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 15 毫秒
1.
The distribution, body composition, growth rate, and population structure of Unio terminalis were measured at different sites of Lake Kinneret (Israel). Maximum clam density was found on the muddy sand between 0.3–6 m depth. Clams were most abundant in the River Jordan inlet zone, where they showed the highest growth rate. This was probably related to both highest food availability and the highest density of fish hosting Unio glochidia in this area. U. terminalis in Lake Kinneret has a more massive shell and ash content as compared with the European Unio species. The annual P/B ratios of U. terminalis populations at different sites were similar and ranged within 0.17–0.18. The computated filtration capacity and energetic budget permit the assumption that the U. terminalis population plays a substantial role in removal of organic particles from the water in the Kinneret shallow inshore zone (up to 15 m depth), and in nutrient recycling.  相似文献   

2.
Fire-stimulated flowering has long been a subject of investigation in tropical grasslands and savannas. Still, speedy blooming (i.e. flowering in <24 h after fire) had only been recently described for a single species of Cyperaceae common in Cerrado open ecosystems. Here, we described two new species displaying this unique feature of producing flowers <24 h after fire, suggesting that this fast phenological response might be more common than previously thought. Rhynchospora confusa F.Ballard and Rhynchospora terminalis Nees ex Steud. var. terminalis are two widely distributed species in grasslands and savannas at Chapada dos Veadeiros (a World Natural Heritage by UNESCO). Yet, there is a paucity of herbarium collection for both species and no registration of the quick bloom after fire passage or other aspects of their ecology. Understanding the diversity of phenological patterns and vegetation responses to fire is key to uncovering the functioning and singularities of the tropical open ecosystems.  相似文献   

3.
As part of our study of the Acanthaceae of Costa Rica and from a phylogenetic study of Ruellia as a whole, we place R. barbillana and R. metallica in synonymy with R. terminalis. We discuss species limits of R. terminalis and provide a key that distinguishes it from close relatives including R. grantii, R. oaxacana, and R. phyllocalyx. Ruellia puri is put into synonymy with R. jussieuoides, and R. standleyi is synonymized with R. ochroleuca. Disjunct distributions characterize R. terminalis, R. jussieuoides, and R. ochroleuca, although this pattern is most extreme in R. ochroleuca. Phylogenetic analysis of DNA sequence data lends support to our synonymy decisions. New lectotypifications are provided for Arrhostoxylum achimeniflorum, Dipteracanthus puri, Dipteracanthus puri β angustifolius, Dipteracanthus puri γ gymnocladus, Lychniothyrsus ochroleucus, and Otacanthus pearcei .  相似文献   

4.
  • 1 Experiments on the influence of temperature (5–25°C) on morphology, life history and growth rate of Filinia terminalis and F. cf. pejleri were performed in replicated individual cultures with Oocystis sp. as food.
  • 2 Some morphological characteristics previously used for the identification of both species were found to be affected by temperature and also by life cycle stage. However, numbers of unci teeth were not affected.
  • 3 Body and setal lengths, life spans, all stages of development, and growth rates of both species decreased with increasing temperature.
  • 4 Offspring number per female of both rotifers was highest at 20°C. Maximum growth rate of F. terminalis was at 25°C, whereas that of F. cf. pejleri was at 20°C.
  相似文献   

5.
Summary Carbendazim is the fungitoxic ingredient of different fungicides. In our experiments it was used as a supplement to stage II (multiplication) media for the micropropagation ofCordyline terminalis andPrunus avium. The product can be autoclaved without any loss of activity and there is no degradation of the product over a normal culture period of 32 days. WithC. terminalis andP. avium no phytotoxic effect was revealed up to 160μg/ml. ForC. terminalis shoot height was reduced and the number of shoots smaller than 15 mm increased significantly. Presented in the Session-in-Depth Novel Plant Growth Regulators at the 1992 World Congress on Cell and Tissue Culture, Washington, DC, June 20–25, 1992.  相似文献   

