榕小蜂的产卵模式及其对子代性比的影响

于2007年4月—2007年7月在中国科学院西双版纳热带植物园,通过干预控制榕小蜂产卵的方法研究了聚果榕的传粉榕小蜂Ceratosolen fusciceps和非传粉小蜂Platyneura mayri及垂叶榕的非传粉小蜂Acophila sp.1和Wakerella benjamini等的产卵顺序。对传粉榕小蜂,在完成放蜂后不同间隔时间向榕果内注入乙醚杀死小蜂;对非传粉榕小蜂,在放蜂后不同间隔时间将其从纱网袋内全部放出,从而控制了各种榕小蜂的产卵时间。到榕果成熟后,收集了榕果内的小蜂,并分析比较各种榕小蜂在不同产卵时间下的子代性比。结果表明：Ceratosolen fusciceps、P. mayri和Acophila sp.1在产卵的最初时间内倾向于产下更多的雄性后代,而随后的时间内则产下更多的雌性伴随少量的雄性后代,这样的产卵顺序导致子代性比随着母代产卵时间的延长而下降,榕小蜂后代雌性比例显著高于雄性。同时,子代榕小蜂数量随母代产卵时间的延长而增加,这在一定程度上解释了单头繁殖雌蜂的子代性比随子代数量的增加而减少的现象。而Wakerella benjamini在产卵顺序上是随机的,在其开始产卵后的不同时间段内子代性比都接近于50%。这一结果表明榕小蜂的产卵顺序与母代产卵时间的长短对子代性比有极为重要的影响。     

笔管榕榕小蜂的群落结构与物种多样性

笔管榕为桑科榕属落叶乔木,雌雄同株,为福建地区的常见树种。笔管榕榕果内生活着多种榕小蜂,它们与笔管榕共同构成了榕树-榕小蜂共生体系。通过全年(2011年7月至2012年7月间)对福州地区不同样地的30株笔管榕进行的定时、定点、定株观察与采集,在15批次830个榕果中,共收集到50817头榕小蜂。笔管榕榕果内有7种小蜂,隶属于小蜂总科中的6个科(亚科)7个属,其中榕小蜂科的Platyscapa ishiiana为传粉小蜂,其余6种为非传粉小蜂,分别属于金小蜂科、广肩小蜂科、姬小蜂科及隐针榕小蜂亚科。非传粉小蜂中的Philotrypesis sp.、Acophila mikii、Otitesella ako、Sycophila sp.和Sycobiomorpha sp.小蜂几乎在全年的每个月都可采集到,属常见种。Aprostocetus sp.全年仅收集到2头,为偶见种。笔管榕榕果内的榕小蜂种类在不同月份、不同季节没有明显变化,但不同种类榕小蜂的数量变化明显。在笔管榕榕小蜂群落结构中,全年有9个月均是传粉小蜂占优势,但在1月、9月和11月的采集批次中,非传粉小蜂占优势。非传粉小蜂(Acophila mikii、Sycophila sp.、Philotrypesis sp.和Otitesella ako)常呈爆发性发生,每批次中往往是1-2种的非传粉小蜂数量较多,但不同批次,数量较多的非传粉小蜂种类往往不同,因此在小蜂群落结构中未见某种非传粉小蜂占明显优势。福州地区笔管榕榕果内小蜂群落的的多样性指数为0.72,均匀度指数为0.37,丰富度指数为0.55,优势集中性指数为0.68。分析了6种小蜂的性比,结果表明:传粉小蜂的性比极度偏雌,非传粉小蜂虽然也偏性,但均高于传粉小蜂,推测榕小蜂性比与雄蜂的翅型和交配场所有关。非传粉小蜂的数量和传粉小蜂总数、雌蜂数和雄蜂数均呈极显著负相关,和性比呈极显著正相关关系,说明非传粉小蜂对传粉小蜂的雌、雄蜂都有负面影响,且传粉小蜂雌蜂减少的幅度大于传粉小蜂雄蜂,从而导致其性比升高。非传粉小蜂中Acophila mikii、Sycobiomorpha sp.、Otitesella ako Ishii为造瘿类群,Philotrypesis sp.、Sycophila sp.属于寄居者或寄生者类群,非传粉小蜂中的寄生或寄居类群与造瘿类群相比,对传粉小蜂的负面影响更大。研究结果为榕-蜂协同进化研究,以及城市绿化和生物多样性保护提供科学依据。     

