盐胁迫下宁夏枸杞Na+吸收及Na+/H+转运蛋白与H+-ATPase基因表达的研究

为从分子水平揭示宁夏枸杞钠的吸收积累机理,本试验采用原子吸收分光光度法和实时荧光定量PCR(RT-qPCR)方法,对盐胁迫下宁夏枸杞根中Na⁺、K⁺含量以及质膜和液泡膜Na⁺/H⁺转运蛋白与H⁺-ATPase基因表达水平进行测定分析。结果表明,相同胁迫时间下,随着NaCl处理浓度的增加,枸杞根系中Na⁺浓度总体呈缓慢增加趋势,K⁺含量呈先增加后减少趋势,Na⁺/K⁺比值呈先减少后增加趋势;编码质膜和液泡膜的Na⁺/H⁺转运蛋白基因LbSOS1、LbNHX1以及液泡膜H⁺-ATPase基因LbVHA-C1表达量均呈升高趋势,质膜H⁺-ATPase基因LbHA1表达量呈先升高后降低趋势。相同NaCl处理浓度下,随着胁迫时间的延长,Na⁺含量总体呈增加趋势,K⁺含量呈先增加后减少趋势,Na⁺/K⁺比值呈增加趋势。LbSOS1、LbNHX1表达量总体呈先升高后降低趋势,LbVHA-C1、LbHA1表达量总体呈降低的趋势。相关性分析显示,不同胁迫时间下,枸杞根中LbSOS1、LbNHX1、LbVHA-C1和LbHA1表达量与Na⁺含量存在一定的正相关或负相关。上述结果表明,在低浓度NaCl胁迫时,维持枸杞体内较高的K⁺/Na⁺比值是宁夏枸杞耐盐的主要方式之一,同时也说明在胁迫初期,质膜和液泡膜的Na⁺/H⁺转运蛋白与H⁺-ATPase参与了枸杞细胞中Na⁺及时排出胞外和区隔于液泡,从而保持了根细胞内Na⁺的稳定性。此外,随着胁迫时间的延长和NaCl处理浓度的增加,LbSOS1、LbNHX1、LbVHA-C1和LbHA1的表达水平均降低,而 Na⁺积累量大幅增加,致使枸杞抗盐性降低。本研究揭示了宁夏枸杞的耐盐机理,为利用宁夏枸杞改良宁夏大面积盐碱地提供了理论依据。     

有机质浸染砂水泥土的力学特性及本构关系

为研究海南省海湾地区分布的有机质浸染砂水泥土的力学特性,该文首先对有机质浸染砂水泥土和标准砂水泥土进行无侧限抗压强度对比试验(采用配合比均为熟石灰掺入比7.5%、水泥掺入比20%、水灰比0.45),定量分析养护龄期对其无侧限抗压强度及试样破坏形式的影响。然后对有机质浸染砂水泥土进行单轴抗压试验,获得了水泥土材料的应力-应变全过程曲线、刚度变化规律以及改进邓肯-张本构模型。结果表明:1)有机质浸染砂水泥土试样的破坏类型为塑性剪切破坏和脆性剪切破坏;2)有机质浸染砂水泥土抗压强度随着养护龄期的增加基本呈指数形式增长,但在养护龄期14 d后,增长速度逐渐降低并趋于稳定;3)随着养护龄期增长,水泥土刚度增加。在加载初期,水泥土切线模量随着轴向应变增加而增大,呈现刚度硬化现象;4)基于单轴抗压试验得到应力-应变全过程曲线,可分为2个阶段:塑性阶段、软化阶段;5)通过对应力-应变全曲线的描述,得到了修正的邓肯-张模型,确定模型参数后,与实测数据对比发现,该修正模型可以模拟有机质浸染砂水泥土的应力-应变关系。     

运用植被指数时序特征对落叶松人工林分类

为探究植被指数时序特征是否有利于落叶松人工林提取,以孟家岗林场为研究试验区域,根据落叶松人工林季相和物候特征,利用Landsat8OLI影像数据提取研究区内5种植被的归一化植被指数(I NDV)、差值植被指数(I DV)、比值植被指数(I RV)、增强型植被指数(I EV),构建相应的植被指数时序特征。采用最大似然和随机森林两种方法对单一时相影像和加入植被指数时序特征的影像进行对比试验。结果表明:影像中加入植被指数时序特征后,最大似然算法的分类总体精度为89.53%,Kappa系数为0.87,比单一时序特征的影像分类精度提高了13.35%;随机森林算法的森林类型分类总体精度为93.22%,Kappa系数为0.92,比单一时序特征的影像分类精度提高了19.8%。因此,加入植被指数时序特征后能得到更高的落叶松人工林提取精度。     

Grain Quality as Affected by Down-regulation of Expression of Different ALK Alleles in indica Rice (Oryza sativa L.)

【Objective】Gelatinization temperature (GT) is one of the key physicochemical properties in rice quality, which is mainly regulated by ALK (SSII-3) gene. In general, there are two ALK alleles among indica cultivars. To detect their functional differentiation in indica rice,【Method】Zhenshan 97B (a high GT variety carrying ALKc allele) and Longtefu B (a low GT variety carrying ALKb allele), were used as receptors for the generation of transgenic rice with down-regulation of ALK expression by RNA interference (RNAi).【Result】Down-regulation of ALK gene significantly decreased the GT of the transgenic lines. Due to the difference of original GT between the two receptors, the GT of transgenic rice lines derived from Zhenshan 97B (a high GT variety) decreased significantly, but it is slightly decreased in transgenic plants derived from Longtefu B (a low GT variety). The differential scanning calorimetry (DSC) results showed that the initial temperature of RNAi transgenic rice was significantly lower than the corresponding control and the transgenic lines were gelatinized in advance. The peak value of GT(Tp) in RNAi rice grains was significantly lower than that of the control under Zhenshan 97B background. However, Tp of RNAi rice grains under Longtefu B background was significantly lower than the control to a lesser extent. Also, down-regulation of ALK expression had a significant effect on rice physical-chemical characteristics. An increase of apparent amylose content in RNAi transgenic plants was detected due to the decreased expression of ALK gene. Besides, the pasting properties showed that down-regulation of ALK gene had obvious effects on peak viscosity and breakdown value, improving the taste of the transgenic rice. The gel consistency was significantly different among Zhenshan 97B RNAi lines and their parents, but no difference was found in Longtefu-derived transgenic lines.【Conclusion】RNA interference to ALK allele expression had a significant effect on rice quality, especially the gelatinization characters. Down-regulated expression level of ALKc allele would cause larger variation of physical-chemical characteristics between transgenic rice and their parent than that of ALKb allele.     

石粉与减水剂兼容性试验研究

为发挥石粉生态混凝土绿色环保的特点,在满足规范和成本要求的条件下,提高石粉的利用价值,以确定适用减水剂类别。通过在石粉砂浆中应用4种常用的减水剂,研究了其不同减水剂环境下石粉砂浆和凝结时间及抗压强度之间的关系。结果表明:石粉砂浆在不同减水剂环境中凝结时间及抗压强度没有明显区别,进一步为高掺量石粉生态混凝土的应用与发展提供参考。     

基于状态变换法的车辆悬架系统时滞反馈控制

为了提高车辆行驶平顺性和稳定性,研究悬架系统中时滞补偿控制效果,本文以赛欧轿车悬架系统为基础,建立2自由度车辆半主动悬架系统模型,设计了时滞反馈控制器,采用理论与试验相结合的方法对系统时滞反馈控制特性进行研究。首先建立含时滞的悬架系统动力学方程,采用常微分理论和多项式判别方法分析系统稳定性,并通过时域与频域仿真对结果进行验证。研究表明:采用传统二次型最优控制律对含时滞的悬架系统进行控制,当系统控制时滞较大时,系统定性特性可能会发生改变,甚至会失稳发散。为保证系统的稳定性,采用状态变换方法设计时滞反馈最优控制律,仿真表明采用该控制律不仅可以保证系统稳定性,系统的减振特性亦有改善。最后搭建了悬架时滞反馈控制平台,基于时域辨识方法测得系统固有时滞为0.065 s,通过对相同工况下仿真结果与试验结果进行对比,发现两者具有较好的一致性,误差在15%以内,满足业内使用要求,表明研究可信,结果可为主动/半主动车辆悬架控制器实际设计应用提供参考。     

生长环境及收获期对野鸦椿属植物三萜类化合物含量的影响

【目的】研究不同生境和收获时间对圆齿野鸦椿不同部位总三萜类化合物积累的影响情况,为其药用价值和科学栽培的研究奠定基础。【方法】选择3个低海拔地区的8年生圆齿野鸦椿,分别于2014年11月和2015年3月采集其叶片、枝条和果实,选择高海拔地区6年生的野鸦椿和圆齿野鸦椿,于2014年8月分别采其叶片和枝条,对其总三萜类化合物含量进行了测定和比较分析。【结果】1)8月采集的叶片中三萜类化合物的含量,野鸦椿高于圆齿野鸦椿,且其含量差异呈显著性水平;但是,8月采集的枝条中三萜类化合物含量,野鸦椿低于圆齿野鸦椿。2)圆齿野鸦椿不同部位的总三萜类化合物含量存在差异,且2个月份采集的含量高低顺序均为叶片>枝条>果皮>种子,均以叶片中的含量为最高,依次为9.06%(农大)、7.14%(清流)和6.85%(邵武)。3)11月采集的圆齿野鸦椿样品中的三萜类化合物含量高于3月所采样品中的含量,其叶片中的总三萜类化合物含量最多可提高172.91%。4)圆齿野鸦椿叶片、果皮和种子中的三萜类化合物含量与试验地的海拔高度、年降水量均表现出极显著的负相关关系,与年均气温存在极显著的正相关关系,其叶片中的三萜类化合物含量还与年均无霜期呈正相关关系,其枝条中的三萜类化合物含量与各地理和气象因素之间的相关性均不显著。【结论】圆齿野鸦椿的叶片采收期长于野鸦椿;低海拔、较少降水量和年均气温较高有利于圆齿野鸦椿植株对三萜类化合物的累积,这3个因子可以作为圆齿野鸦椿适宜栽培区域的划分指标;夏季采摘野鸦椿叶片,秋冬季采摘圆齿野鸦椿叶片,所采叶片的总三萜类化合物的含量均较高。     

