磷对海水胁迫下芦荟幼苗离子分布的影响

研究了磷对海水胁迫下库拉索芦荟(A loe vera)幼苗干物质积累、植株含水量、在器官和组织水平上离子分布的影响。增磷显著缓解海水胁迫对芦荟生长的抑制,明显提高海水胁迫下芦荟幼苗的干物质积累和含水量。器官离子含量和X射线微区分析结果都表明,30%浓度海水胁迫下,外源磷水平的提高能显著降低芦荟幼苗根系N a 、C l-的吸收,增强K 、C a2 向地上部的运输和分配,从而维持叶片较高的K /N a 、C a2 /N a 比率,而这很可能是增磷提高芦荟对海水胁迫抗性的主要原因之一。     

弗氏志贺菌毒力大质粒导入大肠杆菌MG1655

目的:将弗氏2a志贺菌2457T的毒力大质粒pSF导入大肠杆菌MG1655。方法:通过诱动转移技术,将弗氏2a志贺菌2457T的毒力大质粒导入大肠杆菌MG1655。结果:构建了MG1655/pSF:pXL275-virG的毒力大质粒导入突变株,双向电泳初步比较分析表明在重组MG1655中有志贺菌毒力的表达。结论:成功地将弗氏2a志贺菌2457T毒力大质粒pSF导入了大肠杆菌MG1655。     

黑线姬鼠(Apodemus agrarius)的种群繁殖参数及其地理分异特征

黑线姬鼠（Apodemus agrarius）是我国广大地区的主要害鼠之一,是余庆县农田害鼠优势种,占总鼠数的94.81%。探讨其种群繁殖参数的变动规律及其地理分异特征,对其种群数量预测预报具有重要意义。通过对1987-2005年贵州省余庆县黑线姬鼠种群繁殖参数分析结果表明：研究期间共解剖标本5497只,其中,雌鼠2698只,雄鼠2799只,黑线姬鼠在当地1-11月份均可繁殖,主要繁殖期在3-10月份,每年4-5月份和8-9月份出现2次妊娠高峰。种群总性比（♀/♂）为0.96,多年平均怀孕率为36.91%±6.79%,平均胎仔数为5.33±1.07只,平均繁殖指数为0.81±0.17,平均睾丸下降率为59.13%±7.89%。不同年龄组种群繁殖力存在显著差异,随着种群年龄的增长繁殖力不断增加,成年Ⅰ组、成年Ⅱ组、老年组是种群繁殖的主体。种群繁殖参数不同年度之间比较稳定,不同月份、不同季节之间变化差异较大,具有明显的季节变化特征。年均种群密度与年均繁殖指数呈极显著正相关,与胎仔数显著正相关,与年均怀孕率、睾丸下降率、性比相关性不显著,繁殖指数是影响黑线姬鼠种群密度的重要因子。比较全国各地黑线姬鼠种群繁殖参数的地理分异特征认为,黑线姬鼠种群繁殖参数具有明显的地理分异现象,胎仔数、生殖强度由南向北逐渐增加,具有随纬度的升高趋向增加的特征;在高纬度地区繁殖时间较短;性比与纬度、经度的变化关系密切;各繁殖参数与海拔的变化相关性不明显,可排除海拔因素的影响。     

模拟酸雨对油菜(Brassica napus L.)生长、产量及品质的影响

以油菜为供试材料,通过田间试验方法研究了酸雨对农作物生长、产量及品质的胁迫效应.研究结果表明,模拟酸雨胁迫对油菜的生长发育有较大的影响,具体表现为株高、叶面积生长受抑,叶单面鲜重明显降低,且在pH3.1时开始出现外观上的可见伤害;产量的分析结果表明,pH4.1可作为酸雨对油菜产量的影响阈限;品质特征指标分析结果表明,酸雨胁迫会导致油菜粗脂肪含量降低,使可溶性糖含量减少,而且随着酸度增强,粗脂肪与可溶性糖降低幅度越大;酸雨胁迫对可溶性蛋白质的影响阈限在pH5.1与pH4.1之间,对游离氨基酸总量的影响阈限在pH4.1与pH3.1之间,而对还原性糖、总酸度的影响阈限则在pH3.1与pHl.5之间,但以上各指标的确切阈值及酸雨对其影响的具体机理还有待进一步研究.     

稻田甲烷排放模型研究——模型的验证

模型的有效性检验是模型应用于估计区域尺度稻田甲烷排放量的基本前提 ,尤其是针对多种不同的土壤、气候以及农业管理方式等可能影响稻田甲烷排放的环境条件下的模型检验。利用覆盖全国主要水稻产区的 94个甲烷排放观测案例对稻田甲烷排放模型 (CH4 MOD)进行了验证。这些观测区域分布范围北至北京 (4 0°30′N,116°2 5′E) ,南至广州 (2 3°0 8′N,113°2 0′E) ,东起杭州 (30°19′N,12 0°12′E) ,西到四川的土主 (2 9°4 0′N,10 3°5 0′E)。既有双季稻 ,也有单季稻 ,稻田灌溉及施肥方式也多种多样 ,对我国水稻生产具有较广泛的代表性。观测获得的稻田甲烷排放季节总量从 3.1kg C/hm2到 76 1.7kg C/hm2 ,平均值为199.4 (± 187.3) kg C/hm2 ;相应的模拟值分别为 13.9、82 4 .3和 2 2 4 .6 (± 187.0 ) kg C/hm2。模拟值与实测值的线性相关系数(r2 )为 0 .84 (n=94 ,p<0 .0 0 1)。CH4 MOD模型能够通过较少的输入参数有效地模拟我国主要农作方式下的稻田甲烷排放     

基于模型和GIS技术的中国稻田甲烷排放估计

将一个比较成熟的稻田甲烷排放模型CH4MOD和GIS空间化数据库结合,模拟估计了中国大陆2000年水稻生长季稻田甲烷的排放。模型的空间输入参数包括:逐日气温、耕层土壤砂粒含量、外源有机质施用量、稻田水分管理模式、水稻移栽期与收获期、水稻种植面积与单产,空间分辨率为10km×10km。模拟结果表明:2000年稻田甲烷排放量为6.02Tg,其中:早稻生长季排放1.63Tg、晚稻1.46Tg、单季稻2.93Tg。提高区域稻田甲烷排放估计精度的进一步目标应放在减小输入参数误差和提高空间数据精度上,在现有数据库基础和模型———GIS技术下探讨我国稻田甲烷排放估计的不确定性范围是必要的。     

Estimates of methane emissions from Chinese rice paddies by linking a model to GIS database

Methane is one of the principal greenhouse gases. Irrigated rice paddies are recognized as contributing to atmospheric methane concentration. Methane emissions from rice paddies are among the most uncertain estimates in rice-growing countries. Efforts have been made over the last decade to estimate CH₄ emissions from Chinese rice paddies via the model method. However, these estimates are very vague due to different models and upscaling methods. A reduction in these uncertainties may be achieved by coupling field-scale models with regional databases. The objective of this article is to develop a methodology of coupling a CH₄ emission model with regional databases by which CH₄ emissions from Chinese rice paddies can then be estimated. CH4MOD, a model for simulating CH₄ emissions from rice paddies with minimal input by using commonly available parameters, is of great potential in terms of upscaling as it has provided a realistic estimate of the observed results from various soils, climates and agricultural practices. By linking spatial databases to CH4MOD, CH₄ emissions from Chinese rice paddies in the 2000 rice-growing season were simulated on a day-by-day basis. The spatial databases were created by GIS with a spatial resolution of 10km10km, including soil sand percentage, amounts of crop straw and roots from the previous season and farm manure, the water management pattern, dates of rice transplanting and harvesting, acreage of rice planted, rice grain yield and daily air temperature. ARCGIS software was used to meet all GIS needs, including data access, projection definition, overlaying of different vector layers, creation of grids (a raster format of ARCGIS software) by converting vector data, and the data conversion between grids and ASCII formats. Methane emissions from rice paddies in mainland China in the 2000 rice-growing season were estimated to be 6.02 Tg (1 Tg = 10⁹ kg). Of the total, approximately 49% (2.93Tg) is emitted during the single rice-growing season, and 27% (1.63Tg) and 24% (1.46Tg) are from the early and late rice-growing seasons respectively. It was concluded that regional CH4 emissions from rice paddies could be estimated by coupling CH4MOD with regional databases with a high spatial resolution. A further effort should be made to improve the quality of the spatial databases, especially in terms of the amount of added organic matter and the water regime. It is also necessary to evaluate the uncertainties of the present estimates in order to improve the overall accuracy.     

稻田甲烷排放模型研究——模型及其修正

在过去十多年内 ,关于稻田甲烷排放的模拟已经进行了不少有益的探索并且开发出了数个有关的模型。模型的成功研制是准确定量估计不同区域范围内稻田甲烷排放的前提。以往大部分模型由于模拟精度不高 ,或者是其要求太多的输入参数 ,因而限制了它在大尺度范围内的广泛应用。在一个比较成熟的模型基础上 ,进行了必要的修正与扩充。增加了稻田甲烷通过气泡方式排放的模拟模块 ,并修正了原模型中关于土壤氧化还原电位变化的模拟 ,使之能适应于多种稻田水管理方式。新修正的模型 (CH4 MOD)不仅保留了原模型输入参数较少和易于获得的优点 ,而且能适应多种水稻耕作方式 ,这为进一步利用模型技术准确估计大尺度区域稻田甲烷排放提供了一种新的科学方法