垂叶榕上16种榕小蜂的种群动态

传粉榕小蜂和榕树的互利共生是传粉昆虫与植物间协同进化的典范。在榕果(榕树的隐头状花序)内,还生活着多种非传粉榕小蜂。这些生活在密闭榕果内由传粉榕小蜂和非传粉榕小蜂组成的群落对研究群落生态学有很大价值。然而,对生存在单一榕树的榕果内的所有榕小蜂的种群动态了解很少,特别是缺少相对长期的连续数据。通过野外近3a观察和采样,研究了垂叶榕榕小蜂群落结构和榕小蜂的种群动态。共记录榕小蜂16种;各种榕小蜂根据发生规律可分为常见种和偶见种,Eupristina koningsbergeri,Philotrypesis sp.1,Philotrypesis sp.4,Philotrypesis sp.5,Sycoscapter sp.1,Walkerella benjamini,Walkerella sp.1,Sycophila sp.2,Sycobia sp.2为常见种;Sycobia sp.1,Acophila sp.1,Sycophila sp.1,Ormyrus sp.1等为偶见种。每种榕小蜂在单果上的数量随季节呈波动变化,季节对榕小蜂群落的多样性和均匀性无显著影响。除了传粉榕小蜂外,Sycoscapter sp.1也是优势种类之一。传粉榕小蜂的数量与非传粉榕小蜂总数间呈显著负相关。传粉榕小蜂与非传粉榕小蜂几乎都呈负相关,而与Walkerella sp.1在数量上呈显著正相关。Sycobia sp.2与Sycophila sp.2在同一瘿中出现,数量上呈显著正相关。但其它非传粉榕小蜂种类在数量上的相关性较为复杂,可能是造成各种榕小蜂数量波动的一个原因。     

环纹榕传粉榕小蜂的传粉模式

榕小蜂的传粉结构、 传粉行为以及寄主榕树的花药胚珠比是判断榕-蜂互惠系统传粉模式的重要依据。本研究于2010年8月至2011年6月对位于云南西双版纳地区的试验样树环纹榕Ficus annulata进行观察, 对出榕果的环纹榕传粉榕小蜂Deilagaon annulatae进行电镜扫描和室内显微镜下对其进行行为观察。电镜扫描显示： 环纹榕传粉榕小蜂D. annulatae位于胸部的花粉筐消失, 具一片可粘附花粉的毛区, 提示其属于被动传粉的种类。传粉行为观察发现, 该蜂没有主动采集花粉的行为, 显然存在的花粉刷已丧失了主动收集花粉的功能。寄主植物环纹榕F. annulata属于典型的自动散粉让榕小蜂沾附花粉的榕树种类。环纹榕传粉榕小蜂D. annulatae是西双版纳热带地区已知58种传粉榕小蜂中唯一体色为黄色的种类, 该蜂偏爱在低温的夜晚出蜂。除了传粉榕小蜂, 一种金小蜂Lipothymus sp.也在雌花期进入榕果内繁殖, 并且其数量显著高于环纹榕传粉榕小蜂D. annulatae (P<0.0001)。自然单果的繁殖中, 环纹榕传粉榕小蜂的数量显著高于种子数量, 呈现出榕-蜂互惠系统中罕见的传粉榕小蜂主导的局面。综合榕-蜂的传粉特征显示, 环纹榕F. annulata及其传粉榕小蜂D. annulatae互惠系统是被动传粉的模式。     

榕果挥发物对传粉榕小蜂的吸引作用

榕树 /榕小蜂专一性共生系统的维持 ,与榕树开花期释放的特殊的挥发性化合物以及榕小蜂对其寄主榕树的化学识别和定位紧密相关。研究选取了西双版纳地区常见的 3种榕树 ,即对叶榕 Ficus hispida、木瓜榕 F.auriculata和鸡嗉子榕F.semicordata的榕果作为实验材料 ,利用野外诱捕实验、室内生物检测实验检测传粉榕小蜂 Hymenoptera:ChalcidoidaeAgaonidae对 12种信息化合物及榕果的二氯甲烷浸提物的趋向性反应 ,研究不同榕属植物的传粉榕小蜂对相同的信息化合物的反应差异 ,以及传粉榕小蜂受不同发育时期榕果浸提物吸引的显著性程度。诱捕实验中对叶榕小蜂 Ceratosolen solmsimarchali对香叶醇的趋向性反应显著 ,大果榕小蜂 C.emarginatus对接受期榕果浸提物和芳樟醇都有明显的趋向性反应 ,而对间花期榕果浸提物则无显著反应。嗅觉仪生物检测实验中 ,鸡嗉果榕小蜂 C.gravelyi对香叶醇和松油醇都表现出显著的趋向性反应。结果表明 ,对叶榕、鸡嗉子榕传粉榕小蜂对 12种信息化合物的反应存在一定的差异 ,木瓜榕传粉榕小蜂对香叶醇和木瓜榕接受期榕果浸提物的趋向性反应比间花期榕果强得多     

