聚果榕两种非传粉小蜂产卵与果实脱落的关系

下载PDF阅读器在聚果榕与其传粉榕小蜂Ceratosolen fusciceps组成的互利共生系统中,与传粉榕小蜂共存的还有榕树的寄生性小蜂Platyneura testacea和Platyneura mayri.这些寄生性小蜂由于不能给榕树带来任何收益而只是利用榕树的种子或与传粉小蜂竞争植物的雌花资源,因而可能导致榕树与榕小蜂之间合作系统的崩溃.植物果实的脱落机制普遍被认为是维持系统稳定的关键因素之一.然而,定量实验和野外观测发现P. mayri产卵并不会引起果实脱落,只有P. testacea产卵会使果实大量脱落.通过对3株样树进行比较发现:当产卵时的P. testacea数量越多时,它产生的瘿花数就越多,榕果发生脱落的比例越高.P. testacea的过度产卵是导致榕果选择性脱落的主要原因.结果表明:脱落机制并不能完全阻止非传粉小蜂的寄生,榕树只能选择性地脱落掉先于传粉小蜂产卵的榕果.这也同时表明维持榕树与榕小蜂互利共存的机制不仅仅只有榕果的脱落机制,可能还存在其它未被发现的机制.

复合垂直流人工湿地污水处理系统硝化与反硝化作用

研究了复合垂直流人工湿地各基质层的硝化与反硝化菌数量以及硝化与反硝化作用强度 .结果表明 ,基质中硝化菌数量为 7 5× 10 3 ～ 1 1× 10 5MPN·g-1,反硝化菌数量为 7 5× 10 6～ 1 1× 10 7MPN·g-1.硝化作用强度为 0 0 1～ 6 35 μg·(g·d) -1,反硝化作用强度为 3 37～ 4 19μg·(g·d) -1.沿水流方向硝化菌数量和硝化作用强度明显降低 ,其变化趋势呈显著正相关 (r =0 96 6 1,p <0 0 0 1) .反硝化菌数量和反硝化

武汉莲花湖微囊藻毒素含量变化特征及其影响因素的研究

采用现场采样及室内测试方法,研究了武汉莲花湖水华消亡过程中微囊藻毒素和环境生态因子的变化规律,并探讨了环境生态因子对微囊藻毒素产生的影响。结果表明,莲花湖微囊藻毒素含量以MC-LR为主,在水华消亡时大量释放到水体中,且较高的藻毒素含量能持续数天。对环境因子的相关分析表明,水体中的微囊藻毒素含量与铵氮、总磷显著正相关,与氮磷比显著负相关(P<0.05)。根据多元逐步回归统计进一步分析,筛选出相对重要的影响因子及合并共线形因子。经显著性检验,逐步回归统计结果为MC=13.62+5.77×NH4+-0.48×T

鱼类饲养对地下水中溶解态磷酸酶的影响

比较了鱼类养殖前后 ,地下水中正磷酸盐 (o P)浓度、碱性磷酸酶活性 (APA)在不同大小颗粒之间的分布、溶解态APA对pH、温度、CuSO4、ZnSO4、EDTA 2Na与表面活性剂 (CTAB与TritonX 10 0 )的应答方式及其动力学特征。养鱼之后 ,玻璃缸水中碱性磷酸酶表现出明显较高的活性 ,且以溶解态为主要存在形式 ,这种效应与鱼类的品种有关 ,溶解态APA的最大反应速度 (Vmax)与米氏常数 (Km)均明显提高 ,最适温度与pH值以及对于Zn2 + 的应答方式亦发生明显改变 ,颗粒结

团头鲂卵壳蛋白的分离与纯化

报道了一种从团头鲂卵壳中提取卵壳蛋白的有效方法。该提取液经SDS PAGE电泳鉴定后 ,证明有三条主要的蛋白带 ,其分子量分别为 6 4KDa,5 6KDa和 5 2KDa ,借助于制备型SDS PAGE电泳和电洗脱分离纯化技术 ,获得了三种高纯度的卵壳蛋白。

东湖间隙水自由碱性磷酸酶活性的季节性与组成的非均一性

国家自然科学基金 ( 2 0 1770 33、396 70 14 9、39170 16 5 ); 中国科学院东湖湖泊生态系统实验站基金项目

湿地中碱性磷酸酶的动力学特征与水生植物的关系

本文讨论了种植菹草 (PotamogetoncrispusL .)、水花生 (AlternanthearphiloxeroidesGriseb .)、紫背浮萍 (Spirodelapolyrhiza(L .)Schleid .)以及对照实验池 (12 .5m× 9.5m)过滤 (小于0 4 5 μm)与未过滤水样和沉积物中碱性磷酸酶的动力学特征及其分布 .水生植被能降低水样和表层沉积物酶的催化效率 ,抑制作用因植物的种类而异 ,且在未过滤水中表现得尤为突出 .因此 ,受抑制者多与较大的颗粒相联系 ,这一结

东湖紫外光敏感磷与可酶解磷的分布及其相互关系

初步讨论了武汉东湖不同工作站中紫外光敏感磷 (UVSP)与可酶解磷 (PHP)的季节变化以及间隙水中二者和碱性磷酸酶活性 (APA)的存在及其相互关系 间隙水中PHP与UVSP的存在 ,说明湖泊沉积物亦为间接有效的磷库 紫外光照射可显著提高间隙水中o P的浓度 ,却明显抑制溶解态碱性磷酸酶 (APase)的活性 ,这一结果未能支持UVSP释放o P的过程仍遵从酶促机制的假说 .

