50年来山东塔山植被与物种多样性的变化

为分析塔山植被与物种多样性50a自然演替和动态变化,2009-2010年,采用系统勘踏法和典型取样法进行了调查。当前塔山主要植被类型为"黑松林-赤松林-栓皮栎林"。50a间,该区针叶林从黑松(Pinus thunbergii)林演替为黑松林、赤松(P. densiflora)林和油松林(P. tabulaeformis)为主的混合针叶林,但针叶林的整体优势度下降,以栓皮栎(Quercus variabilis)和麻栎(Q. acutissima)为建群种的阔叶林面积明显增大,由针叶林向阔叶林的演替趋势明朗。物种丰富度为草本层>灌木层>乔木层,Shannon-wiener指数和Simpson指数为灌木层>草本层>乔木层,物种多样性较低,处于森林演替初期。     

大蜀山孤岛状山体植被演替阶段物种多样性变化规律

采用"空间差异代替时间变化"的研究方法,以位于安徽省合肥市的孤岛状山体——大蜀山国家森林公园的恢复植被为研究对象,调查了16个典型样地,利用丰富度指数(Margalef richness index,R)、Shannon多样性指数(Shannon diversity index,H)、均匀度指数(Pielou evenness index,Jsw)和生态优势度指数(Simpson index,D)等研究了4个不同演替阶段森林群落的特征变化。结果表明:从马尾松林向针阔混交林、麻栎林的演替过程中,群落乔木层Shannon指数分别为1.957、1.485、0.738,呈下降的趋势;而短毛椴林乔木层Shannon指数为1.694。麻栎林乔木层的物种丰富度和多样性显著低于其他3个群落(P0.05),均匀度显著低于马尾松林和短毛椴林(P0.05)。4种群落灌木层、草本层之间的多样性和均匀度差异均不显著(P0.05)。在群落的垂直结构中,麻栎林物种多样性表现为灌木层草本层乔木层,其他3种群落的物种多样性则表现为灌木层乔木层草本层。处于演替顶极群落的物种多样性并不是最高,群落演替过程的稳定性和多样性有着更为复杂的关系。除人为活动的干扰外,群落的发育程度和内部生境是影响该区演替阶段群落物种多样性变化的主要因素。     

岷江冷杉林皆伐后次生群落结构和物种多样性的演替动态

为阐明岷江冷杉林皆伐后次生群落的演替过程,采用空间代替时间的方法,在川西米亚罗林区海拔3100—3600 m的阴坡选择岷江冷杉林皆伐后次生演替10、20、30、40和50a阶段的次生群落作为研究对象,对其群落结构和物种多样性的动态进行了研究。不同演替阶段的树木均呈显著聚集分布。按群落中优势种的重要值将该演替序列划分为3个类型:悬钩子-蔷薇灌丛、白桦阔叶林和桦木-岷江冷杉针阔混交林。随次生演替,乔木和灌木种的物种丰富度趋于增加,而草本种的物种丰富度趋于减少;乔木和灌木种的Shannon-Wiener多样性指数趋于增大,而草本的Shannon-Wiener多样性指数趋于减小;乔木、灌木和草本层的Pielou均匀度指数均趋于增大;乔木层的Simpson优势度指数趋于减小,灌木和草本层的Simpson优势度指数在演替0—40年阶段趋于增大,而在演替50a阶段趋于减小。在该演替序列中,乔木、灌木和草本层的物种组成均呈耐荫种替代非耐荫种的趋势。     

北京九龙山植物群落物种多样性特征对比分析

根据对北京九龙山植物群落的样地调查数据,采用Shannon-Wiener多样性指数、群落均匀度和生态优势度指标研究了九龙山封育植被乔灌草各层的物种多样性,并分别就阳坡和阴坡进行了乔木材、灌价群落的指标对比分析,结果表明,这3种指标能够有效地表征暖温带植物群落的组成结构特征,在九龙山封育植被中,阴阳坡的灌丛群落与乔木材相比,其灌木层的物种多样性Shannon-Wiener指数D高于乔木林中乔木层,而低于其灌木层;灌丛群落的草本层Shannon-Wiener指数小于乔木材中草本层;乔木材的草本层的物种多样性Shannon-Wiener指数大于灌木层,灌木层又大于乔木层,而生态优势度系数C在上述3种比较中与Shannon-Wiener指数表现相反,而群落均匀度指数J在比较中阴阳坡的表现不同,最后讨论了九龙坡地区植被演替序列及加速其进展演替的恢复措施。     

