陕西黄龙山林区褐马鸡春季夜栖地选择

2006年4～6月,在陕西黄龙山林区,对褐马鸡(Crossoptilon mantchuricum)春季夜栖地的选择进行了研究.共记录到22个夜栖地,以夜栖树为中心做一个10 m×10 m样方,测定夜栖地海拔、坡向、坡度、坡位、地貌特征、夜栖树高度和胸径、乔木层盖度、乔木的数量、灌木层盖度、草本盖度、水源距离、人为干扰距离、林缘距离、栖枝高度和栖位上盖度等参数;通过9条样带测定54个随机样方,除栖枝高度和栖位上盖度外,指标相同.结果表明,褐马鸡春季夜栖地多偏向以坡度较大、山坡和山脊、接近水源、远离林边、人为干扰距离较远、乔木盖度和密度较大、栖树胸径较大、灌木层盖度和草本层盖度较小为主要特征的地方.主成分分析表明,前5个特征值的累积贡献率达到72.746%,可以较好地反映褐马鸡春季夜栖地生境特征.根据载荷系数绝对值大小,将褐马鸡春季夜栖地生境选择影响因子分别命名为地形和林下植被因子、气象因子、稳定性因子和水因子.影响褐马鸡夜栖地选择的关键因素是安全、舒适和栖息地转换的方便程度.     

贺兰山蓝马鸡越冬期栖息地的选择

2003年11～12月,在贺兰山采用样带法对蓝马鸡(Crossoptilon auritum)的栖息地选择进行了研究。共测定了25条样带上的62个蓝马鸡栖息地利用样方和50个任意样方的13个生态因子,结果表明,蓝马鸡偏好利用山地针叶林带,避免选择山地草原带、山地疏林草原带、亚高山灌丛和草甸带;偏好利用油松和青海云杉占优势的生境,避免选择山杨、杜松占优势和无树的生境;偏好阳坡和阴坡,避免利用半阳坡和半阴坡。对利用样方和任意样方进行Mann—Whitey U检验,发现利用样方以乔木密度高、灌木密度高、坡度大、隐蔽程度高、雪覆盖浅、高海拔为主要特征。逐步判别分析表明,隐蔽级、灌木密度、乔木密度、距水源距离和坡度具有重要作用,由这5个变量构成的方程对利用样方和任意样方进行正确区分的概率达到91．7％。蓝马鸡的栖息地选择主要与食物条件和隐蔽性有关。     

贺兰山区马鹿对冬季生境的选择性

2003年11—12月,在贺兰山采用样带法对马鹿阿拉善亚种的生境选择性做了研究。在选定的25条样带上一共测定了87个利用样方以及50个任意样方的14种生态因子(植被类型、优势乔木、坡向、坡位、食物丰富度、乔木密度、灌木密度、坡度、海拔高度、雪深、水源距离、人为干扰距离、裸岩距离和隐蔽级)。结果表明,马鹿对4种生态因子有选择性：①植被类型：偏好利用山地草原带和山地针叶林带,避免选择亚高山灌丛和草甸带;②优势乔木：偏好利用混合型的生境,避免选择杜松、油松和无树的生境;③坡向：偏好位于阳坡的生境,避免利用阴坡;④坡位：偏好位于下坡位的生境,避免选择上坡位和中坡位。对利用样方和任意样方进行比较,发现马鹿的利用样方以灌木密度高、食物丰富、坡度小、接近水源、雪覆盖浅、远离裸岩和人为干扰为主要特征。对各种生态因子的主成分分析表明前6个主成分的累积贡献率已经达到了84．89％,可以较好地反映马鹿的生境特征。第1主成分反映出马鹿在选择生态因子方面与植被类型、乔木密度、灌木密度、坡向、坡度、距水源距离、雪深、海拔高度正相关。     

陕西凤县春季林麝生境的初步分析

2006年4～5月,在陕西凤县共设置41个20 m×20 m的样方和14个生态因子,并以此为基础数据,分析结果表明,林麝春季喜欢选择在海拔1700～2100 m、灌木盖度、竹子密度、倒木密度、树桩密度、动物干扰程度均较低、坡度≥ 40°、半阴半阳坡、远离人类生产活动、有土质覆盖的生境.其他生态因子郁闭度、隐蔽级、乔木密度、灌木密度均以适中为准.因子分析的结果表明,前7个公共因子的累计贡献率达到76.63%,基本上反映了林麝春季栖息地的特征.在前7个公共因子中,占有较高信息载荷系数的变量依次为灌木盖度、树桩密度、乔木密度、活动基底、隐蔽级、人为干扰、竹子密度.     

贺兰山牦牛冬春季的生境选择

在2009年12月－2010年1月和2010年4－5月,采用样线法结合直接观察法对贺兰山牦牛的冬春季生境选择进行了研究。结果表明,牦牛冬季对11种生境因子有选择性,偏爱山地针叶林带,海拔小于2 000 m,优势乔木为灰榆,坡度小于10,下坡位,距水源距离大于1 200 m,人为干扰距离2 000－4 000 m,隐蔽级大于70 %;春季牦牛对13种利用生境生态因子有选择性,偏爱于亚高山灌丛和草甸带,海拔大于3 000 m,乔木密度小于1株,乔木高度小于3 m,乔木距离大于3 m,灌木密度大于4 0株,灌木距离小于1 m,植被盖度大于7 0 %,上坡位,距水源的距离小于8 00 m,人为干扰距离大于4 000 m,隐蔽级大于7 0 %。冬春季牦牛在海拔、植被类型、地形特征、优势乔木、灌木种类、坡位、坡向、人为干扰距离、距水源距离上存在显著差异。主成分分析表明冬季第一主成分的贡献率21.100 %,其中绝对值较大的相关系数是乔木距离、优势乔木、乔木高度和乔木密度;春季第一主成分的贡献率是31.247 %,其中绝对值较大的相关系数是植被类型、海拔高度、地形特征和灌木密度。与其他分布地区的牦牛相比,贺兰山地区的牦牛能适应当地的地理特征和气候环境。     

