模拟铅胁迫下玉米不同基因型生长与铅积累及各器官间分配规律

我国遭受重金属污染的土地中有87%左右是中轻度污染土壤类型,深入研究不同植物对重金属的吸收和转运积累规律,是科学利用植物和土壤资源的重要基础工作.通过玻璃网室盆栽模拟污染的手段,研究了玉米6种基因型在铅中度污染胁迫(800mg·kg-1)与轻度污染胁迫(400mg·kg-1)下的植株生长、铅吸收积累及其在玉米不同器官间分配的规律.结果表明,不同铅污染胁迫下,玉米不同基因型的生长及铅吸收量达到极显著差异(P＜0.01),铅在不同器官之间的分布形式也存在显著的基因型差异.轻度铅污染胁迫不同程度地促进玉米所有供试基因型的生长,而中度污染胁迫下糯玉米基因型生物量最大.与正常土壤对照条件下的表现相比,不同程度铅污染胁迫下基因型申甜1号的生物量增幅最大,表现出较强的铅耐受能力.不同基因型的玉米体内铅积累量随着污染水平的提高而增加,各器官内铅积累浓度差异规律为根>叶>茎>穗.掖单13号具有较强的铅转运能力(TF=0.662 8),申甜1号的生物富集能力最强(BCF=0.0264),掖单13号和申甜1号均具有较强的铅吸收和积累能力,属于潜在的高积累基因型.但掖单13号根部富集量少而穗部积累多,申甜1号根中铅积累较多而果穗中较少.2个甜玉米基因型果穗内铅积累量较少,其含量符合国家规定的食品生产相应的安全标准.     

基于FLANN数据融合的木材含水率检测方法

针对木材含水率的检测精度受到多种环境因子(温度、平衡含水率、风速等)的影响,提出了一种基于函数联接型神经网络FLANN的数据融合方法以消除环境温度对木材含水率检测精度的扰动。FLANN能利用函数扩展替代多层感知器(MLP)的隐含层,将输入信号空间维度下的线性不可分类的问题,扩展至较高信号空间维度的超平面上,简化了MLP的架构。与MLP相比,FLANN具有结构简单、收敛速度快和计算量小的特点。仿真结果及实验验证表明:基于FLANN的数据融合方法,能有效消除环境因子的扰动,并可实现木材含水率的稳定、实时、高精度检测。     

功能竹的定向培育及其可行性(英文)

功能竹是指经过人工优选、培育和生产出来的具有某种特殊作用或功能的栽培竹品种。功能竹的定向培育,就是根据市场前景广阔和价值最大化原则,运用有效的科学和技术手段并按照人类需求进行的功能竹培育。对于定向培育的功能竹,通常要求其性状相对一致、稳定,品质优异且便于推广,有利于组织科学化、标准化、产业化和规模化生产,目的是在同等时间和空间条件下,选择、培育和发展具有一个或多个指向明确的功能或特点的特色栽培竹品种,在不造成环境压力的情况下,尽可能满足消费者的物质和精神需求,并为生产者赢得更多的经济利益。作者通过认真分析论证,认为该思路不仅具有技术的可行性、资源的可行性和政策的可行性,而且具有经济的可行性和市场的可行性,这对立足中国自身资源特点发展绿色经济具有重要意义。     

山东栒子全长转录组测序数据组装及功能注释

山东栒子是中国山东省的特有种,现已处于极度濒危状态。目前,山东栒子的分子生物学研究较少,基因数据库资源极度缺乏,急需探究其生物学遗传信息,以加快对山东栒子的保护遗传学工作。本研究以山东栒子叶片、花、成熟果实为实验材料,利用PacBio Sequel测序平台对其转录组进行全长转录组测序。共得到高质量去冗余的转录本53932个,作为最终转录本序列。预测到的CDS区共52490个;对其SSR位点进行分析,对测序得到Unigenes进行单核苷酸至六核苷酸重复的SSR位点搜索,共搜索到26796个SSR位点。对非冗余转录本利用BLAST软件与NR、Swissprot、GO、COG、KOG、KEGG 6个数据库进行比对,一共成功注释了53319个Unigenes,其中与NR数据库进行比对中注释为苹果的的相关基因数量最多,其次是白梨和桃;在GO数据库中有33305条山东栒子Unigenes被注释分类,由生物学过程、细胞成分和分子功能三部分组成;在与COG数据库比对中,共有23910条比对到了同源序列,且一共被分为25类;在与KEGG数据库的一系列比对中,可将Unigenes映射到126条代谢通路中。本研究在高通量全长转录组水平对山东栒子进行了系统研究,这为进一步开展山东栒子的分子标记开发和挖掘优良基因提供了科学依据,从而推动山东栒子的保护与利用。     

