首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
白洋淀浮游植物现状   总被引:10,自引:0,他引:10  
本文研讨了白洋淀重新蓄水后的浮游植物种类组成、数量分布与环境理化因子的关系,并依据多样性指数标准及指示种评价了白洋淀水质。1990年5月至1992年7月共鉴定到浮游植物8门,10纲,25自,50科,135属,398种,20变种。其中绿藻门65属191种8变种;硅藻门27属98种11变种;蓝藻门27属68种;隐藻门最少,仅有1属4种。白洋淀重新蓄水后浮游植物的数量分布以南刘庄最高,年沟值973.7x10 ̄4个/L;韩村最低,仅26.0x10 ̄4个/L。白洋症水样含浮游植物细胞密度春季最高,平均值为411.4x10 ̄4个/L,并以绿藻占绝对优势,平均值为353.2x10 ̄4个/L,占春季总量的85.85%,占绿藻全年总量的40.62%。不同淀区浮游植物种类组成的多样性指数在0.617—0.919(Simpson’sindex)和3.190—4.501(Shannon-Weaver’sindex)范围。  相似文献   

2.
引水和疏浚工程对杭州西湖轮虫群落结构的影响   总被引:4,自引:0,他引:4  
1990年、1995年和2003年观察了引水和疏浚工程支配下浅水、富营养化杭州西湖(Ⅰ-Ⅲ站)浮游轮虫的群落变化,研究内容包括种类组成和优势种演变、密度和生物量、以及生物多样性指数。西湖轮虫的第一优势种由引水前的螺形龟甲轮虫(Keratella cochelearis),引水后演变为1990年的裂痕龟纹轮虫(Anuraeopsis fissa)和1995年的暗小异尾轮虫(Trichocerca pusilla),疏浚工程后针簇多肢轮虫(Polyarthra trigla)上升为西湖轮虫第一优势种。不同采样站中,引水促使了Ⅰ站(进水口)轮虫优势种的演变和轮虫丰度的显著下降,并使轮虫生物量与水体叶绿素a含量之间的相关性最强(相关系数达0.7080,p〈0.01);疏浚促使了Ⅲ站(出水口)轮虫优势种的演变和抑制了轮虫丰度的快速增加,并使轮虫生物量与水体高锰酸盐指数之间的相关性最强(相关系数0.5440,p〈0.25)。Ⅰ-Ⅲ站轮虫生物量与水体综合营养状态指数之间均有显著的正相关性。随着引入西湖水量的显著减少、疏浚工程的实施和西湖自身富营养化的推进,Ⅰ站和Ⅱ站轮虫的丰度急剧增加,生物多样性持续下降,Ⅲ站轮虫丰度增加较缓。这预示着Ⅰ站和Ⅱ站水体的富营养化进程快于Ⅲ站。  相似文献   

3.
通过2012年4次对珠江三角洲河网浮游动物的生态调查,研究该水域浮游轮虫的群落结构,包括种类组成、优势种、生物量及多样性等的时空分布,探讨了浮游轮虫群落结构与环境因子的相关关系,并阐析了浮游轮虫的聚群结构.结果表明: 共检出53种浮游轮虫.优势种类的季节演替及空间变化明显,针簇多肢轮虫占有较大优势.从季节变化来看,枯水期密度及生物量均大于丰水期,丰水期的生物多样性指数和均匀度要高于枯水期,浮游轮虫生物量和多样性的季节间差异显著;从空间分布来看,平均密度及平均生物量均呈现自西南向东北升高的趋势,最大密度及生物量均出现在市桥,而生物多样性指数和均匀度指数的空间变化趋势则相反,最高值均出现在青岐,浮游轮虫密度在各调查站位间差异显著,生物量及多样性在各调查站位间的差异不显著.浮游轮虫的密度与生物量、生物多样性指数与均匀度指数呈显著正相关,多样性与生物量呈显著负相关,生物多样性指数和均匀度指数随着生物量的增加显著降低.在不同季节,浮游轮虫密度与水温、pH、溶解氧、叶绿素a含量及总磷、总氮等环境因子密切相关.根据浮游轮虫密度对调查站位进行聚群分析得出5种聚群结构,说明相应调查站位的水质状况有显著差异.  相似文献   