6.
Sur les genres keratella,synchaeta, polyarthra et filinia d'un lac italien   总被引:2,自引:2,他引:0  
Agostino Parise 《Hydrobiologia》1961,18(1-2):121-134
Résumé On a considéré ici quelques formes des genres Keratella, Polyarthra, Synchaeta et Filinia. On a relevé, dans le lac de Nemi, deux races écologiques chez Keratella cochlearis, et une écologiques chez K. quadrata. Chez le gen. Polyarthra on a observé que l'on trouve, suivant l'hypothèse de l'introgression par Pejler (1956), bien plus fréquemment des formes hybrides que des formes typiques. Chez le gen. Synchaeta on a décrit en detail les mastax type tremula et type pectinata; on a exprimé l'opinion qu'il n'est pas possible de distinguer entre elles, par la structure du mastax, les formes S. tremula (ou truncata), S. kiting; S. oblonga et S. lakowitziana. Chez le gen. Filinia on pense qu'il soit possible de distinguer morphologiquement F. longiseta et F. terminalis, mais il est possible qu'à ces deux formes correspondent plusieures espèces.  相似文献   

7.
Characteristics of the flowering trees of Acacia terminalis may be interpreted as adaptations for bird pollination. Each leaf bears a single red nectary up to 12 mm long on its petiole. Nectaries show greatest secretory activity at flowering (max. 15 μl/nectary/day), and nectar was found only in the early morning. The nectar contains a mean of 16% sugars (max. >50%) and is hexose rich with 18 amino acids, especially glutamine and phenylalanine. Analyses of foraging dynamics and pollen loads from feathers of passerine birds further support this interpretation.  相似文献   

8.
Abstract

Several quantitative and qualitative seed characters of the seven European species of Erica sect. Loxomeria, Eremocallis and Brachycallis were studied. Two main seed types are found based on size and shape: regular ellipsoid or oblong seeds of ca. 0.4 mm for E. ciliaris and the E. tetralix group, and curved to kidney‐shaped seeds of 0.6–0.9 mm for E. cinerea, E. maderensis and E. terminalis. The testa surface in E. ciliaris is reticulate, with indented outer periclinal walls. Erica cinerea has inflated outer anticlinal walls. This character is exclusive for this species within the European (and nearby areas) species of the genus. The seeds of E. maderensis are similar to those of E. terminalis. According to seed morphology, the classical infrageneric classification, by which E. terminalis would be grouped with the E. tetralix group in sect. Eremocallis and E. maderensis in sect. Brachycallis with E. cinerea, is artificial.  相似文献   

9.
Summary Ipsilateral antennular dysfunction resulting from total unilateral eyestalk ablation in spiny lobsters does not occur when visual input is restricted by an opaque cap over one eyestalk, or when optic ganglia alone (eg. lamina ganglionaris, medulla externa, medulla interna) are removed. Antennular dysfunction appears only when connections between the most proximal of the four eyestalk ganglia, the medulla terminalis, and the remainder of the cerebral ganglia (brain) are interrupted. We conclude that neural processing of olfactory input from the antennule involves structures in the medulla terminalis.Contribution number 430 from the Bermuda Biological Station for Research, Inc. This work was supported by USPHS Grant NB-06017.  相似文献   

10.
In this paper some results of mud samples with regard to chironomid larvae populations are presented. These examination are important in view of the restoration measures to be taken in order to alleviate the eutrophication pressure. Filinia populations are very consistent in some years as 1969, 1972 and 1973. F. terminalis is dominant in the first months of the year but with the advent of warmer weather and disturbance of the mud layer it switches abruptly (within one week) to F. longiseta.Paper presented at the XXth SIL Congress, Copenhagen, 7–14 August 1977, under the heading Biological Observations in the Watersportbaan at Ghent, Belgium.  相似文献   

