香蕉束顶病毒PCR检测技术研究

建立了聚合酶链反应（ＰＣＲ）扩增技术检测香蕉组织和单头蚜虫内的香蕉束顶病毒（ＢＢＴＶ）,并报道了ＢＢＴＶ免疫捕捉ＰＣＲ（ＩＣ－ＰＣＲ）和直接结合ＰＣＲ（ＤＢ－ＰＣＲ）检测方法,ＩＣ－ＰＣＲ和ＤＢ－ＰＣＲ分别能从４μｇ和０．４ｍｇ香蕉叶组织中检测到ＢＢＴＶ。     

直接模拟蒙特卡罗方法在CFD冲蚀预测中的应用

为研究气固两相流中固体颗粒间碰撞对冲蚀的影响,提出一种利用直接模拟蒙特卡罗(Direct Simulation Monte Carlo,DSMC)方法和计算流体力学(CFD)计算颗粒间碰撞的冲蚀预测方法。使用Eulerian-Lagrangian方法,将气相作为连续相,通过Navier-Stokes方程求解,颗粒平移运动由离散相模型(DPM)求解。颗粒平移运动由Eulerian-Lagrangian框架下的DPM求解,计算颗粒间碰撞运动时采用DSMC方法以少量采样颗粒代替真实颗粒,碰撞的发生条件通过修正的Nanbu方法判定。分析气固两相流中颗粒间碰撞对弯管冲蚀速率和颗粒分布的影响,结果表明:使用DSMC方法计算颗粒间碰撞,Oka模型的平均百分误差从39.2%降低至27.4%;计算颗粒间碰撞时弯管内拱侧的无颗粒区变小,最大冲蚀位置沿外拱轴线后移5°,同时V形冲蚀痕迹的两翼向外侧扩大。使用DSMC方法计算颗粒间碰撞可以明显降低模型误差,考虑颗粒间碰撞的Oka模型与实验结果偏差最小,是冲蚀预测的最佳模型。     

Wide hybridization and introgression breeding in safflower: Effectiveness of different selection methods

Possibility of using interspecific hybridization to increase genetic diversity of drought tolerance in safflower (Carthamus tinctorius L.) and effectiveness of different selection methods is poorly understood. The main objectives of this study were to evaluate the effectiveness of (a) interspecific hybridization to expand genetic diversity in safflower for agronomic traits and drought tolerance in advance generations and (b) different selection methods (direct vs. indirect) for improving seed yield. Interspecific hybridizations were performed between species of C. tinctorius × C. palaestinus (TP), C. palaestinus × C. oxyacantha (PO) and C. tinctorius × C. oxyacantha (TO). Based on the field screening of genotypes in F3 generation, four groups of selected genotypes (derived from combination of direct and indirect selection under both drought and normal environments along with selection based on drought tolerance index (STI)) were evaluated in F4 and F5 generations. Indirect selection for seed yield was significantly more efficient than direct selection. Selection in stress environment resulted to more efficiency than selection in normal environment. No significant difference was observed between direct selection and selection based on STI. The result showed that TP was the best population to combine high seed yield and drought tolerance in safflower.     

Marker‐assisted breeding for improvement of anaerobic germination in japonica rice (Oryza sativa)

Direct seeding is increasingly being practiced in rice cultivation areas because it saves labour and reduces cost of production and management. In this study, four japonica‐type breeding lines were developed from a cross of a japonica cultivar and an AG‐tolerant donor, KHO, using marker‐assisted selection. Validation of the target genes AG1 and AG2 in the selected lines was examined by PCR analysis and the background recovery rate by the recurrent parent was confirmed by genotyping using a 6K SNP chip. Compared to the recurrent, the survival rates of the selected lines were improved in a range from 33% to 115% in three conditions; in particular, the survival rate was increased in more than twice that of the recurrent parent under the hypoxic condition. The main agronomic trait, yield and quality‐related traits were similar to those of the recurrent parent. The use of these lines will contribute to the expansion of the cultivation area due to the proven economic benefits of direct seeding in Korea.     

金樱子(Rosa laevigata Michx.)叶片直接再生不定芽体系的建立

以金樱子组培苗的划伤叶片为外植体,研究了不同植物生长调节剂配比组合、暗培养时间、添加物L-脯氨酸、叶片不同部位对不定芽直接再生的影响。结果表明:当TDZ浓度为1.5 mg·L^-1、NAA浓度为0.000 5 mg·L^-1时,不定芽直接发生率最高,为9.5%;不同暗培养时间对不定芽直接诱导具有一定影响,暗培养时间为10 d时不定芽的直接发生率最高,为10.5%;添加了不同浓度的L-脯氨酸后不定芽的诱导率不增反降,所以以不添加L-脯氨酸为宜;叶片不同部位的再生率比较中,仅带叶叶柄可直接诱导出不定芽。综上所述,叶片直接再生不定芽的诱导方法是,以金樱子带叶叶柄为外植体,在直接诱导培养基上1/2MS+TDA 1.5 mg·L^-1+NAA 0.000 5 mg·L^-1+CH 100 mg·L^-1+AgNO3 10 mg·L^-1+蔗糖30 g·L^-1+琼脂7.5 g·L^-1,暗培养10 d后,转至正常光周期下培养3周左右,不定芽诱导率最高,为10.5%。所得不定芽在增殖培养基MS+NAA 0.1 mg·L^-1+6-BA 1.0 mg·L^-1生长3周后,增殖系数可达到3.5左右;将丛生芽切割成单芽后转入不含任何激素的MS培养基壮苗3周,幼苗可长高至3~5 cm;再转入MS+NAA 0.1 mg·L^-1培养基中生根,1个月后生根率达95%。     

甜菜DAMD-PCR体系的建立及优化

为了建立甜菜DAMD扩增体系,以期利用DAMD引物应用于甜菜品种指纹图谱的构建及分子标记辅助育种。本实验利用单因素变量的方法对甜菜DAMD体系进行优化。同时选用12个甜菜品种,利用优化的体系对25条DAMD引物进行扩增。获得甜菜的最适DAMD体系:总体积为20μL,包含模板DNA 10~80 ng、0.75 U的DNA聚合酶、0.2μL的d NTPs(2.5 mmol/L each)以及2.0μL的引物(10μmol/L)。同时25条引物均扩增出了清晰条带,除了个别引物多态性较差外,其余引物多态性都非常的丰富,其中引物62H(-)就可以把实验中用到的12个甜菜品种全部区分开。由此可见,DAMD引物的扩增效率很高,并且扩增结果稳定,条带清晰,非常适合甜菜品种指纹图谱的构建及遗传多样性分析。     

高强钢焊接薄腹工形截面双向压弯构件的稳定性

应用ANSYS有限元,分析了Q460高强钢焊接薄腹工形截面双向压弯构件的稳定性能,提出了可供实际应用参考的设计公式。分析中考虑的主要参数有腹板高厚比,构件长细比,翼缘宽厚比及荷载偏心率。结果表明,对受压为主的构件,腹板局部屈曲对构件稳定承载力影响较大,而对受弯为主的构件,这一因素对构件稳定承载力影响较小。有限元分析结果与现行规范方法计算结果比较表明,目前规范方法尚不能较好地计算高强钢焊接薄腹工形截面双向压弯构件的稳定承载力,因而提出了修正直接强度法,该法精度较好且偏于安全。     

液压外骨骼机器人非线性模糊滑模控制方法

针对液压外骨骼机器人系统建模困难的问题,提出一种利用自适应模糊逼近方法来实现对滑模等效控制的逼近,不需要对机器人的未知参数进行预先估计,同时设计可调参数的自适应调节律,增强系统的鲁棒性,引入一种类势能函数设计具有非线性积分项的滑模面,当误差较大时,积分效应适当减弱,防止产生较大的超调量;当误差较小时,积分效应适当增强,减小稳态误差。利用李雅普诺夫方法论证了该闭环控制系统的稳定性,并使用模糊切换方法来消除滑模控制抖振。最后,对液压助力外骨骼机器人系统进行轨迹跟踪及外干扰实验,结果验证了该方法的有效性,控制输出能快速平稳地跟随参考位置信号,且具有一定抗干扰能力。     

生物质热解气燃烧装置设计与燃烧特性试验

针对目前生物质热解气中焦油去除困难、焦油能量难以利用等问题,结合现有燃气燃烧器相关技术,开展了生物质热解气直接燃烧技术研究与试验。燃烧器理论耗气量为2~5 m~3/h,通过理论计算确定了燃烧器参数,设计了卧式燃烧室并安装烟气催化裂解装置及烟气检测装置,搭建了热解气燃烧试验平台,并对热解气的燃烧特性进行了试验研究。以花生壳为原料,在碳化温度500℃、滞留时间30 min的条件下进行连续热解碳化,产生的高温热解气直接通入燃烧设备。结果表明,燃烧设备性能较好,热解气燃烧过程稳定,燃烧效率达到98.5%,在催化剂的作用下,燃烧效率提高到98.9%,满足设计要求。     

施氮量对油后直播棉花产量、品质及生物量的影响

为研究施氮量对油后直播棉花生物量累积特征及其与产量、品质的关系,于2016-2017年在湖南常德设置了施氮量分别为0、90、180、270、360 kg·hm^-2氮肥水平试验。结果表明,在施氮量为0~360 kg·hm^-2范围内,施氮量越大棉株营养器官生物量累积越多,而棉株生殖器官生物量则在施氮量为270 kg·hm^-2时累积最多;皮棉产量、成铃数和单铃重均在施氮量为270 kg·hm^-2时达到最大;0~270 kg·hm^-2范围内,衣分随施氮量增加而增加。在施氮量为270 kg·hm^-2条件下,纤维长度和断裂比强度最高;适宜施氮量有利于纤维长度、断裂比强度的提高和马克隆值的优化,对伸长率和整齐度基本无影响。综上所述,适宜施氮量可提高棉花的产量、品质,洞庭湖棉区适宜的施氮量为180~250 kg·hm^-2。本研究结果为环洞庭湖棉区的氮肥合理运筹提供了技术参考。