Strong functional stability of soil microbial communities under semiarid Mediterranean conditions and subjected to long-term shifts in baseline precipitation

We investigated the effect of soil microclimate on the structure and functioning of soil microbial communities in a Mediterranean Holm-oak forest subjected to 10 years of partial rain exclusion manipulations, simulating average drought conditions expected in Mediterranean areas for the following decades. We applied a high throughput DNA pyrosequencing technique coupled to parallel measurements of microbial respiration (R_H) and temperature sensitivity of microbial respiration (Q₁₀). Some consistent changes in the structure of bacterial communities suggest a slow process of community shifts parallel to the trend towards oligotrophy in response to long-term droughts. However, the structure of bacterial communities was mainly determined by short-term environmental fluctuations associated with sampling date (winter, spring and summer) rather than long-term (10 years) shifts in baseline precipitation. Moreover, long-term drought did not exert any chronic effect on the functioning of soil microbial communities (R_H and Q₁₀), emphasizing the functional stability of these communities to this long-term but mild shifts in water availability. We hypothesize that the particular conditions of the Mediterranean climate with strong seasonal shifts in both temperature and soil water availability but also characterized by very extreme environmental conditions during summer, was acting as a strong force in community assembling, selecting phenotypes adapted to the semiarid conditions characterizing Mediterranean ecosystems. Relations of climate with the phylogenetic structure and overall diversity of the communities as well as the distribution of the individual responses of different lineages (genera) to climate confirmed our hypotheses, evidencing communities dominated by thermotolerant and drought-tolerant phenotypes.     

Effect of germination time and temperature on the functionality and protein solubility of sorghum flour

Sorghum was germinated for different time (12, 24, 36 and 48 h) at different temperatures (25, 30 and 35 °C) and the changes in their nutritional and functional properties of germinated sorghum flour were assessed and compared with native sorghum flour. Germination inversely affects the crude protein, fat, fibre and ash content. A decrease in water absorption and swelling power and increase in oil absorption capacity was observed due to enzymatic starch modification as the germination duration progressed. Germination of sorghum increased the gel consistency while paste clarity was decreased as compared to native flour. Proteins were modified by action of enzymes during higher germination time and temperature conditions, which results in significantly higher protein solubility of germinated sorghum flour, which also result in enhancing the foaming and emulsifying properties of the flour. Lowest % synersis value and least gelation concentrations were observed in native sorghum has, which increased during germination and were highest in sorghum germinated for 48 h at 35 °C. Germination in overall can be used as low cost natural bio-processing technique for the preparation of modified flour with enhanced function properties without chemical modification or genetic engineering.     

施肥对割草地羊草功能性状和化学计量学的影响

本研究以羊草（Leymus chinensis）为研究对象,测定羊草植物功能性状、营养元素和化学计量等多个指标,进行多角度综合系统的研究,阐释羊草割草地羊草种群对不同改良措施的响应特点及变化规律。运用单、双因素方差分析、相关分析和主成分分析方法对相关指标进行统计分析。结果表明：大多数羊草功能性状对施肥处理较为敏感,但随着施肥年份增加,部分指标敏感程度减弱;高浓度（N 10.5 g·m^-2+P 5.1 g·m^-2）施肥处理显著增加了株高和茎长,茎长成为羊草株高增长的主要因素;高浓度（N 10.5 g·m^-2+P 5.1 g·m^-2）施肥处理有利于羊草种群地上生物量的增加;羊草氮含量随着施肥年份增加逐渐增加,羊草氮含量与羊草C：N存在高度负相关,施肥（N 10.5 g·m^-2+P 5.1 g·m^-2）处理下羊草叶片和茎的C：N,羊草个体和叶片C：P最低。     

高产棉花太阳辐射能利用率及干物质分配规律研究

通过对1988～1989年高产棉花栽培试验结果进行分析发现,棉花的太阳辐射利用率在叶面积系数小于2.0时随叶面积系数的增加而线性增加,大于2.0时增加变缓。从生育时间看,7月中旬前太阳辐射利用率指数上升,7月中旬至8月底相对稳定在1.2～1.4克/兆焦左右,9月以后又不同程度线性下降。生长季内子棉太阳辐射经济效率1988和1989年分别为0.14和0.15克/兆焦。收获指数与最大叶面积系数呈显著负相关;盛花期之前棉株各器官之间的同伸关系或明显,盛花期后器官的生长相互间无明显的确定性关系。如能调节密度与叶面积系数的关系,使得既提高5～6月的辐射能利用率,同时使7～8月叶面积系数维持在3.0～3.5的适宜范围内,9～10月群体又不早衰,则有利于获得高产。