浙江天台山甜槠群落物种多样性研究

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。灌木层的物种丰富度、多样性指数最大,乔木层次之,草本层最小。灌木层的群落均匀度明显大于乔木层,而乔木层、灌木层的群落均匀度与草本层差异不显著。乔木层、灌木层、草本层的多样性各项指标在群落各样地间均有一定的差异,相对而言,灌木层、乔木层的差异较小,草本层的差异较大。     

小流域治理20年后的千烟洲植物多样性

研究了小流域治理20年后千烟洲植物α多样性和β多样性,结果如下:1)优势度:所有人工林乔、灌、草3层均以乔木层优势度最大,且乔木层优势度均大于天然次生林和枫香(Liquidambar formosana)林,而所有天然次生林及枫香林均以乔木层优势度最小。12种类型群落灌木层优势度都较小,均值仅0.17。草本层,白茅(Imperata cylindrica var. major)草丛和檵木(Loropetalum chinense)-疏花雀麦(Bromus remotiflorus)灌丛优势度较大,分别为0.53和0.51。2)多样性:从乔、灌、草3层比较,枫香林、天然马尾松(Pinus massoniana)林以乔木层最大,其它群落以灌木层最大,而所有人工林以乔木层最低。乔木层中枫香林最高(2.61);灌木层和草本层多样性存在相似之处:马尾松 + 湿地松(Pinus elliottii)林最高,除马尾松+山鸡椒(Litsea cubeba)林、板栗(Castanea mollissima)+枫香林外,其它人工林多样性均高于天然次生林和枫香林。3)丰富度:各群落均以灌木层最大;枫香林乔木层和灌木层种类丰富度均很高,但草本层很低;天然次生林乔木层丰富度指数大于人工林。4)均匀度:从灌、草层比较,除檵木-疏花雀麦灌丛和白茅草丛外,其它群落草本层均匀度均大于灌木层。乔木层,板栗+枫香林和马尾松+山鸡椒林均匀度指数很大,大于0.76,其它人工林均匀度小于天然次生林和枫香林。灌木层,除板栗+枫香林外,其它人工林均匀度都大于天然次生林和枫香林。5)β多样性与α多样性相互补充,很好地反映了不同群落类型之间的差异。β多样性将12种类型群落分成3大类,草丛、灌丛、具乔木层的群落,其中草丛与其它类型群落相异性最大。枫香林是位于人工林与天然次生林之间的过渡类型。     

白龙江上游地区森林植物群落物种多样性的研究

 白龙江上游地区属长江防护林工程重点地区之一。根据36个样地的调查资料,分析了该地区森林植物群落物种多样性的特征：群落内各层物种丰富度指数的大小顺序为“灌木层>草本层>乔木层”;均匀度指数变化比较复杂,在杜鹃巴山冷杉（Rhododendron fastigiatum-Abies fargesii）林中为“草本层>灌木层>乔木层”,在苔藓巴山冷杉林中为“乔木层>灌木层>草本层”,其余群落中为“灌木层>草本层>乔木层”;多样性指数的大小顺序为“乔木层<灌木层和草本层”,而灌木层与草本层的多样性指数随林分郁闭度变化而变化,在郁闭度30%的杜鹃巴山冷杉林中,草本层大于灌木层,在郁闭度47%的箭竹巴山冷杉林中,草本层和灌木层相当,在郁闭度55%以上的各个群落内,灌木层大于草本层。同一海拔不同坡向群落的物种多样性表现为分布于阳坡的油松（Pinus tabulaeformis）林大于分布于阴坡的草类云杉（Picea asperata）林。物种多样性沿海拔梯度的变化表现为随海拔升高先降低后增加,从海拔2 400 m的栎类阔叶林,2 600 m的草类云杉林,2 800 m的箭竹(Sinarundinaria nitida)巴山冷杉林,到3 000 m的苔藓巴山冷杉林和3 200 m的杜鹃巴山冷杉林,物种多样性依次下降,到海拔3 400 m的高山杜鹃（Rhododendron fastigiatum）灌丛,物种多样性增加。物种多样性在紫果云杉(Picea purpurea)林的演替系列中表现为随群落演替发展而增加,后降低,在针阔混交林阶段达到最大。     

