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.     

神府东胜矿区生态环境问题及对策

在调查研究分析的基础上，从分析矿区生态环境影响的特点入手，针对矿区开发建设中存在的主要生态问题，提出了保护生态环境的对策和措施，对于矿区的生态环境保护和可持续发展具有一定的参考价值。     

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。     

环境物质拟除虫菊酯毒理学研究进展

拟除虫菊酯作为一种重要的合成杀虫剂,在人们的生产生活中有着广泛的应用,但同时其毒理学问题也越来越引起人们的注意,许多学者对此进行了深入的研究,在此研究基础上,从对动物的神经毒性、生殖毒性和生理生化毒性三个方面,对拟除虫菊酯的毒理学研究进展作一综述.     

访国家环保总局局长解振华:坚持改革创新努力健全环保长效机制

明朗的九月,迎来了《环境保护》杂志的全新改版。秉承着“为中国环境保护事业服务”这一办刊方针,我们以彰显政策权威性作为改刊宗旨。在改版的开篇,有幸邀请到国家环境保护总局解振华局长做客“访谈录”,与我们共同探讨走过30多年历程的环保事业的今天和明天。在采访解局长的过程中,我能切身感受到他对中国环境现状的忧虑和操劳,也能深刻体会出他对环保事业美好未来的执著和坚定。遗憾的是,面对中国环保这个庞大而艰深的话题,繁忙的解局长能给我们的时间实在太少。在匆匆结束了此次访谈之后,我将精彩的谈话内容记录于此,与您共享。     

辽东湾海冰晶体结构及其内部叶绿素的初步研究

本文介绍了１９９６年冬季首次辽东湾生态环境调查中的海洋背景条件。扼要地阐述了辽东湾海冰一般概况，分析辽东湾冰样晶体结构、存储条件及其与冰内和冰下海水叶绿素之间的关系。辽东湾冰内叶绿素符合其它结冰海区的一般规律。根据辽东湾冰层底部实测盐度变化规律阐明海冰对冰下海水营养盐的贡献。最后对深入开展结冰海区生态环境调查工作的技术、侧重点和意义做了讨论。     

废水中对—氨基苯酚的电位溶出法测定

采用Nafion修饰电极,以微分计时电位溶出法分析测定废水中对—氨基苯酚(PAP)。在选定的条件下,PAP的测定范围在1.0μ～0.5mmol/l之间;最低检测浓度为0.1μmol/l;标准偏差为1.6％:方法的回收率为92.5％～96.5％。     

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.     

公害民事责任三论

当今，公害已成为公众十分关注的社会问题之一。为维护我国公民的合法权益，我国环境保护法律体系中，对公害造成的社会性危害作了具体规定，文章对民事责任基本从三方面作了比较系统完整的探讨。公害民事责任的法律规定。公害民事责任的特点，公害民事责任与资源破坏民事责任的关系，在公害民事责任与一般民事责任关系的分析中，阐述了追公害民事责任的法律依据和公害民事责任是一种特殊的侵权的民事责任的特性。