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1.
Micromorphological investigation of the types, dimensions and distribution of characteristic trichomes in leaves and stems in Teucrium L. species (T. arduini L., T. chamaedrys L., T. flavum L., T. montanum L., T. polium L., and T. scordium L. subsp. scordioides Schreb.) distributed in Croatia was carried out as part of the taxonomical study of the genus Teucrium. Secretory types of hairs, peltate and capitate hairs were observed on the epidermis of stems and leaves of all investigated species. Non-secretory, acicular hairs were almost completely lacking on stems of T. scordium subsp. scordioides. Flagelliform hairs were not found in T. flavum and T. polium. Cladose hairs were present only in T. polium. The largest micromorphological variability was established between wild and cultivated samples of T. arduini and T. scordium subsp. scordioides, while cultivated and wild specimens of T. polium were almost identical. Differences were primarily observed in trichome dimensions and much less in micromorphological features.  相似文献   

2.
BOOK REVIEWS     
Book reviews in this article: Ahmadjian, V. & Paracer, S. 1986. Symbiosis. An Introduction to Biological Associations. Stephen, L. E. 1986. Trypanosomiasis: A Veterinary Perspective. Smith, D. C. & Douglas, A. E. 1987. The Biology of Symbiosis. Gyles, D. L. & Thoen, C. O. , eds. (with 22 contributors). 1986. Pathogenesis of Bacterial Infections in Animals. Fenchel, T. 1987. Ecology of Protozoa: The Biology of Free-living Phagotrophic Protists. Maeda, M. & Carey, P. G. 1986. An Illustrated Guide to Oligotrichine Ciliates.  相似文献   

3.
The caridean shrimp Gnathophylloides mineri lives among the spines of various species of sea urchins. The shrimp has cryptic coloration that closely matches the coloration of the Caribbean urchin Tripneustes ventricosus. Despite this camouflage, in Jamaica, G. mineri is three times more abundant on the urchin Lytechinus variegatus than on T. ventricosus. L. variegatus exhibits more pronounced covering behavior than T. ventricosus. In laboratory choice experiments, the shrimp exhibited no preference between live, uncovered T. ventricosus or L. variegatus. Similarly, there was no preference between models (the tests, with spines attached, of hollowed out urchins) of T. ventricosus or L. variegatus without cover, or between models of T. ventricosus or L. variegatus with switched cover (i.e., each model was covered with the debris that had belonged to its partner when collected). There was, however, a significant preference for L. variegatus models with their natural covering over T. ventricosus with their natural covering. The shrimp may prefer L. variegatus with its extensive covering over T. ventricosus with extensive covering because the spines of the former are typically erect, as opposed to the spines of T. ventricosus, which usually lay flat across the test and would not give the shrimp much room to maneuver under the debris layer. Our study indicates that despite effective morphological and behavioral traits that render an organism highly cryptic, other, more effective, means of concealment may undermine the usefulness of this crypsis.  相似文献   

4.
Honeydew-excreting hemipterans, such as mealybug pests, can be protected from their natural enemies by tending ants in return for honeydew, thereby compromising the aims of biological control. In this respect, antagonistic interactions between the ant Tapinoma nigerrimum, native to the Mediterranean basin, and the main natural enemies of both the vine mealybug (VMB), Planococcus ficus, and the citrus mealybug (CM), Planococcus citri, were assessed in laboratory conditions. Parasitism of vine and CMs by their respective parasitoids, Anagyrus sp. nr. pseudococci and Leptomastix dactylopii, was negatively affected