11.
Borreria terminalis Small is recognized as a species distinct fromS. verticillata L. and as an endemic to southern Florida and is transferred to the genusSpermacoce L. A new combination,S. terminalis (Small) Kartesz & Gandhi, is proposed, and a lectotype is designated.  相似文献   

12.
13.
Forty Klebsormidium strains isolated from soil crusts of mountain regions (Alps, 600–3,000 m elevation) were analyzed. The molecular phylogeny (internal transcribed spacer rDNA sequences) showed that these strains belong to clades B/C, D, E, and F. Seven main (K. flaccidum, K. elegans, K. crenulatum, K. dissectum, K. nitens, K. subtile, and K. fluitans) and four transitional morphotypes (K. cf. flaccidum, K. cf. nitens, K. cf. subtile, and K. cf. fluitans) were identified. Most strains belong to clade E, which includes isolates that prefer humid conditions. One representative of the xerophytic lineage (clade F) as well as few isolates characteristic of temperate conditions (clades B/C, D) were found. Most strains of clade E were isolated from low/middle elevations (<1,800 m above sea level; a.s.l.) in the pine‐forest zone. Strains of clades B/C, D, and F occurred sporadically at higher elevations (1,548–2,843 m a.s.l.), mostly under xerophytic conditions of alpine meadows. Comparison of the alpine Klebsormidium assemblage with data from other biogeographic regions indicated similarity with soil crusts/biofilms from terrestrial habitats in mixed forest in Western Europe, North America, and Asia, as well as walls of buildings in Western European cities. The alpine assemblage differed substantially from crusts from granite outcrops and sand dunes in Eastern Europe (Ukraine), and fundamentally from soil crusts in South African drylands. Epitypification of the known species K. flaccidum, K. crenulatum, K. subtile, K. nitens, K. dissectum, K. fluitans, K. mucosum, and K. elegans is proposed to establish taxonomic names and type material as an aid for practical studies on these algae, as well as for unambiguous identification of alpine strains. New combination Klebsormidium subtile (Kützing) Mikhailyuk, Glaser, Holzinger et Karsten comb. nov. is made.  相似文献   

14.
Autumn migrants preferred to settle on the dorsal leaf surface of peach with gynoparae being more numerous than alate males. These return migrants on peach were similar to those described by others except for a comparatively smaller processus terminalis. Among the oviparae with metatibial pseudosensoria. most (62.5%) had six antennal subdivisions; 25% possessed five antennal subdivisions and half of these were parasitised. Oviparae were bigger than those previously described on plum/damson but their processus terminalis was comparatively shorter. Ultimate instar nymphs were without pseudosensoria and had 5–seg-mented antennae, the VI segment being cleaved from the meriston during the final moult. Alate males mated with the oviparae, mating duration being 3 to 6 min. Oviparae contained, at the most, two well developed eggs at one time, and normally deposited eggs singly during November-December. Most eggs hatched within 20–28 days but those laid in December during colder weather took up to 50 days to hatch. By midJanuary most eggs had hatched. Fundatrix developmental rate was dependent on sap-flow. Overwintering occurred as the fundatrix.  相似文献   

15.
Length–weight relationships (LWRs) were estimated for eight native fish species collected in the lower reaches of the Pearl River, Guangdong Province, South China. Fish were sampled in March and September 2014 and January 2015, using gillnets with various mesh sizes (5–8 cm) and trawl nets with a 3 cm mesh size. A total of 568 specimens of the eight species were analyzed. The r2 values for these species ranged from 0.951 to 0.991. The b values ranged from 3.00 for Takifugu ocellatus and Moolgarda cunnesius, to 3.57 for Clupanodon thrissa. New maximum total lengths are recorded for Takifugu ocellatus (17.6 cm) and Liza carinata (24.4 cm). For five species (Clupanodon thrissa, Megalobrama terminalis, Collichthys lucidus, Coilia grayii, Takifugu ocellatus), the LWRs are presented to fishbase for the first time.  相似文献   

