The use of T‐DNA tagging to isolate mutants of Colletotrichum gloeosporioides and Colletotrichum acutatum with reduced virulence against Hevea brasiliensis

Agrobacterium tumefaciens‐mediated transformation (ATMT) is being increasingly recognized as an effective insertional mutagenesis tool in studies of filamentous fungi for gene discovery and functional analysis. We developed and optimized ATMT for 2 Colletotrichum species, Colletotrichum gloeosporioides and Colletotrichum acutatum, the causative agents of Colletotrichum leaf disease in rubber trees in Southern China. A. tumefaciens strain AGL‐1 carrying an ILV1 gene and a green fluorescent protein gene were used to transform the conidia of these 2 Colletotrichum species. The transformation efficiency was correlated with the co‐cultivation duration and bacterial cell concentrations, which reached 300–400 transformants per 1 × 10⁶ conidia after optimization. Southern blot analysis indicated that about 60.0% of the C. gloeosporioides transformants and 46.2% of the C. acutatum transformants had a single copy of T‐DNA in their genomes. Fungal genomic DNA segments flanking the T‐DNA were identified in the transformants through thermal asymmetrical interlaced polymerase chain reaction followed by sequencing. The flanking sequences from 4 C. acutatum and 7 C. gloeosporioides transformants showed moderate or weak homology to the NCBI database entries. Some sequences matching those reported virulence‐related genes. The results suggest that the T‐DNA inserted mutants banks constructed are useful for the discovery of new or important genes and to elucidate their function in the 2 Colletotrichum species.     

干湿循环强度与频度对花岗岩红壤孔隙分布的影响

为探明干湿循环频度与强度对花岗岩红壤孔隙分布的影响,该研究通过测定不同干湿循环条件下土壤水分特征曲线计算孔隙分布,并采用孔隙分形维数量化干湿循环效应对土壤孔隙结构变异的影响。结果表明：干湿循环对＜0.2 μm、＞3～15 μm和＞57 μm三类当量孔隙产生了显著影响。孔隙结构的再分布主要集中于前4次干湿交替之中,其后干湿交替的影响效应随着频度的增加逐渐减小并趋于稳定。随着强度增强,非活性孔隙（＜0.2 μm）和中孔隙（0.2～30 μm）逐渐发育成大孔隙（＞30 μm）。同时,干湿循环强度对大孔隙（＞30 μm）影响显著（P＜0.05）,贡献率达65.2%,而干湿循环频度对非活性孔隙（＜0.2 μm）影响显著（P＜0.05）,贡献率达91.9%。此外,土样孔隙分形维数D经干湿循环后逐渐减小,且与强度呈负相关（R2=0.868）,表明孔隙结构向大孔隙均质化方向发展。研究结果说明季节性降雨干旱引发的干湿循环效应主要影响大孔隙的生成,增强了土体的均质性和导水能力,加剧了岩土体失稳崩塌的风险。     

GIS在福建龙眼低温冻害分析中的应用

 为减少福建龙眼在低温冻害中的损失,实现科学合理的种植布局,进行本研究。根据龙眼的生长情况、受害程度与年度极端最低气温、种植区域的坡向、坡度的关系,确定龙眼冻害等级指标。利用福建68个气象台站的地理信息资料,建立龙眼冻害指标的空间分布特征模型,通过GIS技术推算出50m×50m分辨率的冻害指标空间分布。利用GIS的空间分析能力,得出福建龙眼低温冻害的分布规律。     

龙门式点样仪精度的研究

为了实现龙门式点样仪的高精度运动控制,采用一种消除反向误差方法,消除双输出轴电机驱动设备两侧松紧程度不同的同步带轮运动过程中,设备返回启动位置时,连接两侧运动机构的桥梁与启动时产生的夹角,提高了设备的重复定位精度;改进了一种标定方法,提高了设备的定位精度。通过基于ARM9的微控制器对是否采用上述方法进行对比实验,利用激光跟踪仪测量了设备的重复定位精度以及定位精度。实验结果表明:未采用上述方法,设备重复定位精度为0.09 mm,定位精度为0.07 mm。采用上述方法,设备的重复定位精度可达0.01 mm,定位精度可达0.03 mm。     

海口地区的木材平衡含水率

海口地区的木材平衡含水率蔡则谟（中国林业科学研究院热带林业研究所广州５１０５２０）关键词木材平衡含水率，海口研究各气候区的木材平衡含水率（Ｗｅ）对木材干燥有重要意义，自５０年代以来，华东、华北、东北、西南、西北及中南等地区的有关单位在这方面做了许多工...     

杂交水稻骨干亲本鉴定标记的开发及应用

随着现代杂交稻育种的发展,利用表型进行品种特异性鉴定、品种真实性鉴定以及种子纯度测试的方法表现出诸多局限性,已经不再适合现代育种的进程.本研究利用水稻基因组插入缺失(insertion-deletion,InDel)位点开发了9个InDel标记用于鉴定生产中常用的29份杂交稻骨干亲本.利用标记电泳图谱做了供试材料的聚类...     

均匀设计优化香草兰中香兰素的超临界萃取工艺

研究超临界Co2萃取香草兰豆荚中香兰素等香料成分的工艺,以香兰索产量为检测指标,使用均匀设计-偏最小二乘法回归分析,优化萃取工艺的压力、温度、时间和夹带剂乙醇的体积4个因子,确定最佳提取工艺条件为:压力41.10 MPa,温度50℃,时间180 min,夹带剂体积5.0 mL,此时,20g香草兰原料萃取香兰素的理论产量为177.211 mg.对该技术应用于香草兰中香兰素提取产业化的前景和可行性进行分析探讨.     

Polyaniline-Modified Quartz Crystal Microbalance Sensor for Detection of Formic Acid Gas

A polyaniline-modified quartz crystal microbalance (QCM) sensor was obtained through immobilizing the polyaniline film on the silver electrode surface of quartz crystal resonator by an electrochemical method. The sensor was studied for detecting the formic acid gas of different concentrations, and the results showed that the resonant frequency of QCM decreased quickly in the beginning and tended to be constant in the end when exposed to formic acid gas. The frequency shifts decreased faster as the concentration of formic acid gas increased. And the frequency shifts of the QCM sensors were found to be linearly related to the concentration of formic acid gas, which might be used to estimate the concentration level of the formic acid gas within the range of experimental concentrations. The result of on-line monitoring test fully indicated that the QCM sensor responded effectively to the increasing concentration of formic acid and had important practical significance and broad application prospect in real-time detection of antique conservation environment in the museum.     

山东聊城引种3种观赏竹的适应性

研究了引种观赏竹对低温的生理响应,综合评价其抗寒能力,以期为竹资源在北方的推广提供科学指导。以山东省聊城市百竹园的金镶玉竹(Phyllostachys aureosulcata 'Spectabilis’)、黄纹竹(Ph. vivax 'Huanwenzhu’)、紫竹(Ph. nigra)3种引种观赏竹为研究对象,研究了3种引种观赏竹的出笋率及电导率、超氧化物歧化酶(SOD)活性、可溶性糖、可溶性蛋白、游离脯氨酸、丙二醛(MDA)含量等6个抗寒生理指标,采用熵权TOPSIS法进行抗寒性综合评价。结果表明：出笋率从高到低依次为金镶玉竹、黄纹竹、紫竹。人工低温处理下,随低温胁迫的加剧,3种竹叶的电导率均呈上升趋势,金镶玉竹的电导率最高;MDA含量表现为先降低后上升;金镶玉竹叶片中渗透物质含量高于黄纹竹和紫竹,可溶性糖、可溶性蛋白质、游离脯氨酸的含量升高;金镶玉竹叶片SOD酶活性显著高于其他2个竹种;基于熵权法进行抗寒性综合评价,可溶性蛋白质含量在抗寒指标中占的权重最大(23.69%),其次为游离脯氨酸(22.56%)和可溶性糖(15.40%);TOPSIS评价得出金镶玉竹抗寒能力最强,其次为黄纹竹、紫竹。     

育苗播种双向气动控制系统的设计研究

在参照原有的单向穴盘育苗播种机的基础上提出了双向育苗气动作业的思路,设计了一套双向播种的气动控制系统,并完成吸投互替的双向播种过程.设计的适用双向作业的双向育苗播种机结构,是利用传感器采集和D/A转换信号,由单片机控制电磁阀动作来完成双向播种的自动控制过程.同时,对整体系统进行了仿真分析.结果表明,其系统大大提高了生产效率,并为工业化育苗播种提供了一种新的思路.