午潮山常绿次生阔叶林主要木本植物功能群及其演替特征

为了理解午潮山次生林群落结构和演替特征,分析了不同演替阶段功能群物种的生态位和种间关系。对研究区70个20×20 m森林样地内胸径≥1 cm的木本植物进行分析调查,并按照11个功能性状（叶片氮含量、叶片磷含量、叶片钾含量、比叶面积、木材密度、叶片干物质含量、叶片叶绿素含量、生长型、寿命、喜光性和最大潜在树高）将主要的45个物种划分为4个功能群：早期先锋树种（PFG1）、中期中性树种（PFG2）、中后期树种（PFG3）和后期耐阴树种（PFG4）。结果表明种间正负联结比接近1,但显著正联结多于显著负联结,群落整体稳定,而演替中后期功能群（PFG2、PGF3和PFG4）的种间生态位重叠和种间联结强度较高,种间竞争激烈。午潮山森林群落正向演替后期发展,可伐除部分与演替中后期树种相互竞争的早期树种加速演替,并且补植有价值的喜阳先锋种减少开放地,为修复森林生态系统和加速群落演替提供策略。     

浙江天童披针叶茴香群落种间联结性研究

通过基于2×2列联表的种间联结分析和,检验,对浙江天童保存较好的披针叶茴香（Illicium lanceolatum A．C．Smith）群落的种间联结性进行研究,以揭示披针叶茴香在群落中的地位及种间联结与群落稳定性的关系。结果表明：（1）群落内所有树种间总体呈显著正联结[W（49．607）〉x0.05,32^2（46．194）];群落内所有物种间显著正联结的种对数比例高于显著负联结的种对数比例,但无显著联结种对数的比例最大。这表明群落处于稳定共存的状态。（2）披针叶茴香与石楠、尖萼毛柃、苦槠、四川山矾等7种呈显著正关联,仅与枫香呈显著负联结,与多数种间联结性不显著;披针叶茴香与多数种的联结系数（AC）值大于0．5（74．3％）,其中正联结种对数明显多于负联结种对数,表明披针叶茴香在群落中处于优势地位,与多数种群互利共存。此研究结果对制定该物种合适的就地保护措施、种群恢复以及人工规模栽培配置模式、生境的选择具有重要参考价值。     

井冈山自然保护区栲属群落优势种群的种间联结关系研究

 采用2×2联列表,通过方差分析、χ2检验、联结系数AC值、Jaccard指数及点相关指数对井冈山栲属（Castanopsis）群落样地中出现频率较高的20个种群的种间联结进行了定量分析。结果表明：井冈山栲属群落20个优势种群的总体种间关联性呈显著正关联,反映该群落处于稳定的顶极阶段;20个优势种群的种间联结关系中10个种对具有极显著正联结,10个种对具有显著正联结,4个种对具有极显著负联结,8个种对具有显著负联结。190个种对中,绝大多数种对联结关系未达到显著水平,种对间的独立性相对较强,这种种间联结的松散性可能与目前群落的发展阶段及种本身的生态学特性有关。目前,群落处于比较稳定的顶极阶段。     

苏门白酒草对乡土植物群落种间联结性及稳定性的影响

根据2×2列联表,运用方差比率（VR）,χ2检验和Jaccard指数以及改良的Godron M.稳定性测度方法,研究江西省上饶市苏门白酒草群落中12个主要种群间的联结性。结果表明：(1)苏门白酒草入侵前群落总体联结性为显著正联结,群落中的正联结种对多,存在极显著正联结种对;(2)苏门白酒草入侵后,群落总体种间联结性呈负相关,种对正联结数量较入侵前明显减少,出现显著负联结种对;(3)苏门白酒草入侵后,联结性较强的乡土群落植物明显分为两个生态种组;(4)苏门白酒草的入侵导致乡土植物群落稳定性下降,16个原有物种消失,出现4个新物种。     

塔里木河中下游地区荒漠河岸林群落种间关系分析

采用 2× 2列联表, 应用Fisher精确检验法研究了新疆塔里木河中下游荒漠河岸林群落种间关系, 测定了16种植物、共 12 0个种对的种间联结性。研究结果表明 :1) 12 0个种对中有 17个种对分别在不同的样方尺度中表现出显著或极显著的种间联结, 约占总数的 14.2 % ;其中 13个种对为正关联, 4个种对为负关联 ;2 ) 不同取样面积对种间联结性分析的有效性有影响, 不同种对表现出种间联结的最小样方尺度不同 ;3) 随着样方面积的增大, 各种对自有不同的种间联结变化规律, 可归纳为 4种类型 ;4 ) 17个具种间联结的种对以灌木草本和草本草本的种对居多, 占总数的 76.5 % ;主要乔木树种胡杨 (Populuseuphratica) 与灌木之间、灌木和灌木之间趋向独立分布。     

