Cells of the connective tissue differentiate and migrate into pollen sacs

In angiosperms, archesporial cells in the anther primordium undergo meiosis to form haploid pollen, the sole occupants of anther sacs. Anther sacs are held together by a matrix of parenchyma cells, the connective tissue. Cells of the connective tissue are not known to differentiate. We report the differentiation of parenchyma cells in the connective tissue of two Gordonia species into pollen-like structures (described as pseudopollen), which migrate into the anther sacs before dehiscence. Pollen and pseudopollen were distinguishable by morphology and staining. Pollen were tricolpate to spherical while pseudopollen were less rigid and transparent with a ribbed surface. Both types were different in size, shape, staining and surface architecture. The ratio of the number of pseudopollen to pollen was 1:3. During ontogeny in the connective tissue, neither cell division nor tetrad formation was observed and hence pseudopollen were presumed to be diploid. Only normal pollen germinated on a germination medium. Fixed preparations in time seemed to indicate that pseudopollen migrate from the connective tissue into the anther sac.     

环保"民声热线"聚焦五大热点

8月8日，广东省环保局局长李清第一次坐在了广东省电台的直播大厅，围绕百姓关心的环境问题接受咨询与投诉。8月22日，他再次上线，集中解答了珠江整治与水环境的有关问题。此外，8月15日和8月29日，副局长王子葵、陈光荣也相继出现在直播间。     

加强高校党风廉政建设努力营造和谐育人环境

首先从巩固党的执政地位、完成党的执政使命,培养中国特色社会主义事业合格建设者和可靠接班人,构建社会主义和谐社会方面论述了加强高校党风廉政建设的重要意义.在此基础上,将个别高校在党风廉政建设中存在的主要问题归纳为商业腐败、人事腐败、学术腐败、证书腐败、评估腐败等五大方面.并进一步指出:要有效治理高校党风政风中存在的问题,高校党委、纪委应在加强学习,提高认识,注重教育,完善制度,强化监督等方面做出不懈努力.     

呼和浩特市发电厂污染物综合治理与资源化利用技术研究

本文以呼市发电厂废水、粉尘和灰场污染治理为例，研究制定发电厂粉煤灰综合治理与回收利用技术方案、旧灰场的生态工程建设和冲灰水的回收利用方案，通过污染物治理，废水的利用率达到85％，粉煤灰处理后的产草量和年利用率为98％，灰场的植被覆盖度达到97％，通过治理使发电厂的污染物排放量减少，废弃物资源得以利用，灰场变成环境优美的生态旅游区，为我国电厂的治理工作提供一个切实可行的科学依据。     

提高氧化沟法城市污水处理系统除磷效果探讨

根据厦门市集美污水处理厂的实际生产情况,通过对除磷原理的分析,从溶解氧、泥龄、回流及进水方式3个方面出发,在实际生产中进行调控测算,从而找出提高污水处理系统除磷效果的有效方法。     

Insights into reactive oxygen species formation induced by water-soluble organic compounds and transition metals using spectroscopic method

Ambient particulate matter (PM) can cause adverse health effects via their ability to produce Reactive Oxygen Species (ROS). Water-Soluble Organic Compounds (WSOCs), a complex mixture of organic compounds which usually coexist with Transition Metals (TMs) in PM, have been found to contribute to ROS formation. However, the interaction between WSOCs and TMs and its effect on ROS generation are still unknown. In this study, we examined the ROS concentrations of V, Zn, Suwannee River Fulvic Acid (SRFA), Suwannee River Humic Acid (SRHA) and the mixtures of V/Zn and SRFA/SRHA by using a cell-free 2′,7′-Dichlorodihydrofluorescein (DCFH) assay. The results showed that V or Zn synergistically promoted ROS generated by SRFA, but had an antagonistic effect on ROS generated by SRHA. Fluorescence quenching experiments indicated that V and Zn were more prone to form stable complexes with aromatic humic acid-like component (C1) and fulvic acid-like component (C3) in SRFA and SRHA. Results suggested that the underlying mechanism involving the fulvic acid-like component in SRFA more tending to complex with TMs to facilitate ROS generation through π electron transfer. Our work showed that the complexing ability and complexing stability of atmospheric PM organics with metals could significantly affect ROS generation. It is recommended that the research deploying multiple analytical methods to quantify the impact of PM components on public health and environment is needed in the future.     

钢渣湿法脱硫试验研究

以某厂钢渣为吸收剂,以旋流板塔为吸收器,对湿法脱硫进行了试验研究。通过分析钢渣脱硫前后的化学成分变化,以及试验脱硫率随反应过程的变化,提出了钢渣湿法脱硫的反应机理。同时,试验研究了液气比、进气SO_2浓度、浆液浓度等主要参数对脱硫率的影响,以及加添加剂的效果。试验结果表明,通过合理的设计和适当的操作,可使钢渣湿法应用于中低脱硫率(50％～70％)的场合,以取得综合治理、以废治废的效果。     

The functionality of female reciprocal calls in the Iberian midwife toad (<Emphasis Type="Italic">Alytes cisternasii</Emphasis>): female-female acoustic competition?

Female midwife toads (genus Alytes) emit highly variable reciprocal calls of unclear function prior to and during courtship. In some species, female-female competition, expressed as physical fighting, has been reported. Males of Majorcan midwife toads (Alytes muletensis) show phonotactic response to female calls, and females of Iberian midwife toads (Alytes cisternasii) respond differently according to the male call characteristics. In this study, I test the hypothesis of female-female acoustic competition as an additional function of female reciprocal calls. Playback tests indicate that female calls are not clearly involved in female acoustic competition in the Iberian midwife toad, therefore female calls could be directed at males rather than towards competitive females.     

重庆三峡库区农林复合经营可持续发展研究

提出重庆三峡库区实施农林复合经营的重要性及其可持续发展理论和结构类型，并针对存在的问题，提出农林复合经营可持续发展对策。