榕树传粉昆虫榕小蜂染色体制备方法研究

榕树与其传粉昆虫榕小蜂之间具有高度专一的互惠共生关系,榕小蜂为榕树传粉的同时又在榕果内营寄生生活,直至完成其整个生活史,因此一直以来对榕小蜂的染色体研究存在很大困难。本文以对叶榕Ficus hispida传粉榕小蜂Ceratosolen solmsi和鸡嗉子榕F.semicordata传粉榕小蜂C.gravelyi为材料,摸索出一套适合于榕树传粉昆虫榕小蜂染色体研究的详细、有效的技术和方法。应用该法对对叶榕传粉榕小蜂C.solmsi和鸡嗉子榕传粉榕小蜂C.gravelyi的染色体核型进行了研究,结果表明两种榕小蜂的染色体核型特征非常相似,具有相同的染色体数目2n(♀)=10,染色体类型全部为中着丝粒染色体,臂数NF=20。此外,在相对长度方面两者也没有明显的差异。最后与Imai等1988年研究蚂蚁染色体时提出的方法进行了比较。利用本文介绍的方法进行榕小蜂染色体制备,操作过程简单、重复性强,不仅能够得到大量的染色体分裂相,而且染色体细胞界限明确、形态清晰、分散良好。     

榕长尾小蜂属(小蜂总科,金小蜂科)研究和二新纪录种

记述金小蜂科榕长尾小蜂属Sycoscapter中国2新纪录种,Sycoscapter cornutus Wiebes,1981和S.keralensis（Abdurahi man＆Joseph）,1975。分别从采自海南儋州和陵水的小叶榕Ficus microcarpa L.榕果中育出。小叶榕为寄主新纪录。研究标本保存在中国科学院动物研究所动物标本馆。     

两种雌雄同株榕树榕果内小蜂空间分布格局

在雌雄同株榕树榕果内,除传粉榕小蜂外,还寄生着很多种类的非传粉榕小蜂。为弄清传粉和非传粉榕小蜂在榕果内的空间分布格局,以西双版纳地区的垂叶榕和高榕及与之相关的传粉和非传粉榕小蜂为研究材料,比较了不同种类小蜂所在瘿花花梗长度差异。结果表明:(1)在高榕中,Eupristinasp.所在瘿花花梗平均长度最长,传粉榕小蜂Eupristina altissima所在瘿花花梗长度次之。Micranisa ralianga、Sycobiasp.和Sycoscaptersp.2所在瘿花花梗长度无显著差异。Sycobiasp.、M.ralianga以及Sycoscaptersp.2所在瘿花花梗长度范围要窄于传粉榕小蜂所在瘿花花梗长度范围。这都说明这三种果外产卵非传粉榕小蜂与传粉榕在空间生态位上存在部分的分离。(2)在垂叶榕中,Eupristina koningsbergeri可以分布在从最外层到内层的瘿花,而大多数Walkerellasp.都集中在靠近果壁的瘿花内,表明两者也存在部分空间生态位的分离。     

