杉木、马尾松轮作对林地土壤肥力和林木生长的影响

研究了杉木、马尾松人工林轮作对林地土壤肥力和林木生长的影响。结果表明：与连作相比，轮作林分土壤微生物数量增多，酶活性增强、土壤酚类物质减少、土壤酸度降低，盐基总量和盐基饱和度提高以及土壤有效养分增加，并由此导致了林分生长量的提高。轮作林分土壤肥力提高，林分生长量增加的实质在于：人工林林分实施轮作后，由于后茬植物与前茬植物种类的不同导致土壤微生物种类和数量增多，土壤生物活性增强，并由此而导致土壤酸度降低，有毒物质减少，速效养分增加。     

天然抗氧化剂的提取分离及功能研究

天然抗氧化剂是一类重要的生物活性物质,由于它可以清除人体代谢过程中产生的自由基而具有延缓机体衰老的功效.因此,研究抗氧化剂对于保障人体健康、抗老防衰、防止食品腐败等方面具有重大意义.本文在对枣中多酚物质提取和功能研究的基础上综述了天然抗氧化剂的种类、作用机理、提取分离、结构鉴别及其功能分析,旨在开发和利用天然抗氧化剂.     

枣中糖测定的研究进展

综述了枣中糖的分离、提纯和测定的研究进展，并对目前研究存在的问题及以后的发展前景进行了讨论。     

超临界CO2萃取测定食品中总脂肪的研究

超临界CO2(S-CO2)萃取用于测定食品中的总脂肪含量，是一种很有前途的方法。文中具体介绍了测定总脂肪的S-CO2萃取法，并对其测定结果进行了统计分析，S-CO2萃取法用于全脂奶粉和营养奶粉总脂肪的测定，其浸提率分别为97．4％和98．4％。另外，S-CO2法萃取的总脂肪中主要脂肪酸种类及其含量与碱性乙醚萃取法相近。     

四种桉树青枯菌DNA提取方法及PCR检测灵敏度比较

以带有青枯菌Ralstonia solanacearum的桉树组织为材料,采用4种不同的提取方法抽提青枯菌DNA,同时利用青枯菌的特异性引物进行PCR扩增,比较了4种DNA的提取方法及PCR检测的灵敏度。结果表明,煮沸法和热裂解法操作相对简单,但检测灵敏度较低,检测限分别为104CFU/mL和103CFU/mL;简化提取法和试剂盒法检测效果较好,均可检测到102CFU/mL的青枯菌;简化提取法比试剂盒法操作更简单,检测成本低,具有更高的应用价值。     

一种适合杨树RNA提取的方法

本试验为三种杨树材料建立了一种杨树RNA提取的方法。本方法具有充分抑制材料中的多酚褐化,提高RNA产率;最大限度地去除多糖及次生代谢物质,避免与RNA共沉淀;去除蛋白质和DNA污染;提取时间短,质量高等特点。通过本方法提取的RNA OD260/OD280值在1.9~2.0之间,能够完全满足后续实验的要求,如体外翻译、cDNA文库构建、基因芯片和DDRT-PCR等。     

橄榄多酚的提取研究

利用溶剂浸提法、超声波辅助提取法和微波辅助提取法对橄榄中的多酚物质进行提取研究,并比较了3种方法的提取效果。结果表明:以1g橄榄果肉粉为原料,60%~70%丙酮水溶液是提取橄榄多酚的最适溶剂,最佳提取时间1h,温度20~30℃,固液比1∶20(g∶mL);超声波提取的最适功率为80W,最佳提取时间25min;微波提取的最适功率为280W,提取时间5s。3种提取方法的多酚提取得率分别为17.1%、19.3%和20.3%,与溶剂浸提法相比,超声波法和微波法提取时间短、效率高,提取效果明显优于前者,并且三者提取物的UV和HPLC检测图谱完全一致。     

一种适于提取复烤烟叶DNA的方法

以改良CTAB法提取复烤烟叶DNA，经U－3000紫外分光光度计测定，所获DNA呈典型的吸收曲线，且OD260／OD280在1．7－1．9之间；对烟草叶绿体不编码序列进行PCR扩增，获得理想条带。     

Supercritical fluid extraction of sapogenins from tubers of Smilax china

Supercritical CO(2) fluid extraction (SFE-CO(2)) was used to extract the sapogenins after acid hydrolysis from Smilax china tubers. The influence of extraction variables, such as modifier, pressure, temperature and extraction time, were studied. SFE-CO(2) was found to produce higher yield than conventional solvent extraction. The highest yield (0.454%) of sapogenins, mostly containing diosgenin, was obtained using 35 MPa pressure, 65 degrees C and 95% EtOH as a modifier for 180 min, higher than that obtained with conventional extraction methods (0.385%).     

Assessing raindrop impact energy at the forest floor in a mature Japanese cypress plantation using continuous raindrop-sizing instruments

The raindrop size distribution of throughfall and open rainfall was monitored continuously during a rainfall event using laser raindrop-sizing instruments (LD gauges), in order to calculate the raindrop impact energy in a plantation of mature Japanese cypress (Chamaecyparis obtusa), where surface erosion at the forest floor had been a problem. Data from two rainfall events were analyzed. The LD gauges recorded qualitative raindrop size distribution, and the capture rate during each rainfall event was used to manipulate raindrop data quantitatively. Throughfall and open rainfall comparisons revealed several important differences. First, throughfall raindrops were fewer in number and larger in size than open rainfall drops. In one rainfall event, for example, throughfall raindrops were less than one-fifth as frequent as open rainfall raindrops; in addition, the maximum throughfall raindrop diameter was 6.35mm compared to 3.31mm for open rainfall raindrops. Second, throughfall raindrops that were larger than the largest open rainfall raindrops comprised 63.8% of the throughfall precipitation by volume. Third, total raindrop impact energy from throughfall was over twice that of open rainfall. Moreover, comparison of throughfall events implied that throughfall raindrops did not always have a uniform distribution between different events or among different periods of time in one rainfall event, in contrast to findings in previous studies which showed that throughfall raindrops had a uniform size distribution independent of rainfall intensity. It is possible that an abrupt transition of throughfall intensity from low to high changes the distribution of throughfall raindrops.