槭树科植物广义形态学性状分支分析

通过45个广义的形态学性状对槭树科(Aceraceae)尤其是槭属(Acer L.)的主要类群做了分支分析,结果显示：1)槭属内由于各类群分布着较多的同塑性状状态,而难以为属下组间关系的解决提供更多有价值的信息;通过对具体的性状状态分布分析显示,对于象槭属这样在形态上分化较大的类群,由于多数分类性状在不同类群间经历了平行和逆转演化,因而在较低分类阶元水平很难选择合适的性状来通过分支分析构建其系统发育;2)鸡爪槭组(section Palmata)作为整个槭属的基部类群,虽然支持率较低,但与其它类群相比在槭属内维持了较多的原始性状;3)金钱槭属(Dipteronia Oliv.)的两个种作为单系得到了100％的靴带支持,且和槭属作为姐妹群也得到了较好的支持。     

长白山9种槭树的翅果扩散及种子萌发研究

翅果的风媒传播是槭属植物的主要扩散方式之一,且与种子萌发有着密切关联,但具体机理一直还并不明确。以分布于长白山的9种槭树为对象,探讨翅果的形态特征,测定它们在空气中的垂直沉降速度、不同风速下的水平扩散距离以及在扩散距离上的种子萌发率,进而比较并分析翅果的形态性状与沉降速度、水平扩散距离的相关性以及萌发率在不同扩散距离上的差异性。结果表明：(1) 9种槭树的翅果长、宽和面积与沉降速度、水平扩散距离均呈负相关;尽管如此,翅果形态并不是风传播物种的最佳分类指标,而翅载力能较好地反应物种的风传播能力;(2)翅果垂直沉降速度和水平扩散距离间存在显著负相关,表明沉降速度越小,翅果在空气中停留的时间越长,水平方向上扩散距离越远,且强风有助于提高翅果的扩散能力;(3)沉降速度最慢的花楷槭在不同风速下的水平扩散距离均最远,而沉降速度最快的拧筋槭水平扩散距离最短;(4)种子萌发率随扩散距离的增加呈下降趋势。上述结果不仅为深入理解翅果的风力传播机制以及种子萌发对水平扩散距离的响应机制提供科学依据,还可为种群实生更新方面的理论研究提供参考。     

中国特有金钱槭属植物物种分化研究

金钱槭属(Dipteronia Oliv.)隶属于槭树科(Aceraceae),是北温带植物区系中古老、残遗的木本属之一,为中国特有属,属下仅包括金钱槭(D.sinensis Oliv.)和云南金钱槭(D.dyerana Henry)2个物种。本实验从形态学、分子遗传学及基因序列分析等方面对金钱槭(D.sinensis Oliv.)和云南金钱槭(D.dyerana Henry)进行对比研究,探讨其物种间分化程度。结果表明:(1)形态学研究显示两物种形态性状存在显著差异,表明其在形态上发生了显著分化;(2)基因组DNA的AFLP标记分析表明,两物种间存在极显著遗传分化(ΦST=0.390 4),在物种水平及群体水平,两物种遗传多样性及遗传变异水平皆有明显差异(金钱槭云南金钱槭);(3)从GenBank数据库中选出2物种已知的叶绿体基因(psbM-trnD、trnD-trnT、trnL、trnL-trnF、rpl16)和核基因ITS(ITS1、5.8SRNA、ITS2)进行序列进化比对分析,t-test检验表明,2物种叶绿体基因序列间有极显著差异。研究结果表明:金钱槭和云南金钱槭两物种间产生了极显著的分化,推测可能由于长期的地理隔离所致。     

金钱槭和云南金钱槭遗传多样性比较研究

金钱槭属(Dipteronia)是我国特有少种属,属下仅金钱槭(D. sinensis)和云南金钱槭(D. dyeriana)两种。该文用RAPD标记揭示了金钱槭的遗传多样性和遗传结构,并与云南金钱槭的RAPD研究结果进行了比较。同时,对两物种遗传距离与地理距离的相关性进行了分析,结果有助于阐释该属植物遗传变异的产生机制。研究显示,18条随机引物在17个金钱槭居群(226个个体)中检测到128个扩增位点,物种水平的多态位点比率为92.97%,在4个云南金钱槭居群(45个个体)中则检测到103个扩增位点,物种水平的多态位点比率为81.55%,金钱槭的多态位点比率高于云南金钱槭。相似性系数值、Shannon多样性指数和Nei基因多样性指数分析反映了与多态位点比率相一致的结果。AMOVA(Analysis of molecular variance)分析结果显示,金钱槭居群内、居群间的遗传变异分别占总变异量的56.89%和43.11%。云南金钱槭居群内、居群间的遗传变异分别占总变异量的57.86 %和42.14%。Shannon多样性指数、Nei基因多样性指数的分析结果与AMOVA分析结果趋势相同。上述特征值揭示,金钱槭和云南金钱槭居群间的遗传分化均已达到较高水平,推测居群间低水平的基因流可能是导致上述现象产生的原因之一。遗传距离与地理距离的相关分析结果显示,金钱槭居群间的遗传距离与经度差异存在极显著水平的相关性(p<0.01),云南金钱槭居群间的遗传距离与地理隔离则无显著相关关系。说明在大尺度上遗传距离与地理距离相关而在小范围内则无上述关系,该结果可能与位于不同分布区内的物种所承受的生境选择压力不同有关。建议在对该属植物进行就地保护时,应设立多个保护点,保护自然居群及其周围生境;在迁地保护时,应通过加大居群间种子和幼苗的交换,人为创造基因交流和重组的条件,保存该属植物的遗传多样性。     