鸡嗉子榕小蜂繁殖资源的空间结构与食性关系

榕蜂繁殖共生体是榕小蜂与榕树因营养级联而形成的多功能群落,被认为是定量研究群落组装与驱动机制的优良模型.本文以鸡嗉子榕Ficus semicordata Buchanan-Hamilton ex Smith果内寄生的5种榕小蜂及其繁殖资源为研究对象,综合应用路径分析和混合线性模型,构建营养级联关系,解析不同功能类群间的瘿花资源占用和生态位分化,以探讨物种食性及其互作关系.结果发现:单果内寄生的鸡嗉子榕小蜂一般有3种或4种,占比分别为37.06％或35.53％,以传粉者窝榕小蜂 Ceratosolen gravelyi Grandi、寄生者伪鞘榕小蜂 Sycoscapter trifemmensis Joseph和寄居者拉长鞘榕小蜂Sycophaga cunia Joseph最为常见,每种榕小蜂的种群数量也存在巨大差异.寄居者妃延腹榕小蜂Philotrypesis dunia Joseph和拉长鞘榕小蜂、寄生者伪鞘榕小蜂直接作用于窝榕小蜂,寄生者缩腹榕小蜂Aprocrypta sp.则寄生于妃延腹榕小蜂,而拉长鞘榕小蜂与妃延腹榕小蜂之间有负相关关系.不同榕小蜂所占用的瘿花具有明显的空间层次性,其中传粉者窝榕小蜂位于最外层,而非传粉榕小蜂则位于中下层,每种雄蜂均比同种雌蜂更靠近外层,但每种榕小蜂及其雌雄两性繁殖瘿花的大小均没有差异,表明造瘿者、寄居者和寄生者所组成的功能类群,在一定程度上反映了榕小蜂在寄生与生态位方面存在进化约束.研究结果将有助于理解鸡嗉子榕小蜂群落组成的生态驱动机制.     

非传粉小蜂对榕-蜂共生系统的影响

榕-蜂共生系统是桑科榕属(Ficus)植物与传粉榕小蜂专一互惠形成的生态学关系。但是,也有一些非传粉的小蜂出现在这个系统中,对榕-蜂共生系统可能产生较大的影响。西双版纳的聚果榕(Ficus racemosa)树上主要有5种非传粉小蜂,分别在榕果发育的不同阶段从果外向果内产卵。在传粉榕小蜂进果之前的花前期,Platyneura testace、Apocrypta sp.和P. mayri这3种非传粉小蜂先后到果外产卵繁殖后代,对榕-蜂共生系统造成显著影响,尤其是影响传粉榕小蜂的繁殖。在传粉榕小蜂进果之后的间花期,P. mayri、A. westwoodi和P. agraensis这3种非传粉小蜂相继到果外产卵,它们虽然能减少种子形成和传粉榕小蜂繁殖的数量,但最终没有对榕-蜂共生系统造成显著的影响。造瘿类的P. mayri可在花前期和间花期产卵繁殖,在花前期产卵时它主要是影响传粉榕小蜂的繁殖,而在间花期产卵时它则更多地是影响种子的生产。     

基于芽苗砧嫁接油茶砧穗创伤后内源激素动态变化分析

为研究油茶(Camellia oleifera A)嫁接时穗条和砧木创伤后内源激素动态变化规律,解析影响砧穗嫁接面愈合的生理机制,为油茶砧穗愈合生长机理提供理论支持。以树龄6年的长林18号和53号的穗条和实生砧木为材料,按照芽苗砧嫁接方法切割穗条S0(0 min)、S10(10 min)、S40(40 min)和砧木茎段Z0(0 min)、Z10(10 min)后,利用液质联用法(HPLC-MS)测定吲哚乙酸(IAA)、脱落酸(ABA)、反式玉米素(TZR)、玉米素(Zeatin)、水杨酸(SA)和茉莉酸(JA)含量,分析不同时间段内源激素变化及品种间差异的关系。结果显示:创伤后18号的TZR、Zeatin和SA含量总体高于53号;18号IAA、SA和JA逐渐下降;TZR和Zeatin分别在S10和S0达最高值后下降;ABA在S10达最高值。53号IAA和JA爱S10达最高值后下降;TZR、Zeatin和SA在S10达低值后逐渐上升;ABA在S0达高值后逐渐下降。砧木茎段创伤前后激素含量除JA外18号高于53号;两品种Z0时激素含量下降,Z10后上升,仅53号ABA和SA含量在Z0达高值后下降。砧木茎段和根部激素含量在品种间除JA外18号高于53号,茎段的IAA、ABA高于根部,其他激素为根部高于茎段。激素比值在品种间和部位间差异明显;IAA/ABA、IAA/TZR、IAA/Zeatin和IAA/JA、ABA/TZR、ABA/Zeatin和ABA/JA比值为53号高于18号;穗条内SA/IAA为18号高于53号,SA/JA和SA/ABA为53号高于18号;砧木茎段均为18号高于53号;TZR/SA、TZR/JA比值在穗条和砧木茎段为18号高于53号。两品种创伤后IAA与JA极显著正相关,而IAA与SA,SA与JA在18号极显著正相关,53号极显著或显著负相关;53号TZR、Zeatin、SA间极显著或显著正相关,JA与TZR、Zeatin和SA极显著负相关。砧木茎段创伤后18号激素间为极显著或显著正相关;53号TZR和Zeatin与IAA、JA极显著正相关,与SA存在显著负相关,SA与JA有显著负相关。砧木茎段和根部间品种间仅在SA与各激素间相关性存在差异,其他激素间存在极显著正相关或负相关。综上所述,砧穗创伤后激素水平上18号在创伤面易于愈伤组织发育,而53号抗逆激素水平较高且与细胞分裂增殖类激素负相关,可能影响53号嫁接后愈合生长;嫁接应在创伤后10 min内较为适宜;砧穗间激素含量及比值的差异可能会影响后期嫁接部位形态重建以及穗条生长。     