4.
滆湖轮虫群落结构与水质生态学评价   总被引:6,自引:0,他引:6  
研究了浅水湖泊--滆湖的轮虫群落结构,并用轮虫污染指示种类、E/O值、QB/T值和生物多样性指数评价滆湖的水质和营养状况.在两周年的研究中,共发现轮虫69种,污染指示轮虫39种.优势种为萼花臂尾轮虫(Brachionua calyciflorus)、前节晶囊轮虫(Asplanchna priodonta)、针簇多肢轮虫(Polyarthra trigla)、长三肢轮虫(Filinia longiseta)和裂足臂尾轮虫(B.diversicornis).轮虫密度年平均值为1584 ind./L,生物量年平均值为5.982 1 mg/L.密度秋季最高,生物量夏季较高.轮虫物种多样性较低,多样性指数与其密度及生物量正相关.滆湖三个生态功能区轮虫的种类相似;湖区北部与中部的轮虫现存量差异不显著,与南部的差异显著,中部与南部间差异极显著.根据指示生物法、生物指数法和多样性指数法评价滆湖水质及营养类型,涌湖为富营养型.  相似文献   

5.
长江仪征-崇明段的轮虫调查   总被引:3,自引:0,他引:3  
作者于1988年5月-1990年7月对长江下游仪征-崇明江段的轮虫进行了调查,发现轮虫103种,平均密度15.6个/升,平均生物量0.0131毫克/升。各江段轮虫的种类组成及数量分布差异较大,这与长江口复杂多变的环境有关,其中盐度是造成这种差异的主要因素。  相似文献   

6.
作者于1988年5月-1990年7月对长江下游仪征-崇明江段的轮虫进行了调查,发现轮虫103种,平均密度15.6个/升,平均生物量0.0131毫克/升。各江段轮虫的种类组成及数量分布差异较大,这与长江口复杂多变的环境有关,其中盐度是造成这种差异的主要因素。  相似文献   

7.
中麻黄悬浮培养体系的建立   总被引:5,自引:1,他引:4  
本文用中麻黄无菌苗为外植体,其切段培养在附加2mg/L2,4-D和0.5mg/L 6 BA的MS培养基上,全部脱分化形成白色疏松愈伤组织。愈伤组织继代培养于MS+0.5mg/L2,4-D+0.2mg/L6BA+0.2mg/L NAA+4%蔗糖的培养某上。以继代培养愈伤组织为材料进行悬浮培养,培养基为附加0.2mg/L2,4-D+0.1mg/L6BA+0.1mg/LNAA+2%蔗糖的MS液体培养基,得到分散性好,细胞形状接近圆形,细胞大小均一,细胞团多由2-30个细胞组成的悬浮培养体系。第三代悬浮培养细胞增长率为0.35g·fw/20ml·d,细胞有丝分裂指数为11.2%。条件培养和高密度接种可缩短延迟期,条件培养不能提高分裂指数,1g/10ml接种密度可使分裂指数提高至21.2%。  相似文献   

8.
高山红景天细胞悬浮培养过程中3mg·L^-16-BA,0.3mg·L^-1NAA,60mmol·L^-1氮源、0.5 ̄1.25mmol·L-1KH2PO4和20mg·L^-1蛋白胨,较适合于细胞生长和红景天苷的积累。在适宜的接种量下细胞培养24d后,生物量达14.04g·L^-1,干细胞中红景天苷含量为5.66mg·g^-1。  相似文献   

9.
月光花素对彩叶芋愈伤组织细胞生长和分化的影响   总被引:2,自引:0,他引:2  
在含有NAA0.2mg/L,2.4-D0.2mg/L的MS基础培养基中添加月光花素培养彩叶芋愈伤组织,结果显示,低浓度的月光花素能促进愈伤组织生长,高浓度则有明显的抑制作用,最适浓度为1.0 ̄2.0mg/L;培养两个月后,添加适宜浓度的月光花素(0.2 ̄2.0mg/L)的培养基能促进体细胞分化和植株再生,而高浓度处理和对照均未能分化出绿苗,表明适宜浓度的月光花素在合适的各行其事纱剂量的协同作用下,  相似文献   

10.
影响枣试管苗生长分化的因素(简报)   总被引:8,自引:0,他引:8  
骏枣试管苗在生长与分化过程中,以MS培养基的营养水平,温度25 ̄27℃为适宜,外植体是茎段比茎端好,斜剪和斜插对生长分化有利,生长素为0.3 ̄0.5mg/L为宜,细胞分裂素(6-BA)以1 ̄1.5mg/L为宜,两者最佳配比为1:3。  相似文献   

11.
12.
13.
On the origin of the Hirudinea and the demise of the Oligochaeta   总被引:10,自引:0,他引:10  
The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.  相似文献   