基于分形方法探讨槭属（Acer Linn.）植物叶片的形态多样性及其系统学意义

采用数量性状测量法分析了槭属(Acer Linn.)8种1变种1变型的叶片形态性状差异,并采用分形方法对供试种类局部叶脉和叶片轮廓进行分维值计算;在此基础上,对供试槭属植物叶片的形态多样性进行比较,并讨论了分形理论在叶片形态特征的定量分析及植物系统学研究中的意义。叶片数量性状的测量结果表明：供试种类叶片的矩形度和叶形系数呈显著正相关,纵横轴比与一级脉角呈显著负相关,这些叶片形态参数的变异程度与叶片的形态多样性有关,虽然能在一定程度上反映槭属植物的叶形及叶脉结构变化,但难以充分反映叶片的变异细节及本质特征。分维值的计算结果表明：供试种类的叶片轮廓和局部叶脉的分维值呈显著负相关;叶片轮廓分维值在种间及种内均有显著差异(P<0.05),但部分种类间局部叶脉分维值差异不显著(P>0.05);鸡爪槭(A. palmatum Thunb.)的叶片轮廓和局部叶脉的分维值变异系数显著高于其他供试种类,表明其种内叶片变异的多样性相对较高。根据叶片轮廓和局部叶脉的分维值,可将供试种类分为4类：鸡爪槭、红枫〔A. palmatum f. atropurpureum ( Van Houtte) Schwerim〕和羽裂槭〔A. palmatum var. dissectum ( Thunb.) Miq.〕归为一类,锐角槭( A. acutum W. P. Fang)、色木槭( A. mono Maxim.)、茶条槭( A. ginnala Maxim.)、三角槭( A. buergerianum Miq.)和中华槭( A. sinense Pax)归为一类,建始槭( A. henryi Pax)和樟叶槭( A. cinnamomifolium Hayata)各自归为一类。研究结果揭示：通过叶缘和叶脉的分形分析可以定量反映植物叶片的形态多样性,建议将叶片轮廓分维值和局部叶脉分维值分别作为种水平和属水平的分类依据;此外,分形方法也为定量化研究和评价不同叶片类型的演化程度提供了可行的途径。     

细裂槭与其近缘种的比较形态学及分类学研究

通过对细裂槭与其近缘种大叶细裂槭、疏毛槭的表型性状及叶片微形态进行比较研究,探讨细裂槭在植物分类学上的地位。结果表明:(1)不同产地细裂槭表型性状变异主要来源于居群内。(2)同一产地细裂槭与其近缘种的一些表型性状存在较大的差异。(3)反映叶片大小和翅果形状指标的平均变异系数相对较大,不能准确反映种间关系,故不支持《中国植物志》、Flora of China以及各类地方植物志中以叶片大小和双翅连接角度作为细裂槭、大叶细裂槭和疏毛槭的主要分类依据。(4)疏毛槭叶上表皮和下表皮均具表皮毛,且生活周期内不脱落,与《中国植物志》和Flora of China对疏毛槭的记载略有不同。依据许炳强提出的植物叶脉序演化关系,细裂槭与大叶细裂槭的叶脉序特征基本一致,而疏毛槭较细裂槭和大叶细裂槭原始,该研究结果支持Flora of China对细裂槭和大叶细裂槭的合并处理,并将细裂槭作为疏毛槭的变种处理。     