社鼠组织器官同工酶的研究

用聚丙烯酰胺凝胶等电聚焦电泳方法,分析了社鼠的肝、肾、心肌、骨骼肌、肺、脾和脑等多种组织器官的ＬＤＨ、ＡＤＨ、ＥＳＴ、和ＳＯＤ４种同工酶,对各组织器官的酶带数目和分布,以及酶活性进行了比较研究。结果表明,社鼠的ＬＤＨ同工酶、ＡＤＨ同工酶和ＥＳＴ同工酶具有比较明显的组织特异性,而ＳＯＤ同工酶的组织特异性较低。肺和脾除ＥＳＴ同工酶活性较高外,脑除ＬＤＨ同工酶活性较高外,其它３种同工酶的活性均较低;而肝和肾中４种同工酶的活性普遍很高。心肌和骨骼肌因氧张力不同而使ＬＤＨ同工酶酶谱存在明显差异,但其它３种同工酶酶谱却非常相似。同工酶的组织特异性与各组织器官所执行的生理功能是相一致的     

洪湖野菰及其化学成分分析

野菰(Zizania latifolia)是湖北省洪湖中优势水生维管束植物,其群落占全湖355平方公里面积的127平方公里。茎和叶的年生物量为4379克鲜重/平方米,全湖总年产量121700吨干重,目前未被利用。野菰各器官的蛋白质和氨基酸含量分别以百分干重表示:根,7.0和4.76;根状茎,11.3和8.85;茎,9.5和7.15;嫩茎梢,22.4和16.53;叶,16.8和14.61。500克干叶的必需氨基酸含量接近100克干重草鱼幼鱼背肌的必需氨基酸含量。脂肪:叶中3.4～4.2,茎中2.2;粗纤维:叶中26.8～28,茎中24.2;灰分:叶中10.0,茎中5.8。菰茎含可溶性糖类30％以上,其中葡萄糖,果糖、蔗糖和麦芽糖是主要成分。结果表明野菰是一种优质饲料。     

Identification of reciprocally regulated gene modules in regenerating dorsal root ganglion neurons and activated peripheral or central nervous system glia

Differential gene expression in the rat after injury of dorsal root ganglion neurons in vivo, and simulation injury of Schwann cells and oligodendrocytes in vitro was analyzed using high-density cDNA microarrays. The analyses were carried out to study the genetic basis of peripheral nerve regeneration, and to compare gene regulation in glia of the central (oligodendrocyte) and peripheral (Schwann cell) nervous systems. The genes showing significant differential regulation in the three study groups represented all aspects of cellular metabolism. However, two unexpected observations were made. Firstly, a number of identical genes were differentially regulated in activated Schwann cells, activated oligodendrocytes and regenerating DRG neurons. Specifically, a group of 113 out of 210 genes that were down-regulated in Schwann cells upon lipopolysaccharide (LPS) treatment, were identical to genes up-regulated in the injured, regenerating DRG. Furthermore, a group of 53 out of 71 genes that were down-regulated in interferon gamma (IFN-gamma)/LPS-activated oligodendrocytes, were identical to genes up-regulated in the DRG neurons. Finally, 22 genes were common to these three groups, i.e., down-regulated in activated oligodendrocytes, down-regulated in activated Schwann cells, and up-regulated in regenerating DRG neurons. Secondly, a group of 16 cell-cycle and proliferation-related genes were up-regulated in the DRG following sciatic nerve crush, despite the absence of cells undergoing mitosis in the DRG, or any significant presence of apoptosis-related gene expression. Therefore, it appears that in these three cell types, large sets of genes are reciprocally regulated upon injury and/or activation. This suggests that the activation of the injury-related gene expression program in cell derivatives of the neuroectoderm involves, in part, highly conserved genetic elements.     