16.
The Insect Growth Regulators with juvenile hormone activity, fenoxycarb and epofenonane, were applied either to separate apple trees, which were artificially inoculated with Adoxophyes orana (F.v.R.) and Pandemis heparana (Denn. & Schiff.), or in apple orchards infested with several naturally occurring leafroller species. The susceptibility of leafrollers to fenoxycarb was very high and the foliar residue remained active for at least 4 weeks. The leafroller parasites Apanteles ater (Ratzeburg) and Colpoclypeus florus (Walker), during their development in or on the host, appeared to be less susceptible to both epofenonane and fenoxycarb than the host itself.
Résumé Le fénoxycarbe et l'épofénonane (régulateurs de croissance des insectes) ont été appliqués soit sur des pommiers isolés, artificiellement inoculés avec Adoxophyes orana (F.v.R.) et avec Pandemis heparana (Denn und Schiff), soit dans des vergers, contaminés naturellement par plusieurs espèces de tordeuses. Sur les arbres isolés, le fénoxycarbe appliqué à raison de 5 g de composé actif/100 l et l'épofénonane de 5 ml de composé actif/100 l, affectent la morphogenèse d'A. orana et P. heparana. Le fénoxycarbe agit sur A. orana même à une concentration de 0,5 g de composé actif/100 l. Dans les vergers, la vaporisation d'épofénonane (750 ml de composé actif/100 l) et de fénoxycarbe (75–150 g de composé actif/100 l) a déformé sévèrement les larves d'A. orana, d'Archips podana (Sc.), de Spilonota ocellana (F.) de P. heparana et d'Archips rosana (L.). Les résidus foliaires actifs ont persisté au moins 4 semaines, comme l'ont montré les effets morphogénétiques observés chez A. orana et P. haparana. Au cours de leur développement, sur ou à l'intérieur de l'hôte, les parasites de tordeuses Apanteles ater (Ratzeburg) et Colpoclypeus florus (Walker), sont moins sensibles à l'épofénonane et au fénoxycarbe que l'hôte lui-même. Des expériences ultérieures à plus grande échelle sont nécessaires pour évaluer l'utilisation des régulateurs de croissance des insectes contre les tordeuses dans le contrôle intégré des vergers.
  相似文献   

17.
A 10‐week feeding trial was conducted to determine the dietary protein requirement of juvenile triangular bream (Megalobrama terminalis). Five semi‐purified diets (white fishmeal as a protein source) were formulated with five crude protein (CP) levels (26.30%, 32.94%, 38.33%, 44.18% and 50.09%; diets P1–P5). Each diet was fed to triplicate groups (20 per fish replicate, initially weighing 1.30 ± 0.02 g). The following parameters were measured to evaluate the effects of different CP levels: weight gain (WG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), daily feed intake (DFI), viscerosomatic index (VSI), hepatosomatic index (HSI), intraperitoneal fat ratio (IPF), lipid retention (LR), liver glycogen content and plasma triglyceride level. The results of the feeding trial showed that WG, SGR and FE were significantly enhanced by an increasing dietary protein level of up to 44.18%, but there were no significant differences in protein levels from 44.18% to 50.09%. The PER and DFI showed a decreasing trend with increasing dietary CP levels. The VSI and HSI were not significantly affected by the different treatments, whereas the IPF increased significantly with decreasing CP levels. The highest LR value, liver glycogen value and triglyceride level in plasma were observed in fish fed the lowest CP diet (P1). Based on the WG and FE, this study suggests an optimum dietary protein level for M. terminalis of 44.18%.  相似文献   

