三种沙棘浆果成熟过程中的糖、有机酸、黄酮醇和类胡萝卜素组分的变化

在Askola、Hergo和Leikora三个德国沙棘品种的浆果中,根据不同采集时间来测定其可溶性固形物,糖,有机酸,黄酮醇和类胡萝卜素的含量,用以提供一个更为完善的浆果成熟期内沙棘品质变化的情况。沙棘浆果成熟期内主要有机酸是苹果酸（1940-4660mg／100g）,奎宁酸（810～2820mg／100g）,维生素C（180～370mg／100g）和柠檬酸（90～160mg／100g）。在这3个沙棘品种中所有有机酸的浓度在成熟过程中呈现显著下降趋势。而其糖类如葡萄糖（0．26～2．10g／100g）和果糖（0．14～0．54g／100g）在3个品种中成分变化略有不同。所有3个沙棘品种维生素C浓度在成熟过程中呈现下降趋势。含有的主要黄酮醇是异鼠李素（350-660mg／kg）,槲皮素（30～100mg／kg）和山奈酚（2-5mg／kg）。在3个沙棘品种中黄酮醇浓度在成熟过程中显示出不同的变化趋势。主要类胡萝卜素是玉米黄素（30～150mg／kg）,β-胡萝卜素（3～50mg／kg）和β-隐黄质（5～19mg／kg）。基因型对类胡萝卜素的收集和类胡萝卜素的形态都有影响,但在3个沙棘品种成熟期间类胡萝卜素浓度呈现增加趋势。在成熟期间抗氧化剂的分类表现出不同的组成变化,最大浓度也出现在不同的收获期。     

二穗短柄草叶绿体RNA编辑位点的预测及其鉴定

RNA编辑是陆生植物叶绿体转录后基因表达调控的一种重要方式。为进一步探讨单子叶植物RNA编辑功能及其发生机制,本研究通过生物信息学方法,对二穗短柄草叶绿体的81个蛋白编码基因的RNA编辑位点进行了预测和鉴定分析,结果发现78个基因存在编辑位点,共检测到176个编辑位点,都是C到U的转换。其中ndhB最多,为14个编辑位点。为验证预测结果,利用blast工具比对了NCBI的二穗短柄草EST数据库,最终确定存在于17个基因中的34个编辑位点是真实存在的,其中19个为沉默编辑,15个为有效编辑。与5个不同单子叶禾本科物种18个蛋白编码基因的RNA编辑位点的比较发现,在rpoB-206位点,只有二穗短柄草发生了编辑,且只有ndhD-295(293)为部分编辑位点。     

Global Bibliometric Analysis of the Research in Biochar

Global interest in studying biochar stems from its ability to sequester carbon in soil and render nutrients and moisture more readily available to root systems. Therefore, a bibliometric analysis was conducted to investigate global scientific publications related to biochar research, providing insight into the number of articles published, journal platforms, subjects, citations, and overall trends. The primary databases employed were the Web of Science and Science Citation Index. A total of 1,697 articles published between 2000 and 2015 were evaluated. This systematic bibliometric analysis will assist research groups and individuals to understand global biochar research trends and focus future research. The influence of biochar on soil, plants, and the environment continues to require greater attention.     

