Distribution and diversity of <Emphasis Type="Italic">Candida tropicalis</Emphasis> strains in different marine environments

1089 strains of yeasts were obtained from seawater,sea sediments,mud of sea saltems,guts of marine fishes,mangrove plants and marine algae.The results of routine identification and molecular analysis methods show that 44 strains among the marine yeasts obtained in this study belong to Candida tropicalis,which may indicate its wide distribution in different environment,especially in the tropical and subtropical marine environment.The wide distribution of C.tropicalis indicates that it may play an importam role in marine environment and the marine environment in turn is a good source for obtaining C.tropicalis.     

15种植物提取液对丁鱼岁幼鱼引诱作用的初步研究

鱼类对植物提取液产生趋向行动(taxis或chemotaxis)属于生态生物化学的范围,这类研究具有广泛的科学和实践意义[1].国内用动植物提取液或提取物研究过南方鲶幼鱼、鲤鲫鱼、草鱼鱼种、罗非鱼的摄食行为[2～5],国外用氨基酸作为诱食剂[6].     

Species diversity and population status of threatened plants in different landscape elements of the Rohtang Pass,western Himalaya

This paper highlights the quantitative estimates of plant species diversity and ecosystems of the Rohtang Pass,which is one of the most preferred visiting spots by tourists in Himachal Pradesh （H.P.）,India. In spite of high pressure of anthropogenic activities,the Rohtang Pass still harbours a variety of flowering plants with economic value,including various medicinal herbs. In order to observe species diversity in different landscape elements （LSEs）,ground surveys were conducted in nine unique LSEs within the elevation range between 3624 m and 4332 m. Plant community structure in each LSE was studied using stratified random sampling where a total 56 quadrats of 1 m^2 in size for herbs and 7 quadrats of 25 m^2 for shrubs were made. Of the total 50 plant species belonging to 15 families recorded in different random quadrats,24 species were found of medicinal value. Maximum species richness （18） and value of Shannon diversity （H＇=2.2648） were observed on northeast-facing slope in Picrorhiza kurrooa dominated LSE in moist area,followed by Rheum emodi LSE （species richness = 17 and H＇ = 2.4141） distributed on south-facing slope. Maximum values of species richness and Shannon diversity in Rheum emodi LSE were observed between 8 ～ 12 and 1.4797 ～ 2.1911,respectively. Rhododendron anthopogon dominated LSE on northwest-facing slope was found least diverse in terms of species richness where the Simpson index of dominance （D） was 0.4205. The species were equal in abundance in P. kurrooa LSE on east-facing slope and Pleurospermum candollii LSE on north-facing slope,showing the maximum similarity in terms of species distribution between the two LSEs. Low turnover of species across common LSEs gives an idea regarding their limited distribution. Five species of threatened category according to the IUCN criteria were observed in seven LSEs. The largest population of threatened medicinal plants was recorded on northeast and northwest-facing slopes where population density of Bergenia stracheyi （     

Bloom forming species of phytoplankton in two coastal waters in the Southeast coast of India

The results of an investigation carried out during June 2005 to May 2007 on bloom-forming phytoplankton species composition and abundance in the Parangipettai and Coleroon coastal waters(Southeast coast of India) are reported.Air and surface water temperatures(℃) varied from 25.1 to 30.1 and 24.5 to 28.5,respectively,in the former waters and from 25.5 to 31.2 and 25.0 to 29.3 in the latter waters.The respective salinities varied from 6.0 to 28.5 and 5.0 to 33.1 and the respective pH ranged between 7.0 and 8.3 and 7.2 and 8.3.Correspondingly,the dissolved oxygen content varied from 3.1 to 7.5 and 3.1 to 7.9 mgL-1 while the light extinction coefficient(LEC) values ranged between 3.1 and 10.1 and 1.8 and 11.0.The content ranges of inorganic nutrients,i.e.,nitrate,nitrite,phosphate and silicate(μmolL-1),in the Parangipettai and Coleroon coastal waters were:6.5-27.0;1.0-8.9;0.1-3.0 and 15.0-140 and 10.1-23.4;1.2-8.9;0.2-3.1 and 55-125 respectively.The chlorophyll a contents in both waters ranged from 2.0-7.5 μgL-1.Presently,124 phytoplankton species representing different classes were recorded in the Coleroon coast,viz,Bacillariophyceae(77);Dinophyceae(19);Cyanophyceae(15);Chlorophyceae(10) and Chrysophyceae(3),whereas 117 phytoplankton species were recorded in the Parangipettai coast,viz,Bacillariophyceae(66);Dinophyceae(22);Cyanophyceae(19);Chlorophyceae(7) and Chrysophyceae(3).The phytoplankton cell abundance in the Parangipettai and Coleroon coastal waters varied from 290 to 111662 and 140 to 132 757 cells L-1,respectively,with peak diversity(3.38 and 3.52 bits ind-1.) recorded in summer.The maximum abundance occurred in summer coinciding with the stable hydrographical conditions.The seasonal distribution and abundance of phytoplankton are discussed in relation to hydrographical parameters.Totally 31 and 24 species of phytoplankton were found to be bloom-forming in the Parangipettai and Coleroon coastal waters,respectively.Presently Trichodesmium bloom was also observed,which appeared at the 10 fathom level of the coastal water and quickly spread to the marine zone of the Vellar estuary and near the mouth region of the mangrove waters.The Parangipettai and Coleroon coastal waters are subject to long term fluctuations in physico-chemical conditions depending upon the seasonal tidal range and freshwater influx,resulting in a continuous exchange of organic,inorganic,plant and animal matters.     

