浙江天台山甜槠群落物种类多样性研究

对浙江省天台山甜槠群落的不同样地、不同层次的物种丰富度、物种多样性指数和群落均匀度进行了分析。结果表明：木本植物的物种丰富度、物种多样性指数明显大于草本植物;而群落均匀度两者无显著差异。在群落垂直结构中,乔木层第二亚层的物种丰富度、物种多样性指数均显著大于第一亚层,它们之间的群落均匀度差异不显著。灌木层的牧种丰富度、多样性指数最大,乔木层次之,草木层最小。灌木层的群落均匀度明显大于乔木层,而乔木层     

浙江天台山七子花群落物种多样性

以浙江省天台山七子花群落为对象,分析了七子花群落的植物区系组成和高等植物物种多样性。据９个样地统计,共有维管植物６９科、１４３属、１８６种（含变种）。从种子植物属的地理成分来看,温带分布的类型居多。在群落垂直结构中,乔木层第２亚层的物种丰富度、物种多样性指数均显著大于第１亚层,它们之间的均匀度差异不显著。乔木层与灌木层之间多样性各项指标无显著差别。乔木层、灌木层的物种丰富度、物种多样性指数均明显大     

天目山保护区森林群落植物多样性对毛竹入侵的响应及动态变化

为探讨毛竹(Phyllostachys edulis)入侵对周围森林群落的影响,作者于2005-2011年在天目山自然保护区进行了7年长期定位观测实验,研究了毛竹入侵地森林群落的植物物种多样性变化.结果表明:毛竹入侵对周围森林群落植物物种多样性产生了不利影响:毛竹林乔木层和灌木层植物的Simpson指数小于针阔混交林和毛竹-针阔混交林,而草本层的Simpson指数则大于针阔混交林和毛竹-针阔混交林.植物物种丰富度、Simpson指数和Pielou均匀度指数随时间发生了较大变化:毛竹入侵的森林群落其乔木层和灌木层的物种丰富度、Simpson指数和Pielou均匀度指数显著降低(P＜0.05),草本层的物种丰富度显著提高(P＜0.05),Simpson指数和Pielou均匀度指数未表现出明显的变化.毛竹-针阔混交林去除毛竹后,乔木层和灌木层物种丰富度和Simpson指数增加,草本层物种丰富度、Simpson指数和Pielou均匀度指数明显下降.可见,毛竹入侵使森林群落植物多样性发生实质性的变化,对自然保护区植物群落造成了重大影响.由此可见,要使保护区物种多样性得到保护,除进行科学的管理外,还需要控制毛竹蔓延.     

幕阜山森林群落结构与物种多样性研究

幕阜山地处中亚热带-北亚热带过渡地带,物种资源丰富.通过对其典型样地的调查,分别采用Shannon-Wiener指数、Simpson指数和Pielou均匀度指数作为测度指标,研究了幕阜山地区森林群落结构及其物种多样性特征.结果表明,该地区主要有21个森林群落类型.其中常绿阔叶林中,物种丰富度指数与多样性指数在群落梯度上的总体趋势均为灌木层相对高于乔木层,乔木层相对高于草本层;在落叶阔叶林中,其丰富度指数的趋势为灌木层＞草本层和乔木层,而在草本层与乔木层间是波动的,多样性指数的趋势为灌木层＞草本层＞乔木层;在针叶林中,物种丰富度、多样性指数表现的总趋势基本一致,即灌木层的丰富度相对较高,其次为草本层,乔木层的相对较小.在其他群落类型中,多样性指数、均匀度指数在乔木层、灌木层和草本层则表现出多样化的趋势;另外,从总体上看,各种指数在海拔梯度上并未表现出明显的规律性.     

北京东灵山地区植物群落多样性的研究Ⅱ丰富度、均匀度和物种多样性指数

本文以１２５块植物群落调查样地资料为基础，从不同类型、层次的丰富度、均匀度和物种多样性指数及其与海拔的关系等方面对东灵山地区植物群落多样性进行了分析。本区亚高山草甸植物群落多样性沿海拔梯度的变化规律是：物种丰富度和物种多样性指数随海拔升高而下降；物种均匀度则随海拔升高而增加。植物生长型与群落多样性指数的关系表现为“乔木层、灌木层物种丰富度指数相近且明显低于草本层；灌木层和草本层的均匀度指数相近，群落间变异幅度较小，乔本层则变异幅度很大；物种多样性指教则表现出草本层＞乔本层＞灌木层的规律。物种盖度和地上生物量作为测度指标计算群落多样性所得结果相近，且优于以株数作为测度指际计算的结果。     

