首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 31 毫秒
1.
There are species of Macromitrium in Guizhou province China. Among them, 2 species are endemic species, M.cavalerier Card &; Ther. and M.fortu natii Card &; Ther. During a recent re-examination of some Macromitrium specime ns from this region. A taxon closely related to species of the M. ferriei Card &; Ther. was found to be different from any known species of Macromitrium and is described here as a new species.......  相似文献   

2.
Croesia is a small genus of Subfamily Tortricidae, Tribe Tortricini, established by H?bner in 1825. 27 species have been recorded in the world; except 3 species in North America and one species in Europe, the rest 23 species are all distributed in Asia. Among them, 9 species are recorded in China. We have had an opportunity of examining 11 species occurring in China, of which 5 are  相似文献   

3.
The present article tests the following general assumption:plant taxa with different specializations towards mycorrhizal interactions should have different root syndromes.Roots of 61 species common in boreal zone were studied:16 species of Poaceae,24 species of Cyperaceae,14 species of Orchidaceae,and7 species of Iridaceae.Using a fixed material of 5 individuals of each species,the following was determined:number of orders of branching roots;transverse dimensions of root,stele and cortex;number ...  相似文献   

4.
Dermal and hypodermal anatomical features of 70 species representing 21 genera of North American Cactoideae were studied. Results show that all species examined have parallelocytic stomata and anticlinal wall surface varies from straight to undulate. Cuticle thickness is mostly narrow (1–10 μm) contrary to the general opinion that cuticle is thick in most cacti; however, few species such as Ariocarpus fissuratus and several species of Pachycereus show a distinctive thick cuticle. More than 80% of the species studied have a single-layered epidermis. Papillae occur in eight species belonging to four genera. Notable papillae are a feature shared by all members of Peniocereus subg. Peniocereus. Other species show a bullate surface produced by irregular patches of secondary epidermal cell divisions. Commonly, the hypodermis is composed of more than two cell layers with distinctive collenchymatous walls as reported in many South American species. Silica bodies, prismatic crystals, druses, sphaerocrystals, and tannins are the most common cellular inclusions that distinguish several genera and appear to have taxonomic value. However, a more thorough search in species of Cephalocereus, Coryphantha, Echinocereus, Mammillaria, Neobuxbaumia, Pilosocereus, and Turbinicarpus is needed to support the previous assertion. Electronic Publication  相似文献   

5.
Shenzhen was a famous typical rapid-urbanization city in China, and this study compares plant species diversity in urban parks from the start of urbanization through 2011. Results show that the plant species biodiversity increased rapidly: the rate changed from 140% to 980% and the average increasing rate was 406.90%, but only 12.59% of plants spread into the park naturally. Shrubs had the highest rate; with change increasing from 20.70% to 43.54%, they replaced trees to become the dominant type. The biodiversity of native plants also increased, but their proportion relative to all species had declined. The homogenization of plant species in the parks increased; more than half of the plant species (62.24%) are located in 5–7 parks at once now, compared with 65.52% of species located in only 2–3 parks at the start of the study. The increase of species was faster than the increase of families; many new species planted belong to a few specific families. The ratio of species to families declined from 0.40 to 0.32. Results indicate that the rapid increase of plant species diversity as well as their homogenization happened in the initial stage of urbanization, and so rapid urbanization might be the major factor in the changes in plant species diversity in municipal parks. Rapid urbanization was an important cause of change in plant species diversity.  相似文献   

