Complexity of indica-japonica varietal differentiation in Bangladesh rice landraces revealed by microsatellite markers

To understand the genetic diversity and indica-japonica differentiation in Bangladesh rice varieties, a total of 151 accessions of rice varieties mostly Bangladesh traditional varieties including Aus, Boro, broadcast Aman, transplant Aman and Rayada varietal groups were genotyped using 47 rice nuclear SSRs. As a result, three distinct groups were detected by cluster analysis, corresponding to indica, Aus and japonica rice. Among deepwater rice varieties analyzed some having particular morphological features that mainly corresponded to the japonica varietal group. Some small seeded and aromatic varieties from Bangladesh also corresponded to the japonica varietal group. This research for the first time establishes that the japonica varietal group is a prominent component of traditional varieties in Bangladesh, particularly in deepwater areas.     

一维Theta-神经元网络中细胞耦合作用时间对细胞放电行为的影响

通过对一维Theta-神经元网络中细胞耦合作用时间的讨论,得到较长时间的耦合作用时间会使网络中单放电行波变为多放电行波,并通过数值模拟对理论加以验证.     

Effect of high rates of zinc on several crops grown on an irrigated plainfield sand

Abstract

A field experiment was conducted to determine whether Zn applied for pathogen control could accumulate to a level which would be toxic to snapbeans, cucumbers, or corn. Zinc sulfate (ZnSO₄) was applied at rates varying from 0 to 363 kg Zn/ha on a Flainfield loamy sand to approximate 3, 9, 27 and 81 years of fungicidal treatment.

Even at the high rate of Zn, yields of snapbeans, cucumbers, or corn generally were not reduced. As rates of applied Zn increased, there was a corresponding increase in the level of Zn in the leaf tissue of all crops grown. At the high Zn rate, snapbean and cucumber leaf tissue accumulated over 350 ppm Zn. Available soil Zn was extracted with 0.1N HCl, EDTA, or DTPA. Highly significant correlations were observed between the Zn removed by each extractant and plant tissue Zn, thus, indicating that the various extractants were equally effective in predicting Zn uptake.

Very little downward movement of Zn was observed. Two and one‐half years after application, the Zn had leached to a depth of only 30 cm in the soil profile at the higher Zn rates.

These data indicate that application of Zn‐containing fungicides and bactericides should not cause a Zn toxicity problem on the Plainfield sand in the foreseeable future.     

Comparison of physiological and yield traits between purple- and white-pericarp rice using SLs

Five physiological and eleven yield traits of two pairs of sister lines generated from a high generation with similar genetic background (SLs) for purple pericarp were investigated to explore the reasons behind low-yield production of colored rice. Of the five physiological traits examined, except grain anthocyanin content, there were generally similar trends between the P (purple-pericarp) lines and the corresponding W (white-pericarp) lines over two seasons (in the year 2009 and 2010 separately). The results demonstrated that the chlorophyll content of flag leaves, the net photosynthetic rate of flag leaves, and the grain anthocyanin content could be easily influenced by the environment. The physiological functions of the traits for the P lines were more active than those of the corresponding W lines in the year 2010. The grain anthocyanin content of the P lines was much greater in the year 2010 than in the year 2009 during the growth period. The investigation of yield traits revealed that the P lines had reduced 1000-grain weight, yield per plot and grain/brown rice thickness compared to the W lines. A difference comparison of these traits and a source-sink and transportation relationship analysis for these SLs suggested that small sink size was a key reason behind yield reduction of purple pericarp rice.     