山西历山国家级自然保护区猕猴栖息地森林群落物种多样性

在对山西历山国家级自然保护区猕猴栖息地森林群落进行数量分类的基础上,运用丰富度指数、物种多样性指数和均匀度指数方法对该地区森林群落的物种多样性进行了研究,并分析了森林群落各层片之间的物种多样性的相关性。结果表明:(1)栖息地森林12个群丛的丰富度指数、物种多样性指数和均匀度指数能够较好地反映各群落多样性变化规律。(2)栖息地森林群落的Patrick丰富度指数(R)与Shannon多样性指数(H)、Hill多样性指数(N1和N2)、Alatalo均匀度指数(E)和Pielou均匀度指数(Jsw)变化趋势基本一致,而Simpson多样性指数(λ)与H的变化呈相反趋势。(3)栖息地森林群落内乔、灌和草3层的丰富度指数、物种多样性指数和均匀度指数表现出多样化的趋势。各层片的丰富度指数和物种多样性指数总体上呈现草本层乔木层灌木层,但各片层的均匀度指数存在差异,其中灌木层的均匀度指数差异较大,而乔木层和草本层均匀度在各群落间差异较小。     

太白山北坡落叶阔叶林物种多样性特征

对太白山北坡落叶阔叶林从不同类型,层次的丰富度,均匀度和物种多样性指数及其与环境梯度的关系等方面进行了分析。结果表明,处于中山带的锐齿槲栎林及辽东栎林的多样性较高,高海拔与低海拔处的群落多样性较低。水热梯度对物种多样性有很大影响。植物生长型与物种多样性的关系表现为灌木层的多样性指数（Ｄ）和均匀度大于草本层,而草本层大于乔木层,草木层物种丰富度最大,灌木层次之,乔木层最小,不同群落间灌木层各多样性测     

浙江仙居俞坑森林群落物种多样性研究

分别采用物种丰富度、物种多样性指数和群落均匀度指标对浙江省仙居县俞坑森林群落的物种多样性进行测定和分析。结果表明：本木植物的物种多样性以生境优越的常绿阔叶林为高,木本植物的物种丰富度、物种多样性指数明显大于草本植物。在群落垂直结构中,木本植物等2层的物种丰富度、物种多样性指数均显著大于第1层。物种丰富度以木本第3层最大,草本层最小;而物种多样性指数、群落均匀度则以木本第2层最大、草本层最小。木本植物各层次、草本层的物种多样性各项指标在群落各样地间均有一定的差异。     

福建永定县笔架山桫椤群落物种多样性研究

对福建省永定是笔架山桫椤群落的不同样地,不同层次的物种丰富度,物种多样性指数和群落均匀度进行了分析。结果表明：在群落垂直结构的5个层次中,桫椤的物种多样性除物种丰富度外其他各项指标在各层次中是最大的;草本层的物种丰富度,多样性指数和种间相遇机率分居第2位,群落均匀度则居第3位;灌木层的物种丰富度居第1位,但群落均匀度最小;乔木层第1亚层的物种多样性各项指标除群落均匀度居第2位外,其他均最小;藤本的物种多样性各项指标要私居第3位,要私居第4位,样地间,乔木层,灌木层的各项多样性指标差异较小,草本层和藤本的差异较大,结果还表明;永定桫椤群落的Simpson指数和种间相遇机率（PIE）的数值几乎相等。     

北京松山自然保护区森林群落物种多样性及其神经网络预测

物种多样性是群落结构和功能复杂性的一种度量,物种多样性的空间分布格局受许多环境因子的影响.运用多样性指数,多层感知器网络,分析了松山保护区森林群落物种多样性与群落类型、结构和生境之间的关系.结果表明:(1)大果榆+山杨混交林、油松+青杨混交林物种丰富度、多样性和均匀度均较高,而大果榆林、华北落叶松林的各项指数值均较低.Patrick指数和Shannon-Weiner指数在森林群落中均表现为草本层＞灌木层＞乔木层;Pielou指数在榆林中表现为草本层＞乔木层＞灌木层,而在其他森林群落中表现为灌木层＞草本层＞乔木层.(2)功能层物种多样性在海拔梯度上的变化趋势不同,在乔木层,丰富度、多样性和均匀度随海拔的升高逐渐降低;在灌木层,丰富度、多样性和均匀度均呈比较明显的单峰曲线变化趋势;在草本层,丰富度和多样性随海拔的升高都呈下降趋势,而在草本层,均匀度变化不大.(3)用多层感知器网络预测功能层多样性效果很好,结果发现坡向对乔木层和灌木层物种多样性的影响最大,而海拔高度对草本层物种多样性的影响最大.     

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.     

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.     

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.     

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.     

Polymorphism in Cepaea Hortensis in marginal populations in Spain

Cepaea hortensis (Mull) is found in Spain only in the western part of the Iberian mountain range. This is the southernmost limit of its range. The most frequent colour is yellow, brown being very rare. The most frequent band patterns are 12345, fused banded and unbanded. There are associations between maximum and minimum temperatures and pink and effectively unbanded yellow phenotypes. The populations may be grouped into two zones, one located in the north and the other in the south of the sampled area. Visual predation was not observed. The marginal populations studied by us were compared with others from Northern Europe, and it was observed that pink snails are more frequent at the southern limit, and unbanded ones at the northern limit. This was interpreted as a climatic selection.