6.
Wan R J  Zhou F  Shan X J  Sun S 《农业工程》2010,30(3):155-165
During June, August and October 2006, there were three multi-disciplinary surveys carried out in the Changjiang River estuary and its adjacent waters (122°00′–125°00′E, 27°50′–34°00′N) by R/V Beidou to study the species composition and abundance of ichthyoplankton (including fish eggs, larvae and juveniles), the spatial distribution of fish spawning ground and their relationship with habitat factors. There were 29, 29 and 25 grid stations sampled in the three cruises, respectively. The ichthyoplankton samples were collected by horizontally towing with a macro-plankton net (mouth diameter 80 cm, length 270 cm, mesh size 0.50 mm) at the sea surface, and the towing speed was 3.0 n mile/h at each sampling station. The towing lasted for 10 min. After hauling for each station, habitat factors including temperature and salinity were measured by Sea Bird-25 CTD. Samples were preserved in 5% formaldehyde solution immediately after sampling for analysis in laboratory. Since the trawl speed could not be accurately evaluated due to the effects of ocean currents and wind-induced wave, the amount of ichthyoplankton was evaluated by actual number of the sampling haul in each station. Ichthyoplankton collected were divided into three categories: dominant species, important species and main species by the index of relative importance (IRI). There are 71 species (including 1200 fish eggs and 2575 fish larvae and juveniles) collected during 3 cruises and 59 species have been correctly identified to species level, which belongs to 50 genera, 37 families and 9 orders; while 5 species can only be identified to genera level, 1 species only identified to family level and 6 species identified to order level. These 59 species identified to species level and 5 species identified to genera level are divided into three ecological patterns, i.e., brackish water species, neritic water species and coastal water species. Warm water species have 34 species in those 59 species identified to species level, accounting for 57.63%, warm temperature species have 25 species, accounting for 42.37%. According to the analysis of IRI, the dominant species are Engraulis japonicus (in June and August, that is important species in October), Scomber japonicus (in August), and Johnius grypotus (in October) during the survey; important species are Cynoglossus joyneri (in June and August), Trichiurus lepturus (in June, August and October), Gonorhynchus abbreviatus (in August), Stolephorus commersonii (in October), Saurida undosquamis (in October) and Saurida elongate (in October), and main species have 12 species in June, 9 species in August and 10 species in October, respectively. The amount of fish eggs and larvae of the dominant species, important species and main species (28 species) are 97.50% and 97.13% of the total amount of fish eggs and larvae, respectively, which are the important composition of fish eggs and larvae in the Changjiang River estuary and its adjacent waters.
In June and August of 2006, if compared with that in corresponding months in 1986, there are great changes in the habitat factors especially for temperature and salinity in the investigating areas: high salinity water from off-shelf is much closer to the coastal areas which results in the dramatic increase of sea surface salinity during all three surveys. Sea surface temperature, on the other hand, decreases distinctively in June, but significantly increases in August. The run-off of the Changjiang River greatly reduced due to the long-term drought in summer 2006, which is responsible for the great changes of habitat factors in the Changjiang River estuary and its adjacent waters. The habitat of the Changjiang River estuary is greatly changed, which consequently has significant influences on the spawning, breeding and the spatial distribution of spawning ground of neritic water species, such as Sardinella zunasi, Thryssa kammalensis, Thryssa mystax, Setipinna taty and S. commersonii ect, and coastal water species, such as Ilisha elongate and Konosirus punctatus ect.  相似文献   

7.
Ye Y H  Lin S S  Wu J  Li J  Zou J F  Yu D Y 《农业工程》2012,32(5):221-226
Shenzhen was a famous typical rapid-urbanization city in China, and this study compares plant species diversity in urban parks from the start of urbanization through 2011. Results show that the plant species biodiversity increased rapidly: the rate changed from 140% to 980% and the average increasing rate was 406.90%, but only 12.59% of plants spread into the park naturally. Shrubs had the highest rate; with change increasing from 20.70% to 43.54%, they replaced trees to become the dominant type. The biodiversity of native plants also increased, but their proportion relative to all species had declined. The homogenization of plant species in the parks increased; more than half of the plant species (62.24%) are located in 5–7 parks at once now, compared with 65.52% of species located in only 2–3 parks at the start of the study. The increase of species was faster than the increase of families; many new species planted belong to a few specific families. The ratio of species to families declined from 0.40 to 0.32. Results indicate that the rapid increase of plant species diversity as well as their homogenization happened in the initial stage of urbanization, and so rapid urbanization might be the major factor in the changes in plant species diversity in municipal parks. Rapid urbanization was an important cause of change in plant species diversity.  相似文献   

