低磷胁迫下光质对番茄幼苗生长及生理抗性的影响

为研究低磷胁迫下不同光质对番茄幼苗生长及生理抗性的影响,以番茄品种‘中杂9号’为试材,采用水培法,设置2种不同光质(蓝紫光、白光)与3个磷素水平(0.22、0.44、0.66 mmol/L)共6个组合处理。结果表明,与正常供磷水平相比,轻度、重度低磷胁迫下番茄叶绿素含量、叶片相对含水量、生物量均显著降低,总根长、丙二醛含量、超氧化物歧化酶、过氧化物酶、过氧化氢酶活性和可溶性糖、可溶性蛋白、脯氨酸含量均显著增加。同时,低磷胁迫下,相较于白光处理,蓝紫光处理明显增加了番茄幼苗叶绿素含量、叶片相对含水量、总根长、总表面积、平均直径;同时降低了叶片和根系中的MDA含量,提高了可溶性糖、可溶性蛋白、脯氨酸含量和抗氧化酶活性,进而促进了植株生物量的积累。综上,蓝紫光处理能够增强番茄植株对低磷胁迫的适应能力。     

户外LED广告屏色光侵扰问题调查研究

近年来LED广告屏在城市中广泛使用,但居住区周围布置的LED广告屏在夜间对居民形成了强烈的色光侵扰。为了明确LED广告屏形成的色光侵扰程度及其防控措施,以北京、天津地区17处LED广告屏及受其侵扰的居住建筑为研究对象,展开主观问卷调查,并现场测试LED广告屏侵扰光的色坐标、亮度等参数,获得187份调查问卷及288组测试数据。通过对比分析主观问卷和测试数据,明确了LED广告屏的主要侵扰因素为LED屏与居住建筑的相对位置关系、LED屏侵扰光亮度水平及其数值变化和LED屏的光色交替变化,提取了各侵扰色光的波长及亮度数值范围,提出了对LED屏幕设置的建议。     

北疆地区阿克达拉灌区土壤成因和特性特征分析

针对新疆“沙漠绿洲灌溉农业”这一典型特点,灌区建设在北疆地区农牧业发展中具有重要作用,而灌区土壤条件作为灌区立足的根本具有举足轻重的地位,因而正确地对灌区土壤成因及土壤肥力做出评价,才能保证灌区土壤水土资源的合理开发利用和实现农牧业可持续发展。以新疆阿勒泰地区阿克达拉灌区作为研究对象,通过对灌区土壤现状的调查、资料收集、样品采集及室内化验分析,分析研究了灌区内土壤形成因素、分布以及不同类型土壤的特征特性。研究表明,灌区内土壤形成条件主要是自然因素中的冰冻作用、风力作用和温差变化作用,灌区主要分布有荒漠淡棕钙土和风沙土。风砂土质地为含土粉砂砾层-粉细质沙土,成土母质为运距离搬运的风沙为主;荒漠淡棕钙土质地为中细砂,且中细砂含量从坡上部至下部具有规律性,成土母质系为三系砂质、泥岩风化后被洪水携带或原地残留,且近代以来该区域沙化趋严重。研究成果为阿克达拉灌区和北疆类似灌区进一步开发区域内水土资源理论基础和技术依据。     

阔叶林下人工更新红松幼树光合作用研究

利用LI-6400便携式光合测定系统,对天然次生林下、林缘、林窗环境中红松幼树的净光合速率进行测定,同时记录光合生理因子和环境因子。分析了林下、林缘、林窗不同条件下红松幼树的净光合速率、蒸腾速率、光能利用率、水分利用率日进程及其差异。结果表明：日平均气温林下〈林缘〈林窗;空气相对湿度林下〉林缘〉林窗;林窗阳面叶光合有效辐射呈单峰型曲线,阳面叶光合有效辐射最大值林窗〉林缘〉林下;红松幼树净光合速率阳面叶大于阴面叶,林窗处阳面叶净光合速率日变化呈单峰型曲线,林缘呈双峰型曲线,林下呈多峰型曲线,净光合速率最大值林窗〉林缘〉林下;红松阳面叶的光能利用率林下〉林缘〉林窗;红松阳面叶蒸腾速率日变化呈单峰型曲线,且蒸腾速率林窗〉林缘〉林下,阳面叶〉阴面叶;红松阳面叶水分利用率林下〉林窗〉林缘,阳面叶水分利用率〉阴面叶水分利用率。     

沱江流域马尾松、湿地松人工林小气候比较

比较了沱江流域低山区马尾松和湿地松人工林在小气候因子上的差异。结果表明,湿地松林内夜间气温高于马尾松林,而午后气温则低于马尾松林;湿地松林内的相对湿度高于马尾松林,而风速则低于马尾松林;湿地松林内的月均土壤表面温度低于马尾松林;距地面0.5 m高处的光照强度和风速在2种人工针叶林中无明显差异,但在距地面2 m高处却是马尾松林高于湿地松林。2种人工针叶林内小气候因子的差异主要与2种林分的林冠郁闭度有关。     

