自然植被净第一性生产力模型初探

 本文根据植物的生理生态学特点及联系能量平衡方程和水量平衡方程的区域蒸散模式建立了联系植物生理生态学特点和水热平衡关系的植物的净第一性生产力模型：该模型的建立为宏观地确定地带性景观的生产潜力、植物净第一性生产力的区域分布和全球分布，以及全球变化的影响提供了理论基础，对于合理地利用气候资源，扬长避短，充分发挥气候生产潜力，最大限度地提高植物的产量具有重要的意义。  

全球气候变化的中国自然植被的净第一性生产力研究

 本文根据已建立的植物生理生态学特点与水热平衡关系的植物净第一性生产力模型对中国自然植被的净第一性生产力现状及全球变化后的自然植被的净第一性生产力进行了分析，给出了中国陆地生态系统自然植被的净第一性生产力在全球气候变化条件下的变化图景，为合理开发、利用自然资源，以及监测和预测中国陆地生态系统自然植被净第一性生产力的变化及应采取的策略提供了科学依据。  

虫害诱导的植物挥发物:基本特性、生态学功能及释放机制

植物在遭受植食性昆虫攻击时，能通过释放挥发物调节植物、植食性昆虫及其天敌三者间的相互关系，并由此而防御植食性昆虫。主要就虫害诱导的植物挥发物的基本特性、生态学功能及其释放机制进行了系统性综述，并提出了今后的研究方向。  

植物的诱导抗虫性

植物对植食性昆虫的抗性可包括两个方面，即植物的组成抗性（constitutiveresistance）和诱导抗性（inducedresistance）。组成抗性是指植物在遭受植食性昆虫进攻前就已存在的抗虫特性；而诱导抗性是指植物在遭受植食性昆虫进攻后所表现出来的一种抗虫特性[1，2]。根据作用世代的不同，诱导抗性又分为迅速的诱导抗性（rapidlyinducedre－sistance，RIR）和滞后的诱导抗性（delayedinducedresistance，DIR）。前者是指对当前世代的植食性昆虫的影响，而后者是指对后续的1～几个世代的植食性昆虫的影响[2]。研究植物的诱导抗虫性，不仅能在…  

NDVI曲线与农作物长势的时序互动规律

利用气象卫星NOAA AVHRR资料，反演出农作物生育期内每日和旬度的NDVI数据，分析了NDVI时间曲线的波动与农作物生长发育阶段及农作物长势的响应规律，并以华北冬小麦为例，探讨了NDVI在冬小麦中生育期的积分值与农作物单产之间的相互关系。结果表明，利用长时间序列的NDVI数据，结合作物的物候历，可以实现作物长势的遥感监测和产量遥感估算。  

Characterization and functionality of cell surface molecules on human mesenchymal stem cells

We have characterized adhesion molecules on the surface of multipotential human mesenchymal stem cells (hMSCs) and identified molecules whose ligands are present on mature hematopoietic cells. Flow cytometric analysis of hMSCs identified the expression of integrins: alpha1, alpha2, alpha3, alpha5, alpha6, alphav, beta1, beta3, and beta4, in addition to ICAM-1, ICAM-2, VCAM-1, CD72, and LFA-3. Exposure of hMSCs to IL-1alpha, TNFalpha or IFNgamma up-modulated ICAM-1 surface expression, whereas only IFNgamma increased both HLA-class I and -class II molecules on the cell surface. Whole cell-binding assays between the hMSCs and hematopoietic cell lines showed that T lymphocytic lines bound hMSCs with higher affinity than lines of either B lymphocytes or those of myeloid lineage. Experiments using autologous T lymphocytes isolated from peripheral blood mononuclear cells showed that hMSCs exhibited increased affinity for activated T-lymphocytes compared to resting T cells by quantitative whole cell binding and rosetting assays. Flow cytometric analysis of rosetted cells demonstrated that both CD4+ and CD8+ cells bound to hMSCs. To determine the functional significance of these findings, we tested the ability of hMSCs to present antigen to T lymphocytes. hMSCs pulsed with tetanus toxoid stimulated proliferation and cytokine production (IL-4, IL-10, and IFNgamma) in a tetanus-toxoid-specific T cell line. Maximal cytokine production correlated with maximal antigen-dependent proliferation. These data demonstrate physiological outcome as a consequence of interactions between hMSCs and human hematopoietic lineage cells, suggesting a role for hMSCs in vivo to influence both hematopoietic and immune function(s).  

植物—植食性昆虫—天敌三营养层次的相互作用及其研究方法

根据国内外的最新研究成果 ,从他感化合物和植物的营养物质、有毒物质、形态特征、密度、多样性以及分布等化学和物理因子两方面阐述了植物、植食性昆虫及其天敌三营养层次间直接和间接的相互关系 ,揭示了植物在三者关系中的核心作用 ,并就目前在该领域中的一些常用的研究方法作了介绍 .  

Current velocity and invertebrate grazing regulate stream algae: results of an in situ electrical exclusion

Current velocity is a pervasive feature of lotic systems, yet this defining environmental variable is rarely examined as a factor for regulating stream herbivory. To investigate how current modifies herbivory in the upper Colorado River, U.S.A., loops of electrified fencing wire were used to reduce in situ grazer densities on 30 × 30 cm tile substrates. After 45 d, electrified tiles had significantly fewer grazers (P = 0.03) and >2X more algal biomass than controls (P = 0.0002). Reduced grazing on electrified tiles yielded periphytic assemblages having more diatoms and chlorophytes, as well as greater algal species richness. Current velocity effects alone did not significantly regulate algal abundance; however, the interaction between current velocity and grazer exclusion resulted in more algae in slow vs. fast current (P = 0.02). Grazer abundances were similar between fast and slow current velocities, suggesting that grazers in the Colorado River differ in their ability to regulate algae across the current velocity gradient. Our results indicate that stream current-mediated herbivory in streams may be more important than is generally recognized.