14.
15.
16.
17.
18.
19.
Data on the ontogeny of the posterior haptor of monogeneans were obtained from more than 150 publications and summarised. These data were plotted into diagrams showing evolutionary capacity levels based on the theory of a progressive evolution of marginal hooks, anchors and other attachment components of the posterior haptor in the Monogenea (Malmberg, 1986). 5 + 5 unhinged marginal hooks are assumed to be the most primitive monogenean haptoral condition. Thus the diagrams were founded on a 5 + 5 unhinged marginal hook evolutionary capacity level, and the evolutionary capacity levels of anchors and other haptoral attachement components were arranged according to haptoral ontogenetical sequences. In the final plotting diagram data on hosts, type of spermatozoa, oncomiracidial ciliation, sensilla pattern and protonephridial systems were also included. In this way a number of correlations were revealed. Thus, for example, the number of 5 + 5 marginal hooks correlates with the most primitive monogenean type of spermatozoon and with few sensillae, many ciliated cells and a simple protonephridial system in the oncomiracidium. On the basis of the reviewed data it is concluded that the ancient monogeneans with 5 + 5 unhinged marginal hooks were divided into two main lines, one retaining unhinged marginal hooks and the other evolving hinged marginal hooks. Both main lines have recent representatives at different marginal hook evolutionary capacity levels, i.e. monogeneans retaining a haptor with only marginal hooks. For the main line with hinged marginal hooks the name Articulon-choinea n. subclass is proposed. Members with 8 + 8 hinged marginal hooks only are here called Proanchorea n. superord. Monogeneans with unhinged marginal hooks only are here called Ananchorea n. superord. and three new families are erected for its recent members: Anonchohapteridae n. fam., Acolpentronidae n. fam. and Anacanthoridae n. fam. (with 7 + 7, 8 + 8 and 9 + 9 unhinged marginal hooks, respectively). Except for the families of Articulonchoinea (e.g. Acanthocotylidae, Gyrodactylidae, Tetraonchoididae) Bychowsky's (1957) division of the Monogenea into the Oligonchoinea and Polyonchoinea fits the proposed scheme, i.e. monogeneans with unhinged marginal hooks form one old group, the Oligonchoinea, which have 5 + 5 unhinged marginal hooks, and the other group form the Polyonchoinea, which (with the exception of the Hexabothriidae) has a greater number (7 + 7, 8 + 8 or 9 + 9) of unhinged marginal hooks. It is proposed that both these names, Oligonchoinea (sensu mihi) and Polyonchoinea (sensu mihi), will be retained on one side and Articulonchoinea placed on the other side, which reflects the early monogenean evolution. Except for the members of Ananchorea [Polyonchoinea], all members of the Oligonchoinea and Polyonchoinea have anchors, which imply that they are further evolved, i.e. have passed the 5 + 5 marginal hook evolutionary capacity level (Malmberg, 1986). There are two main types of anchors in the Monogenea: haptoral anchors, with anlages appearing in the haptor, and peduncular anchors, with anlages in the peduncle. There are two types of haptoral anchors: peripheral haptoral anchors, ontogenetically the oldest, and central haptoral anchors. Peduncular anchors, in turn, are ontogenetically younger than peripheral haptoral anchors. There may be two pairs of peduncular anchors: medial peduncular anchors, ontogentically the oldest, and lateral peduncular anchors. Only peduncular (not haptoral) anchors have anchor bars. Monogeneans with haptoral anchors are here called Mediohaptanchorea n. superord. and Laterohaptanchorea n. superord. or haptanchoreans. All oligonchoineans and the oldest polyonchoineans are haptanchoreans. Certain members of Calceostomatidae [Polyonchoinea] are the only monogeneans with both (peripheral) haptoral and peduncular anchors (one pair). These monogeneans are here called Mixanchorea n. superord. Polyonchoineans with peduncular anchors and unhinged marginal hooks are here called the Pedunculanchorea n. superord. The most primitive pedunculanchoreans have only one pair of peduncular anchors with an anchor bar, while the most advanced have both medial and lateral peduncular anchors; each pair having an anchor bar. Certain families of the Articulonchoinea, the Anchorea n. superord., also have peduncular anchors (parallel evolution): only one family, the Sundanonchidae n. fam., has both medial and lateral peduncular anchors, each anchor pair with an anchor bar. Evolutionary lines from different monogenean evolutionary capacity levels are discussed and a new system of classification for the Monogenea is proposed.In agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. EditorIn agreeing to publish this article, I recognise that its contents are controversial and contrary to generally accepted views on monogenean systematics and evolution. I have anticipated a reaction to the article by inviting senior workers in the field to comment upon it: their views will be reported in a future issue of this journal. Editor  相似文献   

20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号