基于ITS与 trn L-F序列探讨槭树科的系统发育

报道了槭树科41种(其中槭属39种)植物的 trn L-F和ITS序列(其中部分种的ITS序列为重新测定),以期通过分子手段对槭树科内部尤其是复杂的槭属的系统发育关系进行重建.以无患子科和七叶树科为外类群,基于对57个种单独的ITS序列(包括从GenBank下载的16种的序列)、41种 trn L-F序列及41种两者序列的联合数据,分别采用最大简约法(Maximum Parsimony Method)和邻接法(Neighbor-Joining Method)对槭树科的系统发育进行了分析.结果显示,整个槭树科为一单系类群;金钱槭位于槭树科的基部;但由于云南金钱槭( Dipteronia dyerana )聚在了槭属内部,认为金钱槭属和槭属均可能是非单系类群;槭属内组间关系的支持率普遍较低,但多数组的组内关系得到了较好的支持.将两个片段结合比单独的ITS或 trn L-F分析能更好地解决槭属内部的系统关系,其中sect.Palmata 和sect.Microcarpa ,sect.Platanoidea 、sect.Lithocarpa 和sect.Macrophylla ,sect.Integrifolia 、sect.Trifoliata 和sect.Pentaphylla ,以及sect.Acer 、sect.Goniocarpa 和sect.Saccharina (sensu Ogata)的组间亲缘关系得到了一定的支持,但对其中部分组的划分可能应做进一步调整.重新评价了徐廷志系统中对sect.Rubra 和sect.Saccharodendron 的处理.     

茶条槭自然种群种子和果实表型多样性研究

为探析茶条槭(Acer ginnala)种子和果实表型差异程度及变异规律,该研究采用巢式方差分析、主成分分析、聚类分析等方法,对茶条槭主要分布区内7个种群种子和果实的12个表型性状进行比较研究,分析茶条槭种群间和种群内的表型多样性以及与地理生态因子的关系。结果表明:除种子长/宽(SLW)外,其它11个表型性状在茶条槭种群间和种群内均具有显著差异;各性状平均变异系数(CV)为13.90%,变异幅度为8.14%～32.08%;种群间翅果性状的平均变异系数(15.63%)高于种子性状的平均变异系数(8.71%),表明种子性状的稳定性高于果实性状。主成份分析中,果实形态特征对茶条槭种群表型的贡献率大于种子贡献率。种群间表型分化系数为35.47%,说明种群内变异(64.53%)大于种群间变异(35.47%),暗示变异主要来源于种群内变异。茶条槭种子和果实表型性状受地理生态因子影响较小,主要受自身遗传因素的影响。基于种群间欧式距离的聚类分析将茶条槭7个种群分为2大支,没有严格按照地理距离而聚类,表明茶条槭种群表型性状变异的不连续性。茶条槭不同种群种子和果实具有较高的表型多样性,与其分布范围和生物学特性有关。     

翅果形态及其在槭树科分类与演化上的意义

槭树科（Ａｃｅｒａｃｅａｅ）是北温带分布的科,含２属,全世界约２００种,中国是槭树科植物的现代分布中心。对槭树科翅果的专门研究尚未见报道。本文１、引用一套槭属翅果形态学术语;２、观察并描述７５种械属植物的翅果;３、研究槭属１６个组的翅果的１７个可比性状,根据分枝系统分析法得出槭属各组的演化关系及趋势,这趋势与依据其花、叶等性状得出的演化关系基本上是一致的。     

广西渐新统宁明组臭椿属(苦木科)的翅果化石及其分类学和生物地理学意义

描述广西渐新统宁明组近来发现的臭椿属(Ailanthus Desf.)翅果化石。通过对臭椿属翅果腹脉和花柱痕的位置以及翅果大小3个性状的比较形态学研究,广西宁明组的翅果化石被归入2个种,即古臭椿(A.confucii Unger)和塔德臭椿(A.tardensis Hably)。古臭椿过去广泛发现于欧亚和北美始新世以来的中纬度地区,其翅果腹脉位于边缘或边缘稍内、花柱痕与种子中部处于同一水平、长20—42mm,而广西宁明产的该化石种大多长40—53mm。塔德臭椿最早发现于匈牙利布达佩斯的下渐新统,其翅果腹脉位于边缘以内、花柱痕与种子顶部处于同一水平、长35—41mm,广西宁明则是该化石种的第2个产地。此外,过去还从斯洛文尼亚索卡(Socka)下渐新统报道了另外1个臭椿属翅果化石种巨臭椿(A.gigas Unger)(长达57mm),它与古臭椿唯一可以区别的性状是翅果长度。基于广西宁明和其它产地的古臭椿翅果化石形态特征的连续性,巨臭椿被处理为古臭椿的分类学异名。本文研究的2个臭椿属化石种是迄今纬度最低的该属化石报道。结合臭椿属现生种的地理分布、系统发育关系以及相关化石种的地理和地层分布,探讨该属的生物地理起源与演化历史。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.