影响青花菜游离小孢子培养胚胎发生的因子

以13个青花菜品种为材料进行游离小孢子培养,探讨影响青花菜小孢子胚胎发生的因子。结果表明:基因型是影响青花菜小孢子培养胚状体发生的关键因子,13种基因型中有8种基因型能诱导产生胚状体,诱导率为61.5%;处于单核晚期至双核期的小孢子是诱导小孢子胚状体发生的最佳时期;在1/2 NLN培养基中添加适量的活性炭、6-BA、AgNO3和2,4-D有利于胚胎发生。4℃预处理24 h和32.5℃热激24 h有利于小孢子产生胚状体。     

毛竹林物种多样性对集约经营的响应模型

根据岛屿生物地理学理论及其物种-面积关系:S=cAz,构建数学生态模型,研究集约经营对毛竹林物种多样性的影响.得出两点:(1)竹林生物多样性对集约经营的响应具有一定的面积效应,即原粗放经营竹林的面积越大,物种减少幅度就越大,原竹林越小,物种减少幅度就越小;(2)毛竹林诱导扩张过程符合Logistic方程,随着时间的延长...     

基于农作制分区的1985—2015年中国小麦生产时空变化

Comparing spatio-temporal variation characteristics of China’s wheat production, yield, sown area and yield-area-contribution in different farming zones in the past 30 years could help improving wheat planting layout and adjusting planting structure. Concentration index, rate of change, moving of gravity and resolution of yield-area-contribution were used to analyze spatio-temporal changes of China’s wheat production and yield-area-contribution based on county wheat production statistics including sown area, production and yield from 1985 to 2015. The wheat sown area decreased obviously in Northeast farming region, Northwest farming region and South farming region and increased rapidly in Huang-Huai-Hai farming region and Yangtze Plain farming region. In Huang-Huai-Hai farming region, the concentration indexes of Haihe Plain farming region, Huang-huai Plain farming region and Fenwei Basin farming region reached to 20.64%, 25.77%, and 21.65% respectively in 2015. Wheat production increased significantly by more than 48 milliontons in Huang-Huai-Hai farming region, and nearly 8 million tons Yangtze Plain farming region but decreased by more than 2.6 million tons in Northeast farming region. In Huang-Huai-Hai farming region, wheat production was concentrated in Haihe Plain farming region, Huang-huai Plain farming region and Yuxi Hill farming region. The average wheat yield continuously improved during the study period, Huang-Huai-Hai farming region and Northwest farming region had the yield increase up to 103.5 kg hm ^-2 and 92.9 kg hm ^-2 each year. Wheat yield in Yuxi Hill farming region, Fenwei Basin farming region and Haihe Plain farming region was relatively high in Huang-Huai-Hai farming region. The yield-reduced area was mainly caused by the decreasing of sown area, while the yield-area-contribution rate was different in yield-increased area. Yield-dominant counties were reduced, area-dominant counties were increased and yield-area-dominant counties were relatively steady. In production increased area, yield-dominant and yield-area-dominant counties were the main types in Huang-Huai-Hai Farming region, area-dominant and yield-area-dominant counties were the main types in Yangtze Plain farming region. Chinese wheat production was increasingly concentrated in Huang-Huai-Hai farming region which has high and rapid increase of wheat yield over the past three decades. Haihe Plain farming region, Huang-huai Plain farming region and Fenwei Basin farming region were the most concentrated areas in Huang-Huai-Hai farming region for wheat production during this period. Wheat yield and sown area jointly promoted the increase of wheat production in Huang-Huai-Hai farming region, wheat sown area was the crucial factor to increase wheat production in Yangtze Plain farming region, especially in the north of Jiangsu, Anhui province and greater part of Xinjiang.     

能产生多角体的可线性化杆状病毒的构建

【目的】改进用于同源重组研究的制备杆状病毒DNA的方法。【方法】采用PCR方法从BmNPV中扩增出多角体基因,并在其两端引入Bsu36 I酶切位点。将此片段克隆入转移载体pBacPAK8中,与线性化的杆状病毒DNA共转染昆虫细胞,获得重组病毒。该病毒能形成多角体,便于纯化,同时可以被 Bsu36 I酶切。该重组病毒的多角体纯化后被裂解,并提取病毒DNA。病毒DNA经Bsu36 I酶切后,与含gfp基因的转移质粒共转染家蚕BmN细胞,在荧光显微镜下观察重组病毒的转染效率。【结果】BmNPV多角体基因克隆入转移载体pBacPAK8中后,与线性化的AcPak6及BmPak6 DNA共转染sf细胞及BmN细胞,均能产生大量的多角体。获得的重组病毒DNA经酶切后,进一步与含gfp基因的转移质粒共转染的实验表明,这种改造后的重组病毒仍具有较高的转染重组率。【结论】本实验成功地对用于同源重组的杆状病毒DNA进行了改进,简化了病毒DNA的纯化方法,并且重组效率较高。     