黄土高原不同生态类型区果园地土壤肥力特征综合评价及其区域差异特征研究

以黄土高原典型苹果园地为研究区域,采用野外调查与试验分析相结合的方法,选取6个土壤养分指标:有机质、全氮、速效磷、全磷、速效钾和全钾,应用多元统计分析方法,分析了黄土高原典型苹果园地3个区段(陕西凤翔、陕西长武、陕西延安)0—300cm土壤剖面层土壤养分含量的分布特征及差异性。结果表明:不同苹果产区土壤养分含量差别明显,3个试点各类果园0—300cm土层土壤全氮含量平均值,全磷含量平均值、速效磷含量平均值、全钾含量平均值、速效钾含量平均值由大到小依次为凤翔长武延安;长武凤翔延安;长武凤翔延安;凤翔长武延安;长武凤翔延安。不同苹果产区果园0—300cm土层土壤氮磷钾全量和速效量剖面分布特征类似,除全钾和速效氮外其余养分全量和速效量剖面分布具有明显"表层积聚效应。长武和延安的0—300cm土层土壤有机质含量的剖面分布特征类似,没有明显的垂直分层现象而凤翔0—100cm土层速效钾含量随土层加深而迅速降低,100—200cm土层内有机质含量的剖面含量没有明显的变化。陕西长武地区土壤养分指数为0.24比陕西凤翔地区(0.23)的高;陕西凤翔地区养分指数(0.23)比陕西延安地区的(0.22)高。针对不同区域果园土壤养分含量差异,提出果园施肥建议:凤翔果园应该增施有机肥和氮肥,增施钾肥。长武果园增施有机肥,氮磷钾肥配合施用。延安地区土壤养分状况最差,应加大施肥力度,增施有机肥,氮磷钾肥配合施用,实行平衡施肥。     

野生斑鳠西江地理群的遗传多样性分析

为了解斑鳠(Mystus guttatus)不同地理种群之间的遗传分化程度,基于RAPD技术,分析了珠江水系西江段野生斑鳠的遗传多样性。利用20个随机引物对30个斑鳠个体的基因组DNA进行了PCR扩增,共扩增出3210条DNA片段,平均每个个体扩增出107条带。在检测到的107个位点中,多态位点数为48个,占44.9%,仅有一个引物S30没有扩增出多态带。个体间最大的遗传距离0.2804,最小的遗传距离0.0467,平均遗传距离0.1526±0.037,种群内个体间平均的相似率为84.7±3.7%。     

新疆干旱区土地盐渍化信息提取及实证分析

对提取干旱区盐渍化信息的若干方法进行了评述,并且选取位于干旱区地带的盐渍化典型区域——阿克苏地区的库车、新和、沙雅县以及和田地区的于田县作为研究区进行实证分析。并采用同一时相的ETM+数据,运用K-T变换、比值变换以及通过NDVI指数和分类来提取信息发现效果明显。通过实证分析发现:虽然研究区都地处塔里木盆地周边地区,一个是塔北绿洲,另一个是塔南绿洲。但由于水文(盐渍化形成的关键)、气候(形成盐渍化土壤的驱动力)、地形(盐渍化土壤分布及差异的主要因素)、人类活动(盐渍化土壤形成的重要因素)等因素差异的存在,导致了盐渍化情况的差异。     

基于遥感的疏勒县植被覆盖时空变化研究

【目的】评价疏勒县生态环境质量及生态环境演变过程。【方法】基于Landsat遥感影像数据,利用归一化植被指数NDVI、像元二分模型、中心迁移模型等方法分析了1996-2017年疏勒县植被覆盖时空演化。【结果】①疏勒县植被覆盖分布总体以高植被覆盖为主成大面积片状分布,中、低植被覆盖主要以盖孜河和克孜河为轴线,相对围绕高植被覆盖分散分布;②1996-2017年疏勒县植被覆盖面积和覆盖度均呈增加趋势。2017年的植被覆盖面积比1996年增加了456.4 km²,增加率为38.3%;③疏勒县植被覆盖空间变化上存在一定的区域性和时段性差异。区域上,南部乡镇覆盖度明显增加;时段上,2009-2013年植被覆盖面积增加最明显;④1996-2017年疏勒县植被覆盖中心整体往东南迁移;⑤气候变暖对疏勒县植被覆盖度变化有一定的影响,但短期内人类活动影响更大。灌区改造高效节水、耕地开垦、农作物的种植及林带面积的增加是植被覆盖面积增加的主要因素。【结论】综上可知,气候变暖和生态治理工程等人类活动因素可能是疏勒县植被覆盖面积与覆盖度呈增加的主要原因,这表明疏勒县生态环境保护与治理是科学合理的。     