居室最适合放置及不宜放置的植物

植物是人类的朋友,人们喜欢用它们来装饰居室,有利于身心健康。最近,美国航空航天局的科学家们发现,常青的观叶植物以及绿色开花植物中,很多都有消除建筑物内有毒化学物质的作用。此次研究还发现,植物不光是靠叶子吸取物质,植物的根以及土壤里的细菌在清除有害物方面都功不可没     

Phytoplankton Community Dynamics in West Lake After Drawing Water from the Qiantang River

1INTRODUCTIONTheWestLake ( 30°1 5′N ,1 2 0°1 6′E)isasmallshallowlakeinthewesternpartofHangzhouCityinthesoutheasterncoastalareaofChina.Thelakeissur roundedonthreesidesbyhills ;andisfamousforitspicturesquesceneryandinterfusionofhillsandwaterbodies.Thesurfaceareaisabout 5 .66km2 andmeandepthis 1 .8m .Beforethe 1 95 0s ,thelakewaterwascleanandmacrophytesgrewveryluxuriantlyinthelit toralareasofthelake .In 1 95 2 ,WestLakewasdredgedand 70 0× 1 0 4m3 mudwasremovedfromthebottomofthelake …     

植物生长调节剂对绿色巴夫藻生长的影响

研究了二种植物生长调节剂对绿色巴夫藻 ( Pavlova viridis)的生长、叶绿素含量和干重的影响。结果表明 ,在试验浓度范围内 ,2 ,4— D对绿色巴夫藻生长的影响在培养早期比后期明显 ,最适浓度为 0 .1 m g/L ;6-BA质量浓度≥ 1 mg/L时对绿色巴夫藻有致死作用 ,质量浓度为 0 .1～ 0 .8mg/L时 ,对绿色巴夫藻的生长有促进作用 ,促进生长的最适质量浓度为 0 .5mg/L。在一定浓度范围内 ,二种植物生长调节剂都可促进绿色巴夫藻的生长 ,提高叶绿素含量 ,增加试验藻的干重。     

浙江晚泥盆世的石松类(Lycopodiales)化石

本文描述了萧山虎山和长兴泗安晚泥盆世地层中的石松类化石,共有6个属9个种,其中包括1个新属和3个新种,分别:SpinolepidodendronhangzhouenseGen.etsp.nov,SublepidodendronXianshanensesp.nov,Eolepi-dodendronhushanensesp.nov.。认为浙江晚泥盆世植物化应归于以Leptopnloeumrhombicum-Sublepidodendronxi-aoshanense—Xihuphyllummegalofolium为代表的组合。     

纳米二氧化钛分离富集和ICP-AES测定水样中Cr（Ⅵ）和Cr（Ⅲ）

铬是环境污染及动植物生长发育最重要的元素之一，铬的毒性及生物可用性不取决于铬的总量，而是取决于存在的形态，铬的价态不同，对人体作用迥然不同。适量的Cr（Ⅲ）为人体所必需，是维持体内正常的糖．月旨肪，蛋白质代谢的必需元素，而Cr（Ⅵ）则对人体有高度毒性，具有干扰生物酶活性，致癌，致突变等作用。因而在环境水质监测中，不仅要检测样品中铬的总量，同时也要分别检测各种价态铬的含量．对Cr（Ⅵ）Cr（Ⅲ）的测定已报道的有离子交换法，溶剂萃取法，固相萃取法，共沉淀法，电化学法等。但这些方法分离富集手续繁琐，时效低，且大多数方法基于测定Cr（Ⅵ）和总铬量，需要从Cr（Ⅲ）到Cr（Ⅵ）的转化步骤。     

土壤中有效钼的快速测定

钼是植物所必需的微量元素，只有Mo^6＋是对植物有效的。土壤中的钼可分为四部分：水溶性的（含量极少，不易测量）；交换性的（被土壤粘粒矿物或铁锰的氧化物吸附的MoO^2- 4离子，对植物有效）；难溶性的（对植物无效）和有机结合态（与土壤有机质结合的钼，随着有机质矿化，可以被释放出来为植物所吸收利用）。能被植物吸收的钼，可用草酸——草酸铵溶液浸提，其含量一般为0．05～0．5（10^-6），催化极谱的检出限和准确度能满足测定要求。