region can be divided into two types. The combination of different types of gvpC and intergenic segments is an important factor that diversifies this genomic region. Some Microcystis strains isolated in China possess a 172 to 176 bp sequence tag in the intergenic segment between gvpA and gvpC. The gvpA-gvpC region in Microcystis can be divided into at least 4 classes and more numbers of subclasses. Compared to rbcLX and other regions, the high variability of the gvpA-gvpC region should be more useful in identifying geographical isolates or ecotypes of Microcystis.