Seasonal patterns in feeding ecology of three small fishes in the Biandantang Lake, China

Feeding ecology of three small fish species, Hypseleotris swinhonis, Ctenogobius giurinus and Pseudorasbora parva was studied seasonally in the Biandantang Lake, a small, shallow lake in central China. Gut length, adjusted for total body length, was significantly higher in spring than in other seasons for all the three species. Seasonal changes in gut length were not associated with changes in food quality. Weight of fore-gut contents, adjusted for body weight, was significantly higher in winter and spring than in summer and autumn in H. swinhonis and C. giurinus , and significantly higher in autumn than in spring and summer for P. parva. Percentage of empty fore-guts was highest in summer and lowest in spring for H. swinhonis and C. giurinus , and highest in winter and lowest in autumn for P. parva. Diet of the three small fishes showed apparent seasonal changes, and these changes reflected partly the seasonal fluctuations of food resources in environment. Diet breadth was high in winter and low in autumn for H. swinhonis , high in winter and low in spring and summer for C. giurinus , and high in autumn and low in spring for P. parva. Diet overlaps between pairs of species were biologically significant in most cases, except between H. swinhonis and P. parva in summer and autumn and between C. giurinus and P. parva in autumn.     

Dynamics of growth and the content of endogenous phytohormones during kidney bean scoto-and photomorphogenesis

The dynamics of growth and the contents of free and bound endogenous IAA, gibberellins (GA), cytokinins (zeatin and its riboside), and ABA in kidney bean plants (Phaseolus vulgaris L., cv. Belozernaya) grown in darkness or in the light was studied. Phytohormones were quantified in 5–15-day-old plants by the ELISA technique. Plant growth and phytohormone content were shown to depend on plant age and the conditions of illumination. During scotomorphogenesis, changes in the biomass and hypocotyl length were highly correlated with the content of GA, whereas during photomorphogeneses, these parameters were correlated with the content of zeatin. In darkness, epicotyl growth displayed a positive correlation with the content of GA, whereas in the light, the correlation was negative. Growth characteristics of the primary leaves were shown to correlate with IAA in darkness and with GA and zeatin in the light. At a low concentration of cytokinins in illuminated leaves, cell divisions occurred, whereas, at the higher cytokinin concentrations, cell expansion occurred. The highest content of GA was characteristic of leaves in the period of growth cessation. ABA accumulated during active leaf and root elongation and biomass increment in the light and during hypocotyl growth in darkness. After plant illumination, the ratio of auxins to cytokinins increased in bean roots and decreased in their epicotyls. Thus, light changed the developmental programs of bean plants, which was manifested in the changed rate and duration of growth of various organs (root, hypocotyl, epicotyl, and leaf). Some mechanisms of light action depended on the contents of IAA, ABA, GA, and cytokinins and the ratios between these phytohormones. Differences between scotonorphogenesis of mono-and dicotyledonous plants are discussed in relation to the levels of phytohormones in them.     

啮齿动物作用下退耕地山杏种子扩散与贮藏的季节变化

啮齿动物对植物种子的取食和扩散影响种子的时空分布,继而影响种子的萌发和幼苗建成,因而在森林更新中起着重要作用.在国有济源市愚公林场,选择退耕地生境,于春季、夏季、秋季分别释放人工标记的山杏种子,观察啮齿动物扩散与埋藏山杏种子的季节性差异.结果表明：1）退耕地中的啮齿动物主要包括大林姬鼠、社鼠、黑线姬鼠;2）山杏种子扩散速率在春季显著慢于夏季,夏季显著慢于秋季;3）种子搬运量受季节和种子状态交互作用影响,春季显著少于夏季,夏季显著少于秋季;4）不同季节种子平均搬运距离不同,秋季不同状态种子的搬运距离均大于春季和夏季;5）啮齿动物对山杏种子的贮藏点大小多为1粒种子,少量为2、3粒种子,且贮藏点大小与季节间存在显著的交互作用,春季单粒种子的贮藏点数量显著少于夏季和秋季,而夏季与秋季的贮藏点则倾向于多粒种子;6）在夏季和秋季各有5枚（共释放1800枚）被啮齿动物分散贮藏的山杏种子建成幼苗.     