海南俄贤岭石灰岩山地海南大戟灌丛群落研究

根据样方调查,对海南俄贤岭自然保护区海南大戟灌丛群落的种类组成、外貌、结构特征和物种多样性进行分析。结果表明,在700m2样地中,有维管植物77种,隶属于47科70属。群落中乔木的个体数量很少,主要由灌木和草本组成,灌木层主要优势种为海南大戟等。群落外貌常绿,生活型以小高位芽为主,占22.08%;按照Raunkiaer的频度等级定律,属于B级的种类最多,频度值为43.42。整个群落的物种丰富度Magarlef指数为8.56,Shannon-Wiener指数为1.38,Simposon为0.90,均匀度指数为0.32。群落各层次的丰富度格局表现为灌木层>草本层>乔木层>藤本植物,多样性格局为灌木层>乔木层>草本层<(>)藤本植物,均匀度格局为乔木层>藤本植物>灌木层>草本层。     

百花山植物群落物种多样性研究

基于百花山50个样方的调查资料，从不同类型群落的物种多样性及其与海拔的关系等方面对百花山植被进行了分析，并且用DCA排序和海拔高程排序对物种多样性在环境梯度上的分布格局进行了初步研究。结果表明：群落内不同生长型的物种丰富度指数在森林群落中大小顺序为草本层＞灌木层＞乔木层，灌丛群落主要表现为草本层﹥灌木层，只有荆条灌丛表现为灌木层＞草本层；Shannon-Wiener指数在山杨—华北落叶松群落中表现为灌木层＞草本层＞乔木层,其他森林群落为草本层＞灌木层＞乔木层，在灌丛群落中主要表现为草本层＞灌木层，只有荆条灌丛表现为灌木层＞草本层；均匀度指数在灌丛群落中表现为灌木层＞草本层，在辽东栎林和山杨—华北落叶松林中表现为灌木层＞乔木层＞草本层,而其他森林群落表现为乔木层＞灌木层＞草本层。物种多样性在DCA第一轴排序和海拔高程梯度上都表现出单峰曲线变化趋势，但拟和效果的显著程度不同：丰富度和均匀度指数在海拔高程上曲线的拟和效果优于DCA环境梯度排序效果；而多样性指数则相反。     

广西阳朔岩溶植被演替过程种群变化及物种多样性

采用时空替代法研究广西阳朔岩溶植被在演替过程中的种群变化和物种多样性。研究表明,随着演替的进展,耐荫种群增加,乔木种群增加,优势种的更替呈现出一定的连续性,后一演替阶段的优势种往往已经隐含在前一演替阶段中;物种丰富度随演替进展表现出草丛<落叶阔叶林<灌丛<常绿落叶阔叶混交林的趋势;灌木层的物种丰富度在各演替阶段中均是最高的;在各演替阶段中,落叶阔叶林阶段的群落均匀度均表现为最大。     

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.     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义。综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望。     

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.     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

2018年中国植物科学若干领域重要研究进展

2018年中国植物科学继续呈现快速发展的态势, 我国科学家在国际植物科学主流学术刊物发表论文数量大幅增加, 取得了多项具有重要影响的成果。调控植物生长-代谢平衡实现可持续农业发展入选2018年度中国科学十大进展; 中国被子植物区系进化历史研究入选2018年度中国生命科学十大进展。以水稻为代表的农作物和果蔬等经济作物研究在国际上已呈现出明显的优势, 若干领域已从“追赶”状态跨越到“领跑”地位。该文对2018年中国科学家在植物科学若干领域取得的重要研究成果进行了概括性评述, 旨在全面追踪和报道当前中国植物科学领域的发展前沿和热点, 展示中国科学家所取得的杰出成就。     