基于Copula函数的河川径流丰枯遭遇分析

【目的】研究两变量联合概率的分布问题,探讨干支流的丰枯遭遇分析方法。【方法】采用Copula函数,构建了渭河干流及其支流千河年径流的联合概率分布模型,对干支流的丰枯遭遇进行分析,并绘制了干支流联合分布等值线图。【结果】宝鸡市渭河干流年径流量的边际分布服从皮尔逊Ⅲ型分布,而支流千河年径流量的边际分布服从对数正态分布,且干支流同时出现丰水年的概率大于同时出现平、枯水年的概率。【结论】用Copula法描述干支流的丰枯遭遇问题具有可行性。     

南美斑潜蝇对寄主植物挥发物的行为反应

植食性昆虫通常利用寄主植物释放的挥发性物质寻找食物和产卵场所,植物也可利用其挥发物对前来取食和产卵的昆虫产生趋避作用.本文采用"Y"型嗅觉仪,测定了菜豆、黄瓜、南瓜和番茄等4种寄主植物挥发物对南美斑潜蝇成虫的引诱作用.结果表明,所有供试寄主植物的健康植株和受害植株均对南美斑潜蝇成虫具有明显的引诱作用,其中菜豆的引诱力最强,番茄最差.说明寄主植物挥发物在南美斑潜蝇成虫选择寄主植物过程中起着重要的作用.     

The Avalon explosion: evolution of Ediacara morphospace

Ediacara fossils [575 to 542 million years ago (Ma)] represent Earth's oldest known complex macroscopic life forms, but their morphological history is poorly understood. A comprehensive quantitative analysis of these fossils indicates that the oldest Ediacara assemblage-the Avalon assemblage (575 to 565 Ma)-already encompassed the full range of Ediacara morphospace. A comparable morphospace range was occupied by the subsequent White Sea (560 to 550 Ma) and Nama (550 to 542 Ma) assemblages, although it was populated differently. In contrast, taxonomic richness increased in the White Sea assemblage and declined in the Nama assemblage. These diversity changes, occurring while morphospace range remained relatively constant, led to inverse shifts in morphological variance. The Avalon morphospace expansion mirrors the Cambrian explosion, and both events may reflect similar underlying mechanisms.     

农杆菌介导的pac1基因转化大豆研究

选用高感大豆花叶病毒病而再生能力较强的大豆品种和品系作为受体,对丛生芽诱导培养基、侵染菌液的制备以及根的诱导方法进行了优化。采用优化后的遗传转化体系以农杆菌介导法将pac1导入大豆,MSB培养基中附加2 mg/L6-BA+0.2 mg/LIBA进行丛生芽诱导,液体YEB重悬活化菌体后侵染,MSB培养基中蔗糖含量15%+2 mg/LIBA+0.2 mg/L6-BA进行生根诱导。共获得8株PCR检测呈阳性植株,经SouthernBlot检测,证明pac1基因已整合到大豆基因组中。转基因植株对病毒的抗性评价正在进行中。     

植物内生菌的研究进展

植物内生菌生物学特性、动力学规律、群落生态组成,目前已成为国内外学者研究的热点。随着其研究领域的不断拓宽和研究方法的不断深入,植物内生菌在科研、农业生物防治、医疗卫生等领域中的应用越来越广泛。本文介绍了植物内生菌的发现过程和定义,概述了其生物多样性、动力学、研究方法、在农业和医药上的应用等方面的研究进展,并探讨了该研究领域中存在的一些问题。     

不同生态恢复措施对宁夏黄土丘陵区典型草原蒸散特征的影响

为了探讨黄土丘陵区不同生态恢复措施对典型草原蒸散特征的影响,通过野外测定,研究了水平沟、鱼鳞坑和封育3种恢复措施下草原的蒸散特征,发现棵间蒸发量在各措施下差异不显著。当地5种主要牧草---长芒草（Stipa bungeana）、糙隐子草（Cleistogenes squarrosa）、冷蒿（Artemisia frigida）、达乌里胡枝子（Lespedeza davurica）和铁杆蒿（Artemisia sacrorum）的平均蒸腾速率在水平沟措施下最大,封育草地次之,鱼鳞坑最低。棵间蒸发量与地上20 cm处气温和0~40 cm土壤含水率明显正相关,蒸腾速率与土壤0~15 cm温度和0~40 cm含水率呈明显正相关。