慢生大豆根瘤菌(Bradyrhizobiumjaponicum)聚羟丁酸合成酶基因(phbC)的克隆和序列测定

以苜蓿根瘤菌Rm10 2 1的 phaC基因突变体菌株Rm1114 4 (phaC ::Tn5 - 2 33)为受体菌 ,通过功能互补 ,成功地从构建的Bradyrhizobium japonicum USDA110基因文库中 ,筛查到能与Rm1114 4互补 ,使之恢复在以乙酰乙酸为唯一碳源的M9培养基 (M9-AA)平板上 5d形成明显可见菌落 ,以及在MOPS平板上形成粘液型菌落的表型的重组粘粒 pDC2 ;经证实 ,该粘粒带有 phbC基因 .完成了该基因的全序列测定并已在GenBank登记 ,登记号为AY0 775 80 .B .japonicumphbC基因由 180 3碱基对组成 ,GC含量 6 1.8% ,AT含量 38.2 % ;编码 6 0 0个氨基酸 ,Mr=6 6 .95× 10 3 .图 3表 3参 13

葡萄卷叶病毒RT-PCR检测技术

为调查葡萄植株携带葡萄卷叶病毒(GLRaV)的情况,以带毒和非带毒指示植物“品丽珠”为试验材料提取总RNA,并以此总RNA为模板进行RT-PCR扩增,建立了GLRaV的RT-PCR检测体系,并对GLRaV cDNA序列进行测定,结果成功地检测到了GLRaV。经多次试验证明,该检测结果准确可靠,可以用于GLRaV的检测。

沈阳市郊耕地不同土属交换态钙镁铁锰铜锌含量状况的分析

对沈阳市郊区 1994个耕地土壤样本 (0cm～ 2 0cm)的交换态钙、镁、铁、锰、铜、锌含量分布的研究结果表明 :不同土属交换态钙、镁、铁、锰、铜、锌含量存在较大差异。碳酸盐草甸土含钙 ,壤质草甸土含镁 ,风沙土、水稻土、草甸土含铁 ,碱化草甸土含锰 ,菜园土和水稻土含铜 ,菜园土含锌较高 ;棕壤含钙 ,碳酸盐草甸土含铁、锰、铜、锌 ,水稻土含锌普遍较低。造成这种差异的原因既有成土母质、成土过程、土壤质地等结构性因素 ,又有耕作、施肥和环境污染等随机性因素。比较不同土属交换态营养元素含量 ,可以更好地对土壤—作物系统的营养元素进行调控 ,指导中量、微量元素肥料施用。图 2 ,参 15。

沈阳市郊耕地土壤交换性Ca含量的空间异质性特征

利用地统计学和地理信息系统相结合的方法研究了沈阳市郊耕地土壤 (0～ 2 0cm)交换性钙含量的空间异质性特征 ,绘制了交换性钙含量的空间分布图。结果表明 ,土壤交换性钙含量经对数转换后基本符合正态分布 ,变异函数的最佳理论模型为球状模型 ,交换性钙含量具有很强的空间相关性 ,空间自相关距离为 15 8km ,其空间异质性主要受成土母质和土壤类型等结构性因子的影响

施用泥炭对风沙土改良及蔬菜生长的影响

通过盆栽试验比较了施用不同剂量的泥炭 (0 %、2 %、5 %、8%及 10 % )对风沙土改良的效果和对白菜生长及产量的影响。结果表明 ,泥炭能增强风沙土的持水能力 ,降低土壤的pH值 ,增加土壤中有机质、全氮、速效氮和速效磷等的含量 ;白菜根系长度、生物量、高生长和地上部分的生物量均有增加 ,其中 8%泥炭处理为最佳 ,其根系长度、根鲜重、干重、高生长、地上部分鲜重、干重依次比对照增加 71%、4 0 2 %、4 6 4 %、10 7%、84 7%和 10 0 1% ;同时施用泥炭还有利于提高白菜干物质的积累及其品质

塔克拉玛干沙漠腹地人工绿地土壤中微生物的生态分布及其与土壤因子间的关系

对咸水灌溉条件下的塔克拉玛干沙漠腹地人工绿地土壤微生物的分布规律和环境因子对土壤微生物分布的影响进行了研究 .结果表明 ,人工绿地建成后 ,土壤结构和养分状况得到改善 ,土壤微生物在时间和地域分布上呈现明显的规律性 .土壤微生物区系组成中 ,细菌占绝对优势 ,放线菌次之 ,真菌最少 ;表层微生物数量远多于下层土壤 ;林地外围距林缘近的土壤微生物数量较多 ,3m以外微生物数量已接近流沙微生物量 ;3类土壤微生物分布具有不同的季节性规律 ,且不同立地类型土壤微生物分布差异显著 .土壤速效磷、速效氮、全N对微生物的分布有较大的直接作用 ,通径系数为 1 .0 1～ 2 .58.速效磷 速效钾、有机质 速效钾、速效氮 速效钾、速效氮 效磷速、有机质 速效磷、速效磷 速效氮、全N 速效钾、速效钾 速效磷、全N 速效磷和含水量 速效氮之间的间接作用对微生物影响较明显 ,作用系数为 1 .37～ 2 .58,其余因素的作用相对不显著

透光分层疏透度测定及其在次生林结构研究中的应用

次生林是中国森林的主体 ,对其进行合理的经营无疑对中国天然林资源保护及国家生态安全建设具有重大意义 .次生林的结构 (尤其是垂直结构 )是该林种合理经营的重要因素 .本文在以往研究的基础上 ,引入了分层疏透度的概念 ,并以透光分层疏透度表征林分的垂直结构 ;详细介绍了应用全天照片测定透光分层疏透度的方法与步骤 ,分析了透光分层疏透度在次生林结构研究和次生林的经营理论与技术研究中的应用前景

土地处理技术在干旱-半干旱过渡带生态建设中的应用

土地处理系统是在干旱 -半干旱过渡区实现污水无害化、资源化的有效技术。内蒙古霍林河矿区污水土地处理系统设计与运行结果表明 ,该区具备推广土地处理技术的良好条件 ,土地处理系统应以慢速渗滤和污水资源利用型为主 ,实现污水处理与生态环境建设的结合。污水资源的利用有助于增加镶嵌型复合生态系统的稳定性 ,加速人工林的成林郁闭 ,增加林木蓄积量 ,改善干旱、半干旱地区的生态环境

土壤温度和水分对长白山不同森林类型土壤呼吸的影响

在实验室条件下 ,将不同含水量的 3种森林类型的土柱分别置于 0、5、1 5、2 5和 35℃条件下 ,进行土壤呼吸测定 .结果表明 ,在 0～ 35℃范围内 ,土壤呼吸速率与温度呈正相关 .在一定含水量范围内 (0 .2 1～ 0 .37kg·kg- 1 ) ,土壤呼吸随含水量的增加而升高 ,当含水量超出该范围 ,土壤呼吸速率则随含水量的变化而降低 .土壤温度和水分对土壤呼吸作用存在明显的交互作用 .不同森林类型土壤呼吸作用强弱存在显著差异 ,大小顺序为阔叶红松林 >岳桦林 >云冷杉暗针叶林 .阔叶红松林土壤呼吸作用的最佳条件是土壤温度 35℃、含水量 0 .37kg·kg- 1 ;云冷杉暗针叶林下的山地棕色针叶林土壤呼吸作用的最佳条件是 2 5℃、0 .2 1kg·kg- 1 ;岳桦林土壤呼吸作用的最佳条件是 35℃、含水量 0 .37kg·kg- 1 .但是 ,由于长白山阔叶红松林、云冷杉林和岳桦林处在不同的海拔带上 ,同期不同森林类型土壤温度各不相同 ,相差 4～ 5℃ ,所以野外所测的同期山地棕色针叶林土呼吸速率应低于暗棕色森林土呼吸速率 ,山地生草森林土呼吸速率应高于山地棕色针叶林土的呼吸速率

Expression of the lacZ reporter gene in sporophytes of the seaweed Laminaria japonica (Phaeophyceae) by gametophyte-targeted transformation

The seaweed Laminaria japonica (Phaeophyceae) has a two-generation life cycle consisting of haploid gametophytes and diploid sporophytes. Female and/or male gametophytes were transformed using particle bombardment and the histological LacZ assay was performed on sporophytes generated by either parthenogenesis or inbreeding. Female gametophyte-targeted transformation resulted in similar lower efficiencies in both parthenogenetic and zygotic sporophytes, and only a chimeric expression pattern was observed. Male gametophyte-targeted transformation led to a higher efficiency, with 3.5% of the zygotic sporophytes stained completely blue (all-blue), implying the integration of lacZ at the one-cell stage. Polymerase chain reaction analysis using primers specific for a lacZ-vector juncture fragment and subsequent blotting indicated the presence of the introduced gene in the sporophytes. The method reported here has a potential for seaweed transformation using spore-based bombardment followed by the developmental process.

Observations on the nocturnal activity and feeding behavior of Anguilla japonica glass eels under laboratory conditions

Glass eels of the temperate anguillid species, Anguilla japonica, clearly showed a nocturnal activity rhythm under laboratory conditions. Light-dark cycle was a determinant factor affecting their photonegative behavior, nocturnal locomotor activity, and feeding behavior. Under natural light conditions, glass eels remained in shelters with little daytime feeding, but came out to forage during darkness. They moved and foraged actively in the following dark, and then their activity gradually declined possibly because of food satiation. They finally buried in the sand or stayed in tubes immediately after the lights came on. Under constant light, glass eels often came out of the shelters to forage in the lights but spent little time moving outside the shelters (e.g. swimming or crawling on the sand). Glass eels took shelter to avoid light and preferred tubes to sand for shelter possibly because tubes were much easier for them to take refuge in than sand. Feeding and locomotor activities of the glass eels were nocturnal and well synchronized. They appeared to depend on olfaction rather than vision to detect and capture prey in darkness. Feeding was the driving force for glass eels to come out of sand under constant light. However, in the dark, some glass eels swam or crept actively on sand even when they were fully fed. The lunar cycles of activity rhythms of glass eels that have been observed in some estuarine areas were not detected under these laboratory conditions.

A new poly brominated dibenzylphenol from Rhodomela confervoides

A new poly brominated dibenzylphenol named as rhodomevoidin was isolated from Rhodomela confervoides. Its structrue was elucidated as 3-bromo-4, 5-bis (2, 3-dibromo-4, 5-dihydroxybenzyI)pyrocatechol by spectroscopic methods including IR, HRFABMS, 1D and 2D NMR techniques.

In vivo antioxidant activity of polysaccharide fraction from Porphyra haitanesis (Rhodephyta) in aging mice

Sulfated polysaccharide fraction F2 from Porphyra haitanesis (Rhodephyta) showed inhibitory effect on the in vitro lipid peroxidation. In the present study, the age-related changes in the antioxidant enzyme activity, lipid peroxidation, and total antioxidant capacity (TAOC) in different organs in mice were investigated and the in vivo antioxidant effect of F2 in aging mice was checked. Increased endogenous lipid peroxidation and decreased TAOC were observed in aging mice. Intraperitoneal administration of F2 significantly decreased the lipid peroxidation in a dose-dependent manner. F2 treatment increased TAOC and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in all the organs tested in aging mice. It is concluded that the sulfated polysaccharide fraction F2 can be used in compensating the decline in TAOC and the activities of antioxidant enzymes and thereby reduces the risks of lipid peroxidation. (C) 2003 Elsevier Science Ltd. All rights reserved.