红景天属植物的研究进展

综述了红景天的主要化学组成,生理功能及用途,论述了不同产地不同品种红景天中红景天苷、酪醇、肉桂醇苷的含量,及红景天提取物的制备工艺和检测方法.     

Comparison of field sampling methods for assessing coarse woody debris and use of airborne laser scanning as auxiliary information

Coarse woody debris (CWD) has been recognized as one of the strongest indicators of forest biodiversity and its assessment has been emphasized in the development of new inventory methods. In this study, the most commonly referenced probability sampling methods were tested in a field area of 305.8 ha to gain comparative information on their performance and efficiency. Simple random sampling (SRS), systematic sampling and cluster sampling with fixed sized circular sample plots were tested, as well as strip sampling, transect relascope sampling and adaptive cluster sampling (ACS). Point relascope sampling and line intersect sampling were also tested for inventories of downed dead wood volumes. In addition, the amount of standing dead wood was assessed by means of traditional small angle relascope sampling. In general, the use of additional information in the inventory process has shown promising results. A new method for using data derived from airborne laser scanning (ALS) as a source of auxiliary information in the assessment of CWD volumes is presented, using probability proportional to size (PPS) sampling for the selection of the first-stage sample units in ACS (ACS_PPS) and for the placement of fixed sized plots (PLOT_PPS). The sampling methods were compared in terms of the cost-effectiveness. Point relascope sampling proved the most efficient sampling method for inventorying CWD volumes. PLOT_PPS and ACS_PPS were more efficient than the inventory of fixed sized plots (PLOT_SRS) and ACS (ACS_SRS) where sample units were selected with SRS. However, these methods could not achieve the same efficiency as relascope samplings. Nevertheless, the use of probability layers derived from ALS data gave promising results and offers new possibilities for inventorying CWD volumes more efficiently.     

正负刚度并联弹簧汽车座椅悬架设计与仿真

介绍正负刚度并联相消原理,通过分析可知应用该原理可以有效降低系统的固有频率,减小隔振传递率。基于该原理选用连杆弹簧负刚度机构与正刚度弹簧并联,设计新型汽车座椅隔振系统,给出该隔振系统的结构参数和性能参数,得到符合座椅要求的固有频率。用ADAMS建立座椅悬架以及人体-座椅五自由度的虚拟样机模型,采用正弦激励模拟汽车驾驶室地板的输入激励进行仿真,在同样的激励条件下,对未加负刚度的座椅隔振系统进行同样的仿真,分别得到人体头部、躯干上部、躯干下部、臀部和座椅振动的加速度谱。结果表明,与未施加负刚度的普通座椅隔振系统相比,人体加速度明显减小,舒适度得到有效改善。     

苏北地区草履蚧的发生规律及防治技术

通过对苏北地区草履蚧发生规律和危害特点的观察研究,对草履蚧的防治应采取综合防治措施。防治方法主要有:农业防治、化学防治和天敌防治,另外,要加强检疫。     

从松脂中分离左旋海松酸的新工艺研究

探讨了以乙酸乙酯替代丙酮为溶剂,从松脂中分离左旋海松酸的新工艺。结果表明,在乙酸乙酯中,松脂树脂酸与丁醇胺反应,生成粒径大、粘度小、易于转移、过滤和洗涤的聚针晶形胺盐沉淀;减压过滤得到的胺盐粗产物具有溶剂残留量少、色泽浅、分散性好的特点,仅用95%乙醇重结晶提纯2次,就可获得纯度为95%的左旋海松酸胺盐;左旋海松酸胺盐和左旋海松酸的得率高于以丙酮为溶剂的传统工艺。     

油茶叶枯病菌的生物学特性

近几年.油茶叶枯病已从油茶的次要病害上升为主要病害.为给此病害的防治提供依据,对该病菌的生物学特性进行了分析,分离纯化了油茶叶枯病原菌,并对影响其生长的温度、酸碱度、光照和培养基进行了试验研究.结果表明:病原菌在5～31℃之间均能生长,其中27℃的温度为菌丝生长的最适宜温度;病原菌在pH值为4～9之间均可以生长,当pH值为6时菌丝生长最快;光照对菌丝生长的影响不大;以蔗糖为碳源的培养基最适合该病菌的生长,以葡萄糖为碳源的培养基其生长最慢.     

四种因素对“龙薯3号”秋薯产量及产量构成的影响

对秋薯“龙薯3号”进行了栽插密度、施氮量、施钾量及氮肥施用法四因素正交高产试验,结果表明,组合3（A1B3C3D3）,即每666.7m2插植3000株,施氮12kg,施钾18kg,氮肥施法采用前多后少为最优组合,小区平均产量最高达68.4kg;其次为组合7（A3B1C3D2）,即每666.7m2插植4000株,施氮8kg,施钾18kg,氮肥施法采用等量分施,小区平均产量达65.2kg。施钾量对产量的影响最大,其次是栽插密度和施氮量,氮肥施用法的影响最小。另外就不同种植密度对产量结构的影响作了简要分析。     

雄配子体选择在遗传偏分离中的效应分析

偏分离是一种广泛存在于生物中的遗传学现象,被认为是一种强有力的进化动力。本文从生殖隔离因子、细胞质效应以及环境因素三个方面分析了雄配子体选择可能导致的遗传偏分离效应。研究证明,位于细胞核基因组上的生殖隔离因子如配子体基因、不育基因等遗传因素导致的雄配子体选择是引起遗传偏分离的主要原因;而细胞质核互作导致的雄性不育产生的雄配子选择同样可导致核基因发生遗传偏分离;非遗传因素如环境温度等引起的雄配子选择也会导致遗传偏分离现象。     

浅析区域生态环境质量评价

区域生态环境是一个开放的巨系统。由于生态环境质量评价是一项系统的研究工程,本文将从区域生态环境的内涵、指标体系和评价方法三方面的研究成果做出系统的阐述,最后探讨区域生态环境质量评价中出现的新趋势。     

一株脱氧雪腐镰刀菌烯醇转化菌的分离、鉴定及其转化效果研究

以脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)为唯一碳源,通过富集培养从土壤中分离到一株可以转化DON的真菌,命名为NJA-1.用引物Bt2a、Bt2b扩增了该菌的β-tubulin基因序列,GenBank的登录号为DQ902579.通过基因序列分析和形态学观察最终鉴定该菌株为塔宾曲霉(Aspergillus tubingensis).该菌与塔宾曲霉AY820009的同源性为99%.在pH 60、30 ℃、14 d内其对DON的平均转化率为944%.HPLC-MS分析结果表明,DON转化产物的相对分子质量为3144,比DON的相对分子质量(2963)增加了181.该菌在无机盐培养基中对DON的最高耐受浓度为40 mg·L-1.提示:该菌可用于DON的生物转化.