猪肺泡巨噬细胞感染PRRSV进程中差异表达基因及基因功能富集分析

猪呼吸和繁殖综合症病毒（porcine reproductive and respiratory syndrome virus,PRRSV）感染猪后会引起妊娠母猪严重繁殖障碍和仔猪呼吸困难及高死亡率,给养猪产业造成了巨大经济损失,因此挖掘PRRSV感染猪肺泡巨噬细胞进程中差异表达的基因及机理有重要意义。本研究对来自GEO数据库的PRRSV感染猪肺泡巨噬细胞sage表达谱数据GSE10346进行后续挖掘。先用sage软件处理,经sagemap注释得到上调已知基因49个,下调已知基因41个。利用AgBase网站上的GORetriever工具和GOSlim Viewer工具进行细胞组分（cellular component）、分子功能（molecular function）及参与的生物过程（biological process）分类后发现有4个基因与病毒的复制相关：其中IL8已有报道认为与抗PRRSV相关;TNF-α能够抑制PRRSV复制;PPIA可能与GP5蛋白胞外区中和决定簇与抗体发生作用的24位脯氨酸有关;ICAM-1在嗜中性粒细胞的产生中起关键作用,与病毒吸附相关。这4个基因与PRRSV的致病机制相关,可望用于抗PRRSV研究。进一步利用David在线工具进行基因功能富集分析后,发现几个免疫通路,如趋化因子通路,Toll-like受体信号通路和NOD-like受体信号通路具有检验显著性,这些免疫通路在PRRSV感染过程中起着一定作用,有望成为抗PRRSV的靶通路。     

Identification and characterization of rhizobacteria isolated by enrichment culture on spinach roots

Rhizobacteria can be used for biological control and environmental restoration. In this study, we performed enrichment culture of rhizobacteria, identified isolates, and investigated the physiological properties of the bacterial isolates. Five bacteria differing in their colony morphology were isolated from spinach roots as enriched rhizobacteria. Four isolates were identified by sequencing of 16S rDNA as β and γ-Proteobacteria; 16S rDNA sequencing was not completed on one isolate. Based on microscopic observation, we determined that at least two types of bacteria differing in their morphology co-existed in this isolate, and that it may not be possible to culture the two types separately. Based on tests of substrate utilization, we could not find the characteristics that were common to the isolates. One of the five isolates was inoculated into non-sterile soil, and we examined its root-colonizing ability. The test strain which was not detected in the non-rhizosphere soil, accounted for about 20% of the total bacteria on the roots. These results suggested that enrichment culture might be useful for isolating bacteria with a high root-colonizing ability     

不同光强下红蓝光配比对樱桃萝卜生长与产量的影响

采用LED光源在室内可控环境下设置3种光照强度（180、240、300μmol·m^-2·s^-1）和2种红蓝光配比（1R:1B、2R:1B）,以研究不同光强和红蓝光配比组合对樱桃萝卜真叶数、叶绿素含量、肉质根形态以及干鲜重的影响。结果表明,光强为180μmol·m^-2·s-1时,2R:1B处理的新叶叶绿素含量略高于1R:1B处理,但地上部鲜重却略低于1R:1B处理,其它生长指标不同光质处理间无显著差异。光强为240μmol·m^-2·s^-1时,相比1R:1B 处理,2R:1B处理显著提高了樱桃萝卜的新叶叶绿素含量、地上部干鲜重、根直径、根体积、肉质根干鲜重以及干鲜根冠比（P＜0.05）。光强300μmol·m^-2·s^-1时,2R:1B处理的新叶叶绿素含量略低于1R:1B处理,但地上部干鲜重显著高于1R:1B处理（P＜0.05）,其它指标无显著差异。相同红蓝光配比下,樱桃萝卜新叶叶绿素含量、根直径、根体积、肉质根干鲜重及根冠比均随着光强的增加而增加。地上部干鲜重随光强增加的变化因光质而异。总之,一定强度的LED红蓝光质是植物工厂樱桃萝卜高产的光环境基础,并且光强高于一定水平时适宜的红蓝光配比对其生长具有显著促进作用。     

Elevated CO2 stimulates N2O emissions in permanent grassland

To evaluate climate forcing under increasing atmospheric CO₂ concentrations, feedback effects on greenhouse gases such as nitrous oxide (N₂O) with a high global warming potential should be taken into account. This requires long-term N₂O flux measurements because responses to elevated CO₂ may vary throughout annual courses. Here, we present an almost 9 year long continuous N₂O flux data set from a free air carbon dioxide enrichment (FACE) study on an old, N-limited temperate grassland. Prior to the FACE start, N₂O emissions were not different between plots that were later under ambient (A) and elevated (E) CO₂ treatments, respectively. However, over the entire experimental period (May 1998–December 2006), N₂O emissions more than doubled under elevated CO₂ (0.90 vs. 2.07 kg N₂O-N ha⁻¹ y⁻¹ under A and E, respectively). The strongest stimulation occurred during vegetative growth periods in the summer when soil mineral N concentrations were low. This was surprising because based on literature we had expected the highest stimulation of N₂O emissions due to elevated CO₂ when mineral N concentrations were above background values (e.g. shortly after N application in spring). N₂O emissions under elevated CO₂ were moderately stimulated during late autumn–winter, including freeze–thaw cycles which occurred in the 8th winter of the experiment. Averaged over the entire experiment, the additional N₂O emissions caused by elevated CO₂ equaled 4738 kg CO₂-equivalents ha⁻¹, corresponding to more than half a ton (546 kg) of CO₂ ha⁻¹ which has to be sequestered annually to balance the CO₂-induced N₂O emissions. Without a concomitant increase in C sequestration under rising atmospheric CO₂ concentrations, temperate grasslands may be converted into greenhouse gas sources by a positive feedback on N₂O emissions. Our results underline the need to include continuous N₂O flux measurements in ecosystem-scale CO₂ enrichment experiments.     

关中灌区间作套种的带型研究

在陕西关中平原较高水肥条件下,间作套种的产量、产值和产能分别比单作复种增加10—15%、14%和10%。间作套种,带型是关键。宽带型中有的无间套优势,有的优势甚小。模糊综合评判表明,窄带型中,小麦玉米两茬套种,2.5尺带较佳,小麦玉米和大豆三茬问套,3.5尺带最优。本文还讨论了影响小麦产量的边际效应,实播面积和玉米对带型反应的敏感性,以及间作大豆的光竞争等问题。