Serum amyloid A (SAA) mRNA expression in chicken and quails in response to bacterial stress

Monitoring of acute phase proteins such as serum amyloid A at gene expression level may provide quick information about immune status of the host and its susceptibility towards common infections. Present study was carried out to evaluate and compare the mRNA expression of SAA gene in Rhode Island Red chicken (RIR) and Japanese quails using real time PCR analysis in response to inactivated Salmonella gallinarum culture. The results showed that expression of SAA gene was approximately 17–33 folds higher in case of birds administered with bacterial culture when compared to un-inoculated controls and expression was higher and quicker in case of quails than RIR chicken. The SAA genes from chicken and quail were cloned and upon sequence analysis it was observed that deduced amino acid sequence of SAA from chicken and quails were having approximately seven percent variation which might have significance in function of this protein in these species.     

Effect of delaying the time of insemination with sex-sorted semen on pregnancy rate in Holstein heifers

The objective of the study was to evaluate the interval from onset of oestrus to time of artificial insemination (AI) to obtain the optimum pregnancy rate with sex-sorted semen in Holstein heifers. Heifers in oestrus were detected and inseminated only by using heat–rumination neck collar comprised electronic identification tag at the age of 13–14 months. Heifers (n = 283) were randomly assigned to one of three groups according to the timing of insemination at 12–16 hr (G1, n = 97), at 16.1–20 hr (G2, n = 94) and at 20.1–24 hr (G3, n = 92) after reaching the activity threshold. The mean duration of oestrus was 18.6 ± 0.1 hr, and mean peak activity was found at 7.5 ± 0.1 hr after activity threshold. The mean interval from activity threshold to ovulation was 29.4 ± 0.4 hr. The overall pregnancy per AI (P/AI) was 53.0% at 29–35 days and 50.9% at 60–66 days after AI. There was a significant reduction between G1 (13.8 ± 1.4 hr) and G3 (7.9 ± 1.4 hr) related to the intervals from AI to ovulation time. Sex-sorted semen resulted in significantly higher P/AI at 29–35 days when heifers inseminated in G3 (60.9%) after oestrus than those inseminated in G1 (49.5%) and G2 (48.9%). In terms of fertility, when the temperature–humidity index (THI) was below the threshold value (THI ≤65) at the time of AI, there was a tendency (≤65; 57.2% vs. > 65; 47.1%) for high pregnancy rate. There was no effect of sire on P/AI. In addition, the interaction of the technician with the time of AI was found significant, and three-way interaction of technician, sire and time of AI was tended to be significant on pregnancy rate. Thus, in addition to delaying the time of insemination (between 20.1 and 24 hr) after oestrous detection, THI and experienced technician were also found to be critical factors in increasing fertility with the use of sex-sorted semen in Holstein heifers.     

生物炭折流湿地对生活污水的净化效果

为提升西北地区农村生活污水的治理水平,结合西北地区气温特征,以生物炭为主体构建了折流湿地,并分析其对生活污水中污染物的净化效果。结果表明:在水温8～12℃条件下,折流湿地的最佳水力停留时间(HRT)为2.5 d,此时,湿地中污水的化学需氧量(COD)、氨氮(NH_4~+-N)、磷酸盐(PO_4~(3-)-P)、悬浮物(SS)的去除率分别为90.51%、72.38%、90.73%、94.57%。此外,各自污染物去除率与其停留时间和沿程均呈显著正相关(P0.05)。折流湿地经过12个月的运行,对COD、NH_4~+-N、PO_4~(3-)-P、SS的年平均去除率分别为88.16%、83.16%、92.55%、96.30%,且出水水质稳定。生物炭作为折流湿地填料对COD、PO_4~(3-)-P、SS的去除过程均较好地符合一级动力学模型(R~20.91),并且对SS具有较快的去除速率。研究表明,生物炭作为折流湿地填料具有良好的应用价值,对解决西北地区农村水污染问题具有重要的意义。