2017年中国植物科学若干领域重要研究进展

2017年中国植物科学继续保持高速发展态势, 重大成果频出, 具体表现在中国植物学家在国际顶级学术期刊发表的文章数量平稳上升。中国植物科学领域的研究工作者成果精彩纷呈, 如新型广谱抗病机制的发现、水稻广谱抗病遗传基础及机制和疫霉菌诱发病害成灾机制研究等。2017年中国生命科学领域十大进展评选中, 有两项植物科学领域的研究成果入选。水稻生物学、进化与基因组学和激素生物学等领域学科发展突出。另外, 值得一提的是, 长期从事高等植物与代谢途径调控分子网络研究和水稻品种设计育种的李家洋院士的研究成果“水稻高产优质性状形成的分子机理及品种设计”荣获2017年国家自然科学一等奖。这一具有重大国际影响的开创性贡献标志着中国植物科学在该领域的国际科学前沿居于引领和卓越地位。该文对2017年中国本土科学家在植物科学若干领域取得的重要研究成果进行了系统梳理, 旨在全面追踪和报道当前中国植物科学领域发展的最新前沿动态, 与广大读者共同分享我国科学家所取得的辉煌成就。     

我国葫芦科植物离体培养研究进展

葫芦科植物包括多种瓜类蔬菜,对其进行离体培养研究具有重要的理论和实践意义.综述了国内在葫芦科植物器官培养、体细胞胚胎发生、花药培养、原生质体培养和体细胞杂交及离体遗传转化等方面取得的研究进展,并对葫芦科植物离体培养、遗传转化与育种的前景作了展望.     

Changes in aquatic vegetation in Rhine floodplain streams in Alsace in relation to disturbance

Abstract. Changes are described in aquatic vegetation in oligotrophic, groundwater-fed Rhine floodplain streams in Alsace (eastern France), resulting from disturbance. Disturbance factors include changes in nutrients, either permanent ones - effluent from a waste water treatment plant or trout hatcheries - or periodic ones: flooding. Regular inputs of high levels of phosphate and ammonia modified the macrophyte vegetation in these streams. The floristic composition, which was characteristic of oligotrophic waters upstream of the eutrophicated sector, changed to that of a eutrophic situation as originally found downstream. Periodic disturbance by floods which normally occur once a year, irregularly eutrophicates the small streams, causing the development of a mixture of eutrophic and oligotrophic species. Six macrophyte communities are distinguished, indicating different trophic levels. The aquatic vegetation is adapted to the variations of phosphate and ammonia levels. Hence, aquatic macrophytes can be used as bio-indicators of fluctuations in water nutrient levels in relation to the type of disturbance.     

Morphine-potentiated platelet aggregation in in vitro and platelet plug formation in in vivo experiments

The detailed mechanisms underlying morphine-signaling pathways in platelets remain obscure. Therefore, we systematically examined the influence of morphine on washed human platelets. In this study, washed human platelet suspensions were used for in vitro studies. Furthermore, platelet thrombus formation induced by irradiation of mesenteric venules with filtered light in mice pretreated with fluorescein sodium was used for an in vivo thrombotic study. Morphine concentration dependently (0.6, 1, and 5 microM) potentiated platelet aggregation and the ATP release reaction stimulated by agonists (i.e., collagen and U46619) in washed human platelets. Yohimbine (0.1 microM), a specific alpha(2)-adrenoceptor antagonist, markedly abolished the potentiation of morphine in platelet aggregation stimulated by agonists. Morphine also potentiated phosphoinositide breakdown and intracellular Ca(2+) mobilization in human platelets stimulated by collagen (1 microg/ml). Moreover, morphine (0.6-5 microM) markedly inhibited prostaglandin E(1) (10 microM)-induced cyclic AMP formation in human platelets, while yohimbine (0.1 microM) significantly reversed the inhibition of cyclic AMP by morphine (0.6 and 1 microM) in this study. The thrombin-evoked increase in pH(i) was markedly potentiated in the presence of morphine (1 and 5 microM). Morphine (2 and 5 mg/g) significantly shortened the time require to induce platelet plug formation in mesenteric venules. We concluded that morphine may exert its potentiation in platelet aggregation by binding to alpha(2)-adrenoceptors in human platelets, with a resulting inhibition of adenylate cyclase, thereby reducing intracellular cyclic AMP formation followed by increased activation of phospholipase C and the Na(+)/H(+) exchanger. This leads to increased intracellular Ca(2+) mobilization, and finally potentiation of platelet aggregation and of the ATP release reaction.     

Apoptosis in experimental myocardial infarction in situ and in the perfused heart in vitro

We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions.