Comparative Study on Floral Organs and Pollen Characteristics of Different Varieties of Sorrel

The floral organ morphology,pollen morphology,quantity,and viability of Rumex,Rumex hanus F1,Rumex hanus 1,and Rumex hanus 2 were compared and analyzed.The results showed that the longitudinal diameter of petals was not significantly different among different varieties of sorrel,and the transverse diameter and corolla diameter showed differences to varying degrees.They all had six stamens and three stigmas.The pollen shape of the four varieties was prolate,and the polar view was trilobated and round.They all had three germinal furrows,and the outer wall of the pollen was decorated with small cavities and spiny patterns,with warty protrusions.The equatorial axis length of pollen of different varieties of sorrel was significantly different(P<0.05).There were no significant differences in pollen amount among different varieties.There were six anthers in a single flower,featuring anther dehiscence.The pollen viability of Rumex hanus 1 was significantly lower than that of the other three varieties(P<0.05).Therefore,through the analysis of the floral organs and morphological characteristics of anthers of sorrel,the varieties of sorrel can be effectively distinguished and identified.

同时测量温度和应变的全单模光纤马赫-曾德尔干涉仪

为了实现低成本的温度和应变同时测量,利用光纤熔接机的熔融放电原理制备了基于全单模光纤(SMF)的花生和J型结构级联的马赫-曾德尔干涉仪(CPJS-MZI)。首先利用光纤熔接机的球形程序将两段单模光纤的端面熔成球形,再将小球熔接到一起形成花生型结构;然后在距离花生结构15mm处,将两根单模光纤端面错位一定距离,对其进行熔接形成J型结构;最后对所制备的器件进行温度和应变传感性能的测试。实验发现,CPJS-MZI单个干涉峰强度和波长对应的温度灵敏度分别为-0.012 5dB/℃和52.9pm/℃,应变灵敏度分别为0.015 2dB/με和-11.44pm/με。结果表明,基于SMF的CPJS-MZI可利用单峰实现温度和应变的同时测量,且具有尺寸小、制备容易、成本低等优点,在同时测量温度和应变传感领域具有潜在应用价值。

可双参量同时测量的光纤磁场传感器

设计并制作了一种马赫-曾德尔干涉仪(Mach-Zehnder Interferometer,MZI)与光纤布喇格光栅级联的光纤磁场传感器,其中MZI由相当于分光器的锥结构和相当于耦合器的花生锥结构级联组成,封装在填充了磁流体的毛细管中.由于磁流体的有效折射率会随着外界磁场强度的改变而变化,故可通过观察干涉谱的特征波长的变化来测量外界磁场强度,而光纤布喇格光栅透射峰对磁场强度不敏感.当磁场强度由0mT变化到20mT时,马赫-曾德尔干涉峰的灵敏度为0.11nm/mT.温度特性实验测得马赫-曾德尔干涉峰和光纤布喇格光栅透射峰的温度灵敏度分别为0.401 5nm/℃和0.011 4nm/℃.因此,可利用敏感矩阵实现双参量同时测量.

Characteristics of soil microbial community functional and structure diversity with coverage of Solidago Canadensis L

The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.

The Roles of Plant Secondary Metabolites from Cowpea Floral Structures in Resistance to the Flower Bud Thrips