Cotton Chemical Topping by Applying DPC in Different Cotton-Growing Regions

[Objective] The objective of this study was to investigate the stability and universality of cotton chemical topping by applying mepiquat chloride (1,1-dimethyl-piperidinium chloride, DPC) in different cotton-growing regions. [Method] Field experiments were conducted in 2018 at 10 locations in the Yellow River basin (Hejian and Handan, Hebei province; Dezhou and Wudi, Shandong province), the Yangtze River basin (Dafeng, Jiangsu province; Huanggang, Hubei province), and Xinjiang area (Shihezi location I and loacation II, northern Xinjiang and Luntai and Shaya, southern Xinjiang). Local cultivars/lines were used, and the experiments were performed using a randomized complete block design with three or four replicates. Accompanied with typical DPC multi-application in each location, chemical topping was conducted at 10 days before manual topping (T1) or at the same time with manual topping (T2) by applying four dosages of DPC (0, 90, 180, 270 g·hm^－2), manual topping was used as the first control and non-topping as the second control. [Result] The time of chemical topping significantly affected cotton plant height (except for the results in Handan, Dezhou and Wudi) and the number of fruit branches (except for the results in Dafeng and Huanggang). It was observed that earlier chemical topping would result in lower cotton plant height and a fewer fruit branches. In Hejian and Shihezi location I, the average plant height across DPC chemical topping at T1 stage was not only lower than that of T2 stage but also 3.3 cm and 4.6 cm lower than that of manual topping, respectively. In most locations, chemical topping at T1 stage increased around two fruit branches per plant compared with manual topping, while in T2 stage the increased fruit branches per plant ranged from 2.3 to 7.7. Also, we found that a higher dosage of DPC resulted in shorter plant height (except for that in Huanggang). In some locations, plant heights of chemical topping with 180 g·hm^－2 or 270 g·hm^－2 DPC were even shorter than that of manual topping. The number of fruit branches per plant of 0 g·hm^－2 DPC increased by 2.4-8.3 compared with manual topping. However, chemical topping with 90-270 g·hm^－2 DPC significantly reduced the number of fruit branches compared with 0 g·hm^－2 DPC. There were no significant differences in the number of fruit branches among three DPC dosages (90, 180, and 270 g·hm^－2). In Handan, seed cotton yield of chemical topping at T2 stage was significantly lower than that of manual topping due to the decreased boll number, which is possibly associated with the high temperature and drought weather after chemical topping. While at other locations, most treatments of chemical topping by using DPC did not produce significant effects on yield. In addition, chemical topping by using DPC did not delay cotton maturity, characterized by their similar boll-opening rate and the first harvest rate to those of manual topping before spraying harvest aids. [Conclusion] Cotton chemical topping with DPC is more stable and universal across different cotton-growing regions. We suggest that 90-180 g·hm^－2 DPC could be used at the same time with manual topping for cotton chemical topping.     

沙枣树胶对红葡萄树提取液抗氧活性保护作用的研究

该文就沙枣树胶对红葡萄树提取液抗氧性的保护作用及其变化进行了初步研究,结果表明红葡萄树提取液具有极强的抗羟自由基(H0·)能力,而抗超氧阴离子自由基(O-2·)的能力较弱,即在空气中易氧化、抗氧活性迅速降低、消失;当加入沙枣树胶初期,其抗氧性能迅速降低,3d后开始上升,15d后其对超氧阴离子自由基清除率达到30%,60d后对羟自由基清除率达到68%,其后,一直保持稳定.在沙枣树胶的多糖活性成分的作用下,红葡萄树胶的抗氧活性显著增强,稳定性提高.研究结果初步表明,沙枣树胶对红葡萄树提取液的抗氧活性具有显著的保护作用.     

不完全分形多孔介质热导率模型

将多孔介质的物理构成分为具有分形结构的团聚体集合和不具有分形特性的固相和孔隙相,建立了简化单元体模型解释其微观结构。结合多孔介质在干燥过程中热量守恒定律和傅里叶导热定律导出了材料总有效热导率模型。此模型无经验常数,每一个参数都有物理意义。研究结果表明,有效热导率与迂曲分形维数、面积分形维数、孔隙率和热风温度呈反比,与热风速率和时间呈正比。