Transgene for growth hormone in common carp (Cyprinus carpio L.) promotes thymus development

The transgenic carp were produced by micro-injection of CAgcGHc into the fertilized eggs. Observation of the thymus development between the transgenics and non-transgenic controls was carried out. The thymus of one-year-old transgenics F1 showed a great increase in both size and weight. The unilateral thymus of the transgenics weighed from 190 to 295 mg with average 218.6 mg, whereas the unilateral thymus of the controls weighed 20-81 mg with average 42.5 mg; i.e. the thymus weight in the transgenics was 5.14 fold over that in the controls. The index of thymus/body weight in the transgenics was 2.97 fold over the controls. Light microscopy observation indicated that the thymus of the transgenics; well developed with the thickened outer region and compactly arranged thymocytes, while the thymus in the controls were degenerating with the thinned outer region, scattered thymocytes and groups of fatty cells. Further analysis with the electron microscopy revealed that pro-liferous cells in the transgenics; were mainly small lymphocytes and no pathological changes were found. The results confirmed that the "All-fish" GH-transgene promotes thymus development and thymocyte proliferation, and retards thymus degeneration. The study has laid a foundation for further analysis of the immunobiological function in GH-transgenic carp.

Dynamics of spontaneous emission from SiN with two-dimensional photonic crystals

We investigated the dynamics of spontaneous emission from a photonic crystal etched into a SiN slab. After fitting the decay curves of the emission to double exponential functions, we divided the dynamic process of the spontaneous emission into a fast process and a slow process. It was observed that the presence of the photonic crystal increased the proportion of the fast decay component, and consequently, the emission rate and time-integrated emission intensity were also enhanced. These enhancements were a result of the coupling of the guide modes to the leaky modes of the photonic crystal slab waveguide. (C) 2008 Optical Society of America.

Passive Q-switched mode locking of double-clading Yb : fiber laser with ion-implanted GaAs

We report the technique of the ion-implanted semi-insulating GaAs wafer used for passive Q-switched mode locking in double-cladding Yb:fiber laser. The wafer was implanted with 400-keV energy, 10(16)/cm(2) dose As+ ions, and was annealed at 600degreesC for 20 min. At the pump power of 5W, we achieved output power of 200mW. The repetition rate of envelope of Q-switched mode locking is 50-kHz with a FWHM envelope of 4mus. The repetition rate of mode locked pulse train was found to be 15-MHz. This is the first report of such a kind of laser to the best of our knowledge.

Thermal redistribution of localized excitons and its effect on the luminescence band in InGaN ternary alloys

Temperature-dependent photoluminescence measurements have been carried out in zinc-blende InGaN epilayers grown on GaAs substrates by metalorganic vapor-phase epitaxy. An anomalous temperature dependence of the peak position of the luminescence band was observed. Considering thermal activation and the transfer of excitons localized at different potential minima, we employed a model to explain the observed behavior. A good agreement between the theory and the experiment is achieved. At high temperatures, the model can be approximated to the band-tail-state emission model proposed by Eliseev et al. [Appl. Phys. Lett. 71, 569 (1997)]. (C) 2001 American Institute of Physics.

Photoluminescence and electroluminescence of (Gd2O3-Ga2O3): Ce thin film

A novel electroluminescence oxide phosphor (Gd2O3-Ga2O3):Ce has been prepared by electron beam evaporation. The emission peaks of photoluminescence lie at 390nm and a shoulder at 440nm. However, the electroluminescence of the (Gd2O3-Ga2O3):Ce thin film have four emission peaks at 358nm, 390nm, 439nm and 510nm, respectively. The optical absorption of (Gd2O3-Ga2O3):Ce thin film and the photoluminescence of composite materials with various ratios of Ga2O3/(Gd2O3+Ga2O3) have also been described to investigate the origin of emission of photoluminescence and electroluminescence.

一种无线传感器网络中事件区域检测的容错算法

特殊环境中的事件区域检测是无线传感器网络的一种重要应用.由于传感器的错误会导致事件区域检测的不准确,所以相关的容错算法成为近年来的研究热点.已有研究工作都仅考虑了事件的空间相关性,通过相邻传感器之间的数据交换实现容错.文中从事件的空间相关性和时间相关性入手,提出了一种以局部检测为主的分布式事件区域检测算法.该算法通过检验传感器本地采样值构成的时间序列与事件随机过程统计特征的符合程度实现容错.算法分析的结果表明,该算法可以减少传感器之间的数据交换,从而有效地利用传感器的能量.模拟实验表明,当有10%的传感器发生错误时,该算法可以检测到93%的事件区域和88%的错误传感器.

一种高效的RDF图模式匹配算法

随着越来越多的信息被表示为RDF格式，如何高效地对RDF信息进行分发和过滤成为一个重要的问题．在语义Web环境下的信息分发系统中，输入的RDF信息需要和大量的用户订阅条件进行匹配，而用户的订阅条件可以被表示为RDF图模式．根据RDF图的特点，并对其增加了一些约束．设计了一种新的RDF图模式匹配算法．实验结果表明，该算法的匹配效率远远高于传统的图模式匹配算法．