Floral structures of six cowpea （Vigna unguiculata） cultivars were analysed for secondary plant metabolites （polyphenols, terpenoids and flavonoids） to study their relationships with resistance to Megalurothrips sjostedti （Trybom）. Polyphenols varied significantly （P 〈 0.001） among the floral structures of the cultivars at the same growth stage. Significant negative correlations were obtained between polyphenols and damage indices （r = -0.57）, mean adult counts （r = -0.56） and mean larval counts （r = -0.64） of resistant cowpea cultivars especially in the late season, indicating that polyphenols play a significant role in cowpea resistance to M. sjostedti. High levels of polyphenols obtained from Sanzibanili and Sewe cultivars, coupled with highly significant correlations between the polyphenols and thrips population on resistant cultivars, and their damage indices, suggests that these polyphenols could be inhibitors or deterrents in this case. Terpenoid extracts （10 mg/mL） of IT90K-277-2, Sewe, Sanzibanili, TVu 1509 and KV - 404-8-1 racemes; KV ~ 404-8-I and TVu 1509 floral buds; IT90K-277-2, Sewe and Sanzibanili flowers caused significant （P 〈 0.001） larval mortalities, since mortality ranged between 56.7%-96.7%. Hence terpenoid extracts from floral structures of the cultivars are biologically active and confers antibiotic resistance to M. sjostedti larvae; this compound could be promising candidates for genetic transformation of cowpea cultivars.

基于七芯光纤的高灵敏度液位传感器

提出并研制了一种基于单模-花生-七芯-花生-单模光纤结构的液位传感器。该传感器采用光纤“花生结构”作为耦合器以提高单模光纤和七芯光纤的耦合效率,第一个光纤“花生结构”用以激发光纤包层模,第二个光纤“花生结构”将包层模与纤芯基模进行耦合而产生干涉。由于包层模与纤芯基模在七芯光纤中传输时存在相位差,所以当环境溶液的液位发生改变时,相位差也随之改变,从而导致透射光谱发生改变。本文对七芯光纤长度分别为24、28、32 mm的传感器进行了液位和温度响应特性的实验研究。实验结果表明,随着液位升高,传感器的透射光谱发生蓝移,三个传感器的水溶液液位灵敏度分别为-0.4069、-0.2739、-0.1653 nm/mm,其液位测量范围分别为24、28、32 mm。在35~90℃的水温变化范围内,传感器的透射光谱随着温度的上升发生红移,三个传感器的温度灵敏度分别为0.0885、0.0740、0.0879 nm/℃。实验表明该传感器具有灵敏度高、成本低、制作简单等特点,在石油化工等领域具有较好的应用前景。

Optical fiber magnetic field sensors with peanut-shape structure cascaded with LPFG

An optical fiber magnetic field sensor for the dual-parameter simultaneous measurement is proposed and demonstrated. The sensor head is constructed by a peanut-shape structure and long period fiber grating(LPFG) coated by magnetic fluid(MF). The external magnetic field intensity can be measured by the variation of characteristic wavelength(Dip1 and Dip2) in interference spectrum since the effective refractive index of MF changes with external magnetic field intensity. When the external magnetic field intensity changes from 0 mT to 20 mT, the magnetic field sensitivities of Dip1 and Dip2 are -0.064 nm/mT and -0.041 nm/mT, respectively. Experimental results show that the temperature sensitivities of the Dip1 and Dip2 are 0.233 nm/℃ and 0.186 nm/°C, respectively. Therefore, the simultaneous measurement of the magnetic field intensity and temperature is demonstrated based on the sensitive matrix. It has some potential applications in aerospace, environmental monitoring and medical sensing fields.

Magnetic field sensor based on peanut-shape structure and multimode fiber

An all fiber magnetic field sensor with peanut-shape structure based on multimode fiber(MMF) is proposed and experimentally demonstrated. The sensing structure and magnetic fluid(MF) are both encapsulated in capillary, and the effective refractive index of MF is affected by surrounding magnetic field strength. The measurement of magnetic field is realized by observing the wavelength drift of interference peak. The transmission spectrum generated by Mach-Zehnder interferometer(MZI) includes core-core mode interference and core-cladding mode interference. Experimental results demonstrate that the core-cladding mode interference is sensitive to magnetic field, and the magnetic field sensitivity is 0.047 8 nm/mT. In addition, two kinds of interference dips are sensitive to temperature, and the sensitivities are 0.060 0 nm/°C and 0.052 6 nm/°C, respectively. So the simultaneous measurement of magnetic field strength and temperature can be achieved based on sensitivity matrix.