陕西黄龙山林区褐马鸡繁殖季节中午卧息地选择

2006年5—6月,在陕西黄龙山腹地北寺山林区采取样线法对褐马鸡(Crossoptilon mantchuricum)中午卧息地的选择进行了研究,共观察到28个褐马鸡的卧息地。褐马鸡对林型、坡向和地理特征有明显的选择性,多偏向针叶林、山脊和半阴半阳坡,回避阔叶林、山坡、阴坡和阳坡。对中午卧息地坡位没有明显的选择性。褐马鸡中午卧息地具有坡度小、与林间道路与居民点的距离远、灌丛平均高度较低、灌木密度较小、草本均高较小、乔木层植物盖度以及草本层植物盖度较大等特征。对各种生境因子的主成分分析表明,前6个特征值的累积贡献率达到74.05%,可较好地反映褐马鸡中午卧息地生境特征。根据载荷系数绝对值大小将褐马鸡中午休息地生境选择影响因子分别命名为地理因子、隐蔽度因子、人类活动干扰因子和灌丛密度因子。     

再引入黑颈长尾雉夏季栖息地选择

2008年6～7月,在广西岑王老山国家级自然保护区采用样带法对再引入黑颈长尾雉(Syrmaticus humiae)的栖息地选择进行了研究。共测定了7条样带上的22个栖息地样方和17个对照样方的24个生态因子。结果表明,再引入黑颈长尾雉的夏季栖息地偏向于选择海拔低、坡位低、乔木较低和灌木较高、落叶盖度较大、灌木层盖度大、草本高且盖度大的阔叶林、针阔混交林或者针叶林;逐步判别分析的结果显示坡位、草本层盖度是重要的生态因子,由这两个变量构成的方程在对栖息地和对照区进行区分时,正判率可以达到77.3%,这种选择与黑颈长尾雉的隐蔽条件和食物密切相关。     

秦岭周至自然保护区斑羚夏冬季生境选择利用

2014年2月、2014年12月—2015年1月和2015年6—7月,在陕西省周至自然保护区,采用样带法对斑羚冬季和夏季生境选择进行研究。结果表明,斑羚夏季对14种生境因子有选择性,而在冬季斑羚对16种生境因子有选择性。夏冬季斑羚对植被类型、坡位、海拔、坡度、郁闭度、乔木大小、乔木距离、灌木密度、灌木距离、灌木盖度、草本盖度、草本种类、距隐蔽物距离和距人为干扰距离的选择存在显著差异。逻辑斯蒂回归分析表明,坡向、坡位、乔木大小、乔木距离、灌木大小、隐蔽级、距隐蔽物距离、距人为干扰距离是斑羚夏季生境选择的主导因子。坡向、坡位、郁闭度、乔木距离、灌木大小、灌木距离、草本种类、隐蔽级、距水源距离是斑羚冬季生境选择的主导因子。     

四川铁布梅花鹿自然保护区梅花鹿夏季栖息地选择

四川梅花鹿Cervus nippon sichuanicus为国家Ⅰ级重点保护动物,四川铁布梅花鹿自然保护区分布有我国现存最大的梅花鹿野生种群。2011年6-9月,采用样方法对保护区梅花鹿夏季栖息地选择进行了调查,共布设109个样方(利用样方61个,对照样方48个),测量并比较了海拔、坡度等20个生境因子。结果显示,梅花鹿偏好利用的植被类型为灌丛、草甸、针叶林,同时选择隐蔽度较高的生境;此外,距水源距离、灌木高度、灌木盖度、灌木密度、草本高度和草本盖度6个连续变量在利用样方和对照样方之间差异有统计学意义(F<0.05或U<0.05)。回归模型分析结果表明,梅花鹿夏季偏好选择草本盖度大、靠近水源和林缘的生境,回避远离水源和林缘的生境。     

云南大中山黑颈长尾雉栖息地选择周年变化

采用比较利用和可利用栖息地的方法,分别对云南大中山黑颈长尾雉秋冬季、春季和夏季栖息地展开调查。检验和Bonferroni置信区间分析结果表明,黑颈长尾雉不同季节均偏向选择常绿阔叶林,偏向选择或回避选择的乔木、灌木和草本的种类不尽相同。利用和可利用样方差异性检验显示,不同季节对地形因素的选择性不明显,仅夏季距水源距离一个因子差异显著;植被因子中,春季差异显著的仅有乔木层盖度因子,夏季有乔木密度、乔木层盖度、落叶层盖度和草本层盖度等4个因子,秋冬季有乔木层盖度、草本层盖度和藤本密度等3个因子。主成分分析表明,不同季节利用样方负荷绝对值较大的因子在各主成分中的序位不尽相同,即栖息地选择的主要生态因子随季节发生变化。单因素方差分析和逐步判别分析表明,秋冬季与春季栖息地特征较接近,而与夏季差别较大。χ2     

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.     

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。     

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.     

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.     

Progress in glial cell studies in some laboratories in China

Glial cells in the central nervous system(CNS) consist of a heterogeneous population of cell types,each characterized by distinct morphological features,physiological properties,and specific markers.In contrast to the previous view that glial cells were passive elements in the brain,accumulating evidence suggests that glial cells are active participants in various brain functions and brain disorders.This review summarizes recent progress of glial cell studies from several groups in China,ranging from studie...     

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.