8.
During June, August and October 2006, there were three multi-disciplinary surveys carried out in the Changjiang River estuary and its adjacent waters (122°00′–125°00′E, 27°50′–34°00′N) by R/V Beidou to study the species composition and abundance of ichthyoplankton (including fish eggs, larvae and juveniles), the spatial distribution of fish spawning ground and their relationship with habitat factors. There were 29, 29 and 25 grid stations sampled in the three cruises, respectively. The ichthyoplankton samples were collected by horizontally towing with a macro-plankton net (mouth diameter 80 cm, length 270 cm, mesh size 0.50 mm) at the sea surface, and the towing speed was 3.0 n mile/h at each sampling station. The towing lasted for 10 min. After hauling for each station, habitat factors including temperature and salinity were measured by Sea Bird-25 CTD. Samples were preserved in 5% formaldehyde solution immediately after sampling for analysis in laboratory. Since the trawl speed could not be accurately evaluated due to the effects of ocean currents and wind-induced wave, the amount of ichthyoplankton was evaluated by actual number of the sampling haul in each station. Ichthyoplankton collected were divided into three categories: dominant species, important species and main species by the index of relative importance (IRI). There are 71 species (including 1200 fish eggs and 2575 fish larvae and juveniles) collected during 3 cruises and 59 species have been correctly identified to species level, which belongs to 50 genera, 37 families and 9 orders; while 5 species can only be identified to genera level, 1 species only identified to family level and 6 species identified to order level. These 59 species identified to species level and 5 species identified to genera level are divided into three ecological patterns, i.e., brackish water species, neritic water species and coastal water species. Warm water species have 34 species in those 59 species identified to species level, accounting for 57.63%, warm temperature species have 25 species, accounting for 42.37%. According to the analysis of IRI, the dominant species are Engraulis japonicus (in June and August, that is important species in October), Scomber japonicus (in August), and Johnius grypotus (in October) during the survey; important species are Cynoglossus joyneri (in June and August), Trichiurus lepturus (in June, August and October), Gonorhynchus abbreviatus (in August), Stolephorus commersonii (in October), Saurida undosquamis (in October) and Saurida elongate (in October), and main species have 12 species in June, 9 species in August and 10 species in October, respectively. The amount of fish eggs and larvae of the dominant species, important species and main species (28 species) are 97.50% and 97.13% of the total amount of fish eggs and larvae, respectively, which are the important composition of fish eggs and larvae in the Changjiang River estuary and its adjacent waters.
In June and August of 2006, if compared with that in corresponding months in 1986, there are great changes in the habitat factors especially for temperature and salinity in the investigating areas: high salinity water from off-shelf is much closer to the coastal areas which results in the dramatic increase of sea surface salinity during all three surveys. Sea surface temperature, on the other hand, decreases distinctively in June, but significantly increases in August. The run-off of the Changjiang River greatly reduced due to the long-term drought in summer 2006, which is responsible for the great changes of habitat factors in the Changjiang River estuary and its adjacent waters. The habitat of the Changjiang River estuary is greatly changed, which consequently has significant influences on the spawning, breeding and the spatial distribution of spawning ground of neritic water species, such as Sardinella zunasi, Thryssa kammalensis, Thryssa mystax, Setipinna taty and S. commersonii ect, and coastal water species, such as Ilisha elongate and Konosirus punctatus ect.  相似文献   

9.
10.
Ranković B 《Mycopathologia》1997,139(3):157-164
From 1982 to 1996, in Serbia, 229 species of plants infected with powdery mildew were collected. Seventy-five species had hyperparasites of the genus Ampelomyces. Distribution analysis showed that hyperparasitism was greatest on plants from the families Asteraceae, Apiaceae and Fabaceae. Ampelomyces was not found on the family Poaceae. It was reported for the first time on the families Amygdalaceae, Cornaceae, Grossulariaceae, Plantaginaceae, Rhamnaceae and other 37 plant species. Hyperparasites of the genus Ampelomyces were found on 33 different species of fungi that are causal agents of powdery mildews. They are reported for the first time on nine species. Pycnidial size varied in the range 45–106 × 25.5–40.5 μm and conidia from 4.5–10.5 × 2.5–4.8 μm. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

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