A rapid extensigraph protocol for measuring dough viscoelasticity and mixing requirement

The extensigraph is particularly useful in characterizing dough viscoelastic properties; however, testing throughput for standard method is low due to the prerequisite for farinograph water absorption, long dough resting and milling to prepare large amounts of flour. Therefore, a rapid extensigraph method was developed that reduced sample size (165 g wheat) for milling and more than tripled throughput. Wheat is milled in Quadrumat Junior mill with a modified sieving system. The resulting flour (100 g) was mixed with a pin mixer at constant water absorption to allow the evaluation of wheat genotypes at the absorption level they are expected to perform. Dough was subsequently stretched by an extensigraph after 15 min of floor time and 30 min resting. Strong correlations for extensigram R_max (r > 0.93), extensibility (r > 0.64) and area (r > 0.88) were found for the proposed method compared to the standard method. Mixing parameters (time and energy) obtained during dough preparation provided further information about dough strength and mixing requirement. By significantly reducing sample size requirement and increasing testing throughput, this rapid extensigraph method can be widely adopted in milling and baking industry and meets the need for a fast evaluation of dough strength in breeding trials.     

Cultivation Influences on Soil Organic Carbon Associated with Texture in Seasonally Frozen Zones

[Objective] This study aimed to examine indicative roles of texture representing soil organic carbon presence and variability subsequent to cultivation under cold temperate climates with seasonal freeze-thaw events.[Method] Three chronosequences were selected for paired comparisons.Soil samples were collected at six depths with a 10 cm increment.Analysis of variance with general linear model and regression was performed for statistical analysis.[Result] In seasonally frozen soils where fragmentation of macroaggregates was stimulated,soil organic carbon level was positively associated with clay ＋ silt proportion due to a wider textural range,better than sole clay content.Exponential function better fitted the experimental data to present progressively increased effectiveness of clay ＋ silt content in maintaining carbon.Clay content explained 12％-41％ and 14％-43％ of variation via linear and exponential functions,respectively.Accordingly,clay ＋ silt content explained 47％-65％ and 46％-70％.[Conclusion] Texture reflected soil organic carbon occurrence as consequences of reclamation.For seasonally frozen soils with wider textural ranges,it is robust to adapt clay ＋ silt content as dependent variable and exponential function.The generated algorithms provided an available pathway to estimate soil organic carbon losses following cultivation and to evaluate soil fertility.     

闽北地区枫香优树子代生长性状变异分析及选择

在福建省三明市郊国有林场对来自安徽省南部黄山地区的53个枫香家系进行子代测定试验,开展优良家系选择。结果表明,14年生时,试验林树高、胸径、地径、材积、圆满度的平均值分别为9.87 m、7.87 cm、11.18 cm、0.0267 m3、0.72,变幅分别为0.90~16.7 m、2.30~15.60 cm、3.20~22.50 cm、0.00072~0.15060 m3、0.21~0.97,树高、胸径、地径、材积、圆满度的家系遗传力分别为0.476、0.550、0.531、0.520和0.414,单株遗传力分别为0.188、0.211、0.207、0.221和0.107。通过综合比较,从参试的53个家系中选择出9个速生优良家系,树高、胸径和材积的平均值分别为10.70 m、8.98 cm和0.0415m3,平均遗传增益分别为2.50%、5.00%和19.37%,这些优良家系适宜福建省三明地区推广应用。     

Salinity tolerance of wild barley Hordeum vulgare ssp. spontaneum

Salinity tolerance of 47 wild barley genotypes and six barley cultivars was evaluated under control and salinity stress (300 mM NaCl) conditions. Shoot and root dry weight (DW), plant height, membrane stability index (MSI), relative water content, survival rate, leaf malondialdehyde (MDA) and proline contents, root and leaf Na, K, Ca and K/Na ratio, and chlorophyll a fluorescence were measured. Salinity stress caused significant increase in the MDA, proline content, Na and Ca concentrations of the roots and leaves, but resulted in a decrease in the other traits. H. spontaneum genotypes were considerably less affected by the salinity than the genotypes of H. vulgare. Plant survivability was negatively correlated with the Na concentration (r =−.66) but positively correlated with the leaf K/Na ratio (r = .67) and MSI (r = .68). Tolerance mechanisms such as ion exclusion (Na) were likely to be present in the wild barley causing K/Na homeostasis as well as the much lower root and shoot Na, resulting in the higher survival rate.     

河南省羊肠道病毒的分离与序列测定

应用Vero细胞从河南省某腹泻羊场的粪便样品中分离出2株病毒。电镜观察显示,分离的病毒粒子直径大小为25~30 nm。单层免疫过氧化物酶对分离病毒进行了免疫学鉴定,结果显示分离的2株病毒均与羊肠道病毒CEV-JL14的高免血清发生强阳性反应。对RT-PCR扩增出的病毒基因片段进行了序列测定与比对分析,发现分离的2株病毒与CEV-JL14毒株处于同一分支,均为G种肠道病毒。本研究首次从河南省分离获得了羊肠道病毒,为进一步研究该病打下基础。     

海南岛西部橡胶人工林冠层温度变化及其与微气象要素的关系

冠层温度是表征植物生理生态过程及能量平衡状况的重要参数之一。为探讨热带森林冠层温度在不同时间尺度下的变化规律并且初步分析环境因素与冠层温度的关系,本研究利用红外温度传感器测定了海南岛西部橡胶人工林2017年全年的冠层温度数据以及同步得到的冠层微气象资料,对干季和湿季下海南岛西部橡胶人工林冠层温度（T_c）与大气温度（T_a）特征进行了分析,同时结合微气象因子进行了讨论。结果表明：橡胶人工林冠层温度全年各月日变化都为单峰曲线,相比T_a,T_c具有明显的位相前移、变化加剧的特点。白天林冠边界层处于不稳定状态,林冠为土壤-植物-大气连续体（Soil-Plant-Atmosphere Continuum,SPAC）的热源;夜晚林冠边界层为逆温层结,呈稳定状态,林冠为SPAC的冷源。湿季冠层温度高于干季。若仅考虑T_a,T_c与T_a之间具有很好的线性关系,其线性方程为T_c= 1.033T_a-0.656;若同时考虑大气温度（T_a）、净辐射（R_n）、相对湿度（RH）与风速（V）等微气象因子,其复相关系数表明全年均呈极显著相关,偏相关系数表明干季冠层温度变化主要受T_a、R_n和RH的影响,其次受V的影响;湿季主要受T_a与RH的共同作用,R_n与V对其的影响相比可忽略不计。此研究结果初步揭示了橡胶人工林冠层温度的全年变化规律及其与众多微气象因子之间的关系,为进一步探究冠层温度变化及其影响机制提供科学依据。     

木棉雄蕊特征与其繁殖策略的关系分析

采用野外观察和实验室检测方法,对云南省个旧市冷墩村的木棉花部结构、雄蕊特征、花粉活性进行研究。结果表明,自然种群中花部形态特征具有一定变异性,3层雄蕊变异系数大小关系显著。在湿度为60%、温度为35℃时花粉活性最强。研究发现,木棉雄蕊长短变化可能有利于不同传粉生物传粉效率提高和增强适应性;木棉高层雄蕊花药个体大、花粉数量多、活性高,适应干热河谷传粉繁殖条件;温度较低时,底层花药花粉活力相对较高,可为逆境环境下木棉高层花药受损后提供后备花粉源。文章就木棉花部形态与繁殖关系、木棉形态及花粉活力对繁殖的影响进行讨论。     

2018年中国部分地区猪瘟病毒2.1d亚型新流行株的基因组特征分析

为了解中国猪瘟病毒（classical swine fever virus，CSFV）的分子流行病学及遗传变异情况，本研究应用RT-PCR方法对2018年采集自河南、河北、山东、黑龙江和辽宁5个省份的350份疑似CSFV感染的病料进行E2和NS5B基因扩增，并对PCR产物进行测序和序列分析。结果显示，350份样品中21份为CSFV阳性，共获得14株CSFV的E2基因序列和7株CSFV的部分NS5B基因序列。E2全基因、NS5B部分基因序列分析表明，21份阳性样品均属于近年来在中国流行的CSFV 2.1d亚型，且新发现的2.1d亚型CSFV与中国较早2.1d亚型CSFV毒株间同源性差异不大，新发现的2.1d亚型CSFV分离株在E2基因的6个氨基酸（R³¹、S³⁴、W¹⁸²、K²⁰⁵、K³⁰³、A³³¹）上具有相同的分子特征，E2蛋白中15个位点上的半胱氨酸均未发生变异。韩国2.1d亚型CSFV在E2蛋白上具有3个独特的氨基酸（N⁹⁷、K¹⁵⁹、R²⁰⁵）特征，并且发现了韩国毒株YC11WB可能作为2.1b和2.1d亚型CSFV过渡毒株的证据，流行于中国和韩国的2.1d亚型CSFV可能分别来自于本国早期2.1b亚型CSFV的衍化。本研究证实，2018年中国及周边国家CSFV较为活跃，且流行毒株依然以2.1d亚型为主，为中国科学防控CSFV提供了依据。     

多花黄精不同种源种实形态性状遗传变异研究

旨在阐明多花黄精种实形态性状在种源水平上的遗传变异规律,为多花黄精优良种源选择提供理论依据。以栽植在同质栽培园的18个多花黄精种源为材料,比较了不同种源多花黄精浆果、种子的纵径、横径、侧径等形态性状,以及单果重和种子千粒重等性状的差异。多花黄精种实形态性状及其单果鲜重和种子千粒重在不同种源间均存在着极显著差异;多花黄精浆果形态性状两两之间存在极显著正相关关系,种子形态性状两两之间也存在显著或极显著正相关关系,但绝大多数浆果形态性状与种子形态性状之间的相关性不显著;多花黄精种实形态性状在种源水平上不存在明显的地理变异模式;多花黄精种子形态性状在种源水平上的广义遗传力达到强度遗传范围,能比较稳定地遗传。可以考虑利用种子千粒重这一指标作为多花黄精优良种源选择的间接指标。     

EMS诱导水稻‘一目惚’表型变异和部分基因表达变异的比较

本研究利用甲基磺酸乙酯(Ethy methan sulfonate)试剂胁迫诱导粳稻品种‘一目惚’(Hitomebore),获得性状稳定遗传的水稻矮杆突变体(E58),对株高、分蘖、千粒重等表现与相同环境生长下的野生型‘一目惚’对照(E63)进行对比分析,结果表明,该突变体田间表现为植株矮化,分蘖增多,千粒重减少,且株高与对照相比呈极显著差异,分蘖呈显著差异,千粒重呈极显著差异。EMS诱导的序列变异可能对基因表达产生影响,进而引起水稻矮化的表型变异。根据前人试验结果,应用Real-time PCR对与胁迫及矮化相关的39对引物中筛选出24对引物进行Real-Time PCR扩增,结果表明:引物OsNR1、OsP5CS、OsGS1;1、OsGDH1、OsHKT1;5、OsNRT1;1、OsGDH3、OsAKT1、OsAMT2;3、OsGS1;2、OsSOS1、OsNHX2、OsNRT2;1、OHAK16、OsGS2、OsHAK1、OsGDH2、OsAMT3;3在E63、E58表达差异极显著;OsHAK10、OsNHX1、OsAMT1;1表达差异显著;OsNADHGOGAT、OsFd-GOGAT、OsGS1;3表达差异不显著。EMS诱导对部分水稻基因表达产生影响,从而影响水稻表现型,为进一步工作提供科学依据。