18.
The growth rate of germlings of threeFucus species (F. distichus subsp.edentatus from Iceland,F. vesiculosus from Helgoland, North Sea, andF. virsoides from the North Adriatic Sea) has been investigated under different temperature and salinity conditions. The highest growth rate and the maximum elongation factor were found at 9° C forF. distichus; in the other two species growth increased with increasing temperature. Growth decreases with dilution in the three species under consideration. A rather low tolerance to dilution was observed inF. vesiculosus germlings. In view of the overall distribution of the latter species the opposite was expected. It seems likely, however, that susceptible strains have developed at Helgoland, where salinity rarely drops below 30.  相似文献   

19.
Quantitative determination of antimicrobial compounds produced by the Lactobacillus strains under test was carried out. L. plantarum F1 produced the highest quantity of lactic acid (16.4 g/l) while the lowest amount (0.3 g/l) was produced by L. jensenii F9. All the test organisms produced hydrogen peroxide, with L. brevis OG1 having the highest yield of 0.037 g/l. Diacetyl was also produced by all the organisms, with L. plantarum F1 and L. brevis OG1 having the highest yield of 1.7 g/l, while the lowest producer was L. jensenii F9 (0.86 g/l). Determination of bacteriocin activity was carried out. L. plantarum F1 exhibited 6400 AU/ml bacteriocin activity, while L. brevis OG1 had the lowest activity of 3200 AU/ml using E. coli NCTC10418 as indicator organism. However, L. fermentum F5 and L. jensenii F9 did not produce any detectable bacteriocin. The pH value in the culture supernatant of L. plantarum F1 reached 3.1 within 48 h of incubation, while that of L. jensenii F9 was 5.2. Fufu was prepared using both bacteriocin-producing (BP) L. plantarum F1 and L. brevis OG1, and non-bacteriocin producing L. fermentum F5 and L. jensenii F9. No viable cells of Salmonella typhimurium ATCC13311 and Shigella flexneri AP23498 were detected after 12 h in the cassava products fermented with mixed starter culture of L. plantarum F1 and L. brevis OG1. The rate of survival of enteropathogens in cassava fermented with mixed starter cultures of L. plantarum F1 and L. brevis OG1 was much lower when compared to cassava fermented with mixed starter culture of L. fermentum F5 and L. jensenii F9. At 12 h, the viable count of E. coli NCTC10418 in cassava fermented with mixed starter cultures of L. plantarum F1 and L. brevis OG1 was 1.1 log10 c.f.u./g whereas in cassava fermented with mixed starter cultures of L. fermentum F5 and L. jensenii F9, 8.5 log10 c.f.u./g was obtained The study revealed that fufu produced with BP mixed starter cultures had a better shelf life and kept for 13 days before spoilage occurred, relative to 5 days observed for fufu produced using non-bacteriocin-producing starter cultures, and 6 days for the traditional fermented fufu.  相似文献   

20.
Ganassi  S.  Moretti  A.  Stornelli  C.  Fratello  B.  Bonvicini Pagliai  A.M.  Logrieco  A.  Sabatini  M.A. 《Mycopathologia》2001,151(3):131-138
Fungal strains belonging to the genera Fusarium Paecilomyces and Trichoderma were tested in vitro in order to study their effects against Schizaphis graminum one of the major pests of cereal crops around the world. Biological assays were performed using a solid formulation that was obtained from fungal cultures grown on rice and then finely ground (0.2 mm). The occurrence of toxic secondary metabolites (fumonisin B1 and beauvericin) produced by these fungi was also investigated. In each experiment, three groups of aphids: 15-hour old larvae, 5-day old nymphs with wing buds and wingless morphs were treated with a suspension of a fungal formulation. Some strains belonging to the genera Fusarium and Trichoderma significantly controlled the specimens of the three groups of S. graminum. The F. proliferatum strain ITEM 1407, producing a high level of fumonisin B1 in the culture (1250 g/g), and F. larvarum strain ITEM 2139 had high insecticidal activity (>60%) within 10 minutes after application. As F. larvarum ITEM 2139 did not produce metabolites toxic to mammals, it might be a good candidate as a biocontrol agent of S. graminum in the field.This revised version was published online in October 2005 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