Regulation of the catalytic activity of preexisting tyrosinase in black and Caucasian human melanocyte cell cultures

The activity of tyrosinase, the rate-limiting enzyme for melanin synthesis, is higher in Black skin melanocytes than in melanocytes derived from Caucasian skin. This variation in enzyme activity is not due to differences in tyrosinase abundance or tyrosinase gene activity, but, rather, is due to differences in the catalytic activity of preexisting tyrosinase. In melanocytes, tyrosinase is localized to the membrane of melanosomes and in Caucasian melanocytes the melanosome-bound enzyme is largely inactive. Conversely, in melanosomes of Black melanocytes, tyrosinase has high catalytic activity. Treatment of Caucasian melanocytes with the lysosomotropic compound ammonium chloride or with the ionophores nigericin and monensin results in a rapid and pronounced increase in tyrosinase activity. This increase occurs without any change in tyrosinase abundance, indicating that these compounds are increasing the catalytic activity of preexisting enzyme. Inhibition of the vacuolar proton pump V-ATPase by treatment of Caucasian melanocytes with bafilomycin also increases tyrosinase activity. In contrast to the 10-fold increase in tyrosinase observed in Caucasian melanocytes, neither ammonium chloride, monensin, nigericin, nor bafilomycin is able to increase the already high level of tyrosinase activity present in melanosomes of melanocytes derived from Black skin. Finally, staining of Caucasian melanocytes with the fluorescent weak base acridine orange shows that melanosomes of Caucasian, but not Black, melanocytes are acidic organelles. These data support a model for racial pigmentation that is based on differences in melanosome pH in Black and Caucasian skin types. The models suggests that melanosomes of Caucasian melanocytes are acidic, while those of Black individuals are more neutral. Since tyrosinase is inactive in an acid environment, the enzyme is largely inactive in Caucasian melanosomes but fully active in Black melanosomes.     

安蕨属的分类与分布

1849年,捷克人Presl根据菲律宾产的一种蕨类植物Anisocampium cumingia-num Presl,建立了安蕨属Anisocapium Presl,几十年来未被各国植物学家(如Baker、Beddom、Makino、C.Christensen、Christ、Nakai、秦仁昌、Devol、Ohwi和Tagawa)所承认。1940年,Tard.-Blot et C.Chr.编写《印度支那植物通志》(Fl.Gen.Indo-Chine)时接受了安蕨属的概念。1947年,美国人Copeland研究东南亚蕨类植物时,也肯定了安蕨属是一个自然分类群。以后,     

Differential distribution of leaf chemistry in eucalypt seedlings due to variation in whole-plant nutrient availability

We investigated the effects of whole-plant nutrient-availability on the degree of distribution of some plant primary and secondary (nitrogen, fibre, flavonols, gallotannins and cineole) chemicals across young, mature and old leaves of seedlings of Eucalyptus nitens. Four treatments that ranged from low to high nutrient-application rates resulted in mean whole-plant foliar concentrations of 0.63%, 0.85%, 1.11% and 1.82% nitrogen dry matter (N%DM) for treatments A, B, C and D, respectively. Within-plant distribution (across the leaf age profile of young, mature and old leaves within a eucalypt seedling) of N%DM ranged from zero in treatment A to a wide range of distribution in treatment D (low N%DM concentrations in old leaves to high N%DM concentrations in young leaves). Similarly, the distribution of fibre ranged from zero in treatment A to a wide range of distribution in treatment D, but with high concentrations in old leaves and low concentrations in young leaves. In contrast, flavonols (weakly) and gallotannins had a wide range of distribution in treatment A (low concentrations in old leaves to high concentrations in young leaves) but were little or not distributed in the other treatments. Again in contrast, cineole was strongly distributed between old and young leaves (low concentrations in old leaves to high concentrations in young leaves) across all treatments while concentrations in mature leaves reflected one or other leaf age depending on treatment. Protein precipitable phenols in treatments A, B and C were high in young, and low in old leaves; whereas in treatment D they were low and similar between leaves of different ages.