Seedling biomass allocation and vital rates of cloud forest tree species: Responses to light in shade house conditions

Patterns of above- and below-ground biomass allocation in seedlings of nine common cloud forest (CF) tree species of western Mexico were examined under varying controlled light conditions using artificial shade houses. We analysed the relationships between vital rates (growth and survival) and four morphological traits (SLA, biomass allocation to stems, leaves and roots). We hypothesised that these traits represent differentiation axes in the way seedlings face the heterogeneous light regime typical of the CF understorey. For all species, traits between the different light levels, i.e. allocation to leaves, roots and stems differed among light levels. Five species had the largest SLA in the lowest light levels at the end of the experiment (Citharexylum, Dendropanax, Fraxinus, Quercus and Magnolia). Juglans was the only species with a large SLA at the highest light level (377.47 cm² g⁻¹). In contrast, light levels did not cause any significant variation in SLA of Persea and Simplococarpon at the end of the experiment. The relative height growth rates (RHGR) of the seedlings of five species were significantly different between light levels (P < 0.05). Overall, all species grew better in the highest light levels. The RHGR of three species were correlated positively with SLA. In turn, allocation to stem, leaves and root biomass were strongly correlated with the RHGR of five species (e.g. Citharexylum, Dendropanax and Fraxinus). Survival did not vary significantly between treatments in any species, only in the case of Simplococarpon (P < 0.05) and was correlated with all morphological variables. For this species, Peto and Peto's test showed a significantly larger survival of seedlings in the highest light level. The mean responses of these species based on all traits to the controlled light variation did not differed significantly. Our results show that these species display a wide range of resource allocation patterns when exposed to the varying light conditions that may be found in the forest understorey and highlight the role of morphological traits in this variation.     

浊点萃取-分光光度法测定水样中痕量铅

将浊点萃取与分光光度计联用,研究了以双硫腙-丙酮作为络合剂,用TritonX-100非离子表面活性剂萃取痕量铅离子的各种影响条件。结果表明：在最佳条件下测定铅的检测限为3.43μg/L,工作曲线回归方程为A=0.010 1C＋0.008,相关系数r2=0.990 3,线性范围为20～100μg/L。将该方法用于环境水样中痕量铅的测定,获得满意的结果。     

新疆林果大数据管理平台的应用实例分析——以沙棘为例

基于新疆林果大数据管理平台,按照统一标准整合新疆沙棘资源数据,建立融合气象、土壤、有害生物等数据的沙棘资源数据库,对新疆沙棘资源进行动态监测和分析。得出新疆沙棘资源总面积为10 640 hm2,阿勒泰地区为最大优势区,种植面积达到7 033 hm2,占全疆沙棘总面积的66.10%,种植株行距主要以1.5 m×4.0 m为主,新疆沙棘成熟期集中于9、10月份,所受病害以溃疡病为主。     

机载探测仪在辽宁人工增雨中的应用

依据实时探测的温度、露点温度、液态水含量等要素及计算“冰水转化”区,从而判断增雨作业区域,确定催化时机、部位和催化剂种类。结果表明,当“冰水转化”区大于零且液态水含量大于等于0．5g／m3时,条件①温度小于等于-8℃且大于等于-24℃时,开始播撒碘化银烟条;条件②温度小于0℃且大于-8℃时,开始播撒液体二氧化碳试剂。机上探测设备的应用,较好地提高了增雨作业的科学性,解决了机上催化剂选择、播撒区域、时机确定等问题。同时,利用雷达探测资料,对催化区和非催化区、催化前和催化后的雷达最大反射率进行了对比,分析得出催化区雷达最大反射率强度明显增强,因而从物理检验的角度证明了人工增雨机上催化剂播撒决策系统指挥有效。     

人工鱼群优化在云计算环境中任务调度算法

针对云计算的编程模型框架,提出基于郭涛思想的人工鱼群算法,通过该算法不但能找到总任务完成时间较短的调度结果,而且该调度结果的任务平均完成时间也较短。通过仿真实验将该算法与基本的人工鱼群优化算法进行比较,结果表明,该算法优于基本的人工鱼群优化算法,是一种云计算环境下有效的任务调度算法。     

基于博士点立项建设的高校图书馆服务保障研究

以河北联合大学图书馆为例,阐述了图书馆应以本校博士点授权单位立项建设为契机,通过加强资源和服务两个体系的建设,为博士点授权单位立项建设提供强有力的支撑。     

农业科研院所云财务服务管理研究

基于农业科研院所目前财务管理现状及问题,提出了横向覆盖、纵向渗透的云财务服务管理理念及其实施需求,以消除在核算管理模式选择中的弊端。     

网络环境下图书馆与馆员发展的趋势分析

 

评述了利用因特网获取信息的优势与局限性，对网络环境下未来图书馆的发展趋势进

行了分析，并据此对未来图书馆员的新职能进行了预测。

     

云计算在高通量测序数据分析中的应用

高通量测序技术在DNA测序发展历程中具有里程碑的意义。本文首先介绍了高通量测序及其主要应用。高通量测序应用广泛,产生的数据具有数据量大、序列短等特点。高通量数据分析面临巨大挑战。一方面,我们可以不断改进算法,来提高软件运行的效率,另一方面,我们可以利用更多更快的硬件资源提高数据处理的效率。云计算具有低成本、高自动性、高灵活性等特点,可作为高通量数据分析的一种解决方案。云计算已经在高通量数据分析中有广泛的应用。本文介绍了几款常用软件和综合分析平台,为选择和使用和该类软件提供指导。     

外来入侵杂草对广州市白云山的危害及其防治策略的探讨

本文分析了广州市白云山风景区分布的有害外来杂草的种类及对风景区产生的危害，并对如何防治的策略进行了初步的探讨。