武夷山风景名胜区天然林乔木层主要种群的种间联结性研究

在相邻格子抽样调查的基础上,采用X2检验、联结系数(AC)和Jaccard指数(JI)等指标,分析了武夷山风景名胜区天然林乔木层主要种群的种间联结性。结果表明,15个主要种群间的总体联结性极显著相关。除少数种对外,绝大多数种对间的联结性不显著。在联结性显著的种对中,毛竹-木荷(Phyllostachys edulis-Schima superba)、黄瑞木-卷斗青冈(Adinandra mellettii-Cyclobalanopsis pachyloma)及卷斗青冈-杨梅叶蚊母树(Cyclobalanopsispachyloma-Distylium myricoides)间存在显著正联结,而种对马尾松-杉木(Pinus massoniana-Cunninghmialanceolata)、马尾松-青冈(Pinus massoniana-Cyclobalanopsis glauca)、杉木-毛竹(Cunninghmia lanceolata-Phyllostachys edulis)、杉木-米槠(Cunninghmia lanceolata-Castanopsis carlesii)、杉木-木荷(Cunninghmia lanceolata-Schima superba)及杉木-黄瑞木(Cunninghmia lanceolata-Adinandra mellettii)等27个种对间存在较高的负联结。     

崖柏群落优势乔木树种种间关系

采用样方调查法,对组成崖柏群落的乔木树种进行调查。通过计算重要值确定崖柏群落优势乔木树种,研究优势树种的总体联结性、2物种间的联结性和种间协变。结果表明:崖柏群落内的15个优势树种总体间存在负关联;2物种间具有显著正联结的种对有:高山栎-川陕鹅耳枥、高山栎-华中八角、大叶青冈-乌岗栎、铁杉-华西花楸、华千金榆-青榨槭、华千金榆-大叶青冈、大叶青冈-川鄂山茱萸、川陕鹅耳枥-华中八角;呈显著负联结的种对是高山栎-青榨槭;崖柏与其他优势树种的联结性均未达到显著程度;有26个种对表现出明显的正协变,12个种对表现出明显的负协变;种对正协变的存在是由于这些物种对环境资源的利用具有相似性所致。     

水淹干扰对水库水滨带植物群落稳定性与种间关系的影响

受城市化与人类活动等因素影响而退化的水滨带植被的恢复与重建是近年来生态环境的热点问题。植物群落的种间关系直接影响植被的演替与恢复。以南水北调中线一期工程通水前的丹江口水库原有水滨带植被为研究对象,对年均多于9个月（海拔142 m以下）、6-9个月（海拔142-147 m）、3-6个月（海拔147-151 m）和少于3个月（海拔151-157 m）的4种不同强度水淹干扰的水滨带植物群落的稳定性和种间关系进行分析,探讨不同水淹干扰强度对水库水滨带植物群落稳定性及种间关系的影响。采用M.Godron稳定性测定法对植物群落稳定性进行分析,通过方差比率（VR）、χ²检验、联结系数（AC）以及Spearman秩相关检验对不同水淹干扰强度下的植物群落优势种进行种间关联分析。结果表明：（1）水库水滨带植物群落稳定性从高到低依次为水淹时长3-6个月、水淹时长6-9个月、水淹时长少于3个月和水淹时长多于9个月。中度水淹干扰下的植物群落稳定性要好于重度和轻度水淹干扰的植物群落;（2）不同水淹干扰强度下水滨带植物群落总体性关联表现为显著正相关。随着水淹时间增加,群落中正联结种对占总对数的比例呈下降趋势,负联结种对比例呈增加趋势,正负联结比值降低,群落内种间联结强度逐渐降低,说明水淹干扰强度增加会导致水滨带植物群落种群间相互依存关系减弱或竞争关系加剧。在此基础上,探讨不同水淹干扰强度下物种的空间分布和生态习性,并提出针对不同水淹干扰强度的水滨带植被恢复的物种选择建议。     

乌兰布和沙漠天然白刺种群及主要伴生种种间关联性研究

采用2×2列联表,运用方差比率法（VR）、χ²统计量检验、联结系数（AC）和共同出现百分率（PC）等指标,以关联测度指标（OI、DJ、JI）为参考,对内蒙古自治区乌兰布和沙漠天然白刺（Nitraria tangtorum）种群及其伴生种的种间关联性进行分析,结果表明：天然白刺种群内8个主要物种总体关联性表现为无关联。在全部的28个种对中,15个种对表现为正联结,13个种对间表现为负联结。种对中除白刺–沙蒿表现为显著负联结外,其他种对间联结性均不显著。主要物种白刺与草本,草本与草本之间趋向独立分布。通过对天然白刺种群总体以及种间的关联性研究,为构建稳定的沙漠植物群落、恢复重建沙漠地区的植被、改善沙漠地区生态格局提供理论指导。     

江西九连山自然保护区栲属群落优势种群的种间联结关系

采用2×2联列表,通过方差分析、χ2检验、联结系数AC值、JI指数对江西九连山栲属Castanopsis群落样地重要值前20的种群种间联结进行定量分析。结果表明,九连山栲属群落20个优势种群总体种间的正关联性不显著;但20个优势种群的种间联结关系中3对具显著正联结,2对具极显著正联结,1对具显著负联结,3对具极显著负联结。190个种对中,大多数种对联结关系未达显著水平,种对间的独立性相对较强。种群间的正联结性与种群重要值的关系分析表明,重要值高的种群间形成明显正联结性的种对数量最多,重要值高的种群与重要值低的种群之间形成明显正联结性的种对数量次之,重要值低种群间形成明显正联结性的种对数量最少。目前,群落正处于向顶级稳定群落演替的状态。     

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.     

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。     

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。     

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.     

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.     

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.