不同氮磷配比对旱作土壤养分和油葵产量的影响

采用调查分析、田间试验等方法,研究了旱作土壤条件下油用向日葵氮磷肥的吸肥特性和对氮磷肥的吸收规律。结果表明:不同厚度(0～20cm)和(20～40cm)的土壤对养分的吸收呈现动态的变化特点,施氮270.0kg/hm2时吸收氮素分别为47.5和35.7mg/kg,相差24.8%;油葵产量为2 604.0kg/hm2,施磷100.05kg/hm2时吸收磷素分别为28.4和21.5mg/kg,相差24.2%,油葵产量为3 199.5kg/hm2。     

新型双足攀爬机器人夹持器模块的改型设计

文章详细设计和分析了一种应用于新型双足攀爬机器人Climbot的夹持器及其改型设计成果。由于原有夹持器存在诸多缺陷,例如结构复杂、可靠性低、加工工序复杂、制造成本高昂等。同时夹持器所属攀爬机器人的远景目标则是大规模推广应用,因此,设计制造一种结构简单、稳定可靠且成本低廉的夹持器成为当下的一个重要任务。针对这个现实需求,我们对原有夹持器进行了多次试验和深入分析,找出其中的不足,并对存在的问题提出多种解决方案。我们设计出一款新式夹持器,该夹持器结构简单,加工方便,而且部分关键零部件实现了标准化,成本得到了进一步降低。同时,在减轻夹持器重量的同时,通过结构的优化和材料选择,保证了夹持器应有的结构强度和刚度,满足设计要求。     

铁路货车电能收集装置的机械结构设计

针对转K6型转向架,设计了一种适用于铁路货车的低成本、利用自身能量发电,满足铁路货车低功率用电需求的供电装置。此装置利用滚珠丝杠将悬挂系统的上下振动转变为发电机转子的旋转。通过分析弹簧中的空间以及货车运行过程中的振动情况,设计了滚珠丝杠、外壳等零件,并通过SolidWorks软件对装置进行了仿真。     

Cost-efficient light control for production of two campanula species

A cost-efficient light control system based on weather forecasts, electricity prices and daily photosynthesis integral (DPI) was evaluated for application in the commercial production of the long-day (LD) plant Campanula portenschlagiana ‘Blue Get Mee’ and C. cochlearifolia ‘Blue Wonder’. Experiments were conducted under both autumn and spring conditions and included four treatments. Three treatments were controlled by the software system DynaLight Desktop which automatically defined the most cost-efficient use of supplemental light, -based on a predefined set point of DPI, forecasted solar irradiance and the market price on electricity. The set points of DPI in the three treatments were 300, 450 and 600 mmol CO₂ m⁻² leaf d⁻¹ and the treatments were compared with a traditional LD 19-h treatment. The DPI-based light control strategy resulted in very irregular light patterns including daily periods of solar irradiance combined with supplemental light in low light periods and a night period interrupted by irregular light breaks (NB-lighting). Both campanula species flowered in the DPI-based treatments during spring, but the flowering percentage was low and non-uniform during autumn. This was caused by a combination of the irregular light, low natural light intensities and a decrease in daily light integral (DLI), and could be restored by maintaining a continuous 19 h photoperiod with incandescent lamps (<5 μmol m⁻² s⁻¹), illustrating that photoperiod was an important factor for flowering in LD species grown under low light intensities. Growth in terms of carbon gain was marginally affected by the irregular light and a 25% reduction in electricity costs was achieved without major reductions in plant quality in spring. Our results illustrate that plant production of LD species can be maintained in a cost-efficient light control system where the use of supplemental light is based on weather forecasts and electricity prices.     

通河县林地保护规划落界数据说明

林地图斑落界是林地保护利用规划编制工作的主要环节,是落实林地图斑空间位置、核实资源基数,查清森林资源现状的基础性工作。笔者详细论述了通河县林地保护规划落界数据的基本情况、图斑落界方法和结果比较,对林地保护利用规划编制工作具有参考价值。     

高校图书馆为企业信息服务的探讨

分析了企业技术创新进行信息咨询的重要性和必要性,及高校图书馆为企业开发信息服务的优势,确立以虚拟企业为平台研究资源优化新模式,提供具有企业技术开发能力的决策性情报,企业新产品的开发中的信息分析与研究等企业技术创新的信息服务的构想。