SH系砧木及对应中间砧红富士苹果枝条水分输导阻力研究

为进一步揭示砧木的矮化机理 ,以SH系矮化砧木及相应中间砧红富士苹果为试材 ,在生长季测定砧木枝条及嫁接部位的水分输导阻力。结果表明 ,SH系砧木枝条及嫁接部位的水分输导阻力 ,随砧木矮化程度的升高而增大 ,表明水分输导阻力的增加 ,是导致嫁接树矮化的原因之一。     

不同碳源对虎奶菇菌核蛋白质营养价值的影响

测定了四种碳源对虎奶菇菌核蛋白质营养价值的影响。结果表明，以玉米淀粉为碳源，虎奶薅菌蛋白质的化学评分，必需氨基酸指数，生物价和营养指数分别为11．63、69．80、64．40和9．98，均居四种参试碳源的第一位；氨基酸评分和氨基酸比值系数分分别为14．55和12．45，均居四种参试碳源的第二位，这些结果证实，以玉米淀粉为碳源，虎奶菇菌核蛋白质营养价值高，值得推广应用。     

Expression of undulin in experimental rat liver fibrosis

AIM: To observe the expression of undulin (Un) in liver tissue and to clarify the diagnostic significance of serum Un in experimental rat liver fibrosis. METHODS: Rat liver fibrosis was induced by carbon tetrachloride. The expression of Un in liver tissue was detected by immunohistochemical method. Serum Un levels was measured by enzyme immunoassay. RESULTS: Expression of Un increased in fibrotic liver than normal liver, and it was mainly distributed in portal tract stroma, central veins and fibrotic septa in fibrotic liver. Also, the level of serum Un was significantly higher in fibrotic liver than normal liver. CONCLUSION: These data suggest that Un should be a component of the hepatic extracellar matrix, and its expression could be increased greatly in fibrotic rat liver. Serum Un levels may be used as an indicator in liver fibrosis diagnosis.     

不同施氮量对甜椒碳、氮营养分配的影响

 通过水培试验，利用 N和”C双示踪技术研究了不同施氮量对甜椒结果期碳、氮营养分配的影响 结果表明：结果前期吸收的 N在低氮(NO3一N 2．5 mol·L～，NH4+一N 0．25 mol·L )营养处理下分配于果实中的比率高于中氮(NO；一N 5．0 mol·L～，NH —N 0．5 mol·L )和高氮(NO；一N 11．0 mol‘L～，NH4+一N 1．0 mol·L )营养处理。氮水平制约着 N在各器官中的分配和再运转，很少影响”C在器官间的分配，但却制约着”C的运转和再分配，表现为中氮营养最有利于 C向果实中的再运转。碳氮营养平衡有利于碳素向生殖器官的运转和积累，这是低氮营养产量前高后低，高氮营养产量前低后高，中氮营养前后期产量均较高的根本原因。     

草地生态系统碳循环研究进展

随着全球气候变化和陆地生态系统碳循环研究的发展,碳循环正成为草地生态系统研究的热点.本文在介绍其研究发展过程、主体内容和方向的同时,对目前的研究动态和研究方法进行系统的概述,重点分析了目前国内外草地生态系统碳循环过程研究、机制研究、研究方法及模型的发展动态,并对今后草地生态系统碳循环和相关研究提出了建议.     

碳纳米管的酸化处理对碳纳米管/聚氨酯复合材料微观结构及性能的影响

对多壁碳纳米管进行酸化处理,并采用原位聚合法制备了碳纳米管/聚氨酯复合材料。利用X射线光电子能谱分析(XPS)、电子扫描显微镜(SEM)、动态力学分析(DMA)研究了碳纳米管酸化与否对复合材料性能的影响。结果表明,碳纳米管经酸化处理后产生了羧基,碳纳米管的原位加入使得复合材料的储存模量和玻璃化转变温度都有所提高,而且经过酸化的碳纳米管对聚氨酯材料的改性要比未酸化碳纳米管对聚氨酯材料的改性效果更为显著。     

Earthworms increase soil microbial biomass carrying capacity and nitrogen retention in northern hardwood forests

Earthworms have been shown to produce contrasting effects on soil carbon (C) and nitrogen (N) pools and dynamics. We measured soil C and N pools and processes and traced the flow of ¹³C and ¹⁵N from sugar maple (Acer saccharum Marsh.) litter into soil microbial biomass and respirable C and mineralizable and inorganic N pools in mature northern hardwood forest plots with variable earthworm communities. Previous studies have shown that plots dominated by either Lumbricus rubellus or Lumbricus terrestris have markedly lower total soil C than uncolonized plots. Here we show that total soil N pools in earthworm colonized plots were reduced much less than C, but significantly so in plots dominated by contain L. rubellus. Pools of microbial biomass C and N were higher in earthworm-colonized (especially those dominated by L. rubellus) plots and more ¹³C and ¹⁵N were recovered in microbial biomass and less was recovered in mineralizable and inorganic N pools in these plots. These plots also had lower rates of potential net N mineralization and nitrification than uncolonized reference plots. These results suggest that earthworm stimulation of microbial biomass and activity underlie depletion of soil C and retention and maintenance of soil N pools, at least in northern hardwood forests. Earthworms increase the carrying capacity of soil for microbial biomass and facilitate the flow of N from litter into stable soil organic matter. However, declines in soil C and C:N ratio may increase the potential for hydrologic and gaseous losses in earthworm-colonized sites under changing environmental conditions.     

低碳经济下绿色证券市场资源配置研究

随着经济高速发展,高耗能、高污染的问题日益严重,通过绿色证券资源配置可以达到低碳、环保的目的。该文分析了绿色证券市场的资源配置模式,并对中国绿色证券市场的现状进行了分析;最后从上市条件、制度和立法等方面对提高绿色证券市场资源配置效率提出了具体的对策。     

西方国家碳税收入使用政策比较及其启示

碳税收入使用政策是西方国家碳税制度设计的一项重要内容，其主要基于税收中性原则，将税收收入或投资于环保节能项目，或以税式支出方式降低纳税人负担，确保碳税收入的循环，实现节能减排的目标。在我国碳税制度设计的构想中，应借鉴西方国家税制经验，结合本国现实情况，科学合理地设计碳税收入使用政策，确保碳税调节功能的充分发挥，将碳税发展成培育战略性新兴产业的重要政策工具之一。     

Shifts in microbial diversity through land use intensity as drivers of carbon mineralization in soil

Land use practices alter the biomass and structure of soil microbial communities. However, the impact of land management intensity on soil microbial diversity (i.e. richness and evenness) and consequences for functioning is still poorly understood. Here, we addressed this question by coupling molecular characterization of microbial diversity with measurements of carbon (C) mineralization in soils obtained from three locations across Europe, each representing a gradient of land management intensity under different soil and environmental conditions. Bacterial and fungal diversity were characterized by high throughput sequencing of ribosomal genes. Carbon cycling activities (i.e., mineralization of autochthonous soil organic matter, mineralization of allochthonous plant residues) were measured by quantifying ¹²C- and ¹³C-CO₂ release after soils had been amended, or not, with ¹³C-labelled wheat residues. Variation partitioning analysis was used to rank biological and physicochemical soil parameters according to their relative contribution to these activities. Across all three locations, microbial diversity was greatest at intermediate levels of land use intensity, indicating that optimal management of soil microbial diversity might not be achieved under the least intensive agriculture. Microbial richness was the best predictor of the C-cycling activities, with bacterial and fungal richness explaining 32.2 and 17% of the intensity of autochthonous soil organic matter mineralization; and fungal richness explaining 77% of the intensity of wheat residues mineralization. Altogether, our results provide evidence that there is scope for improvement in soil management to enhance microbial biodiversity and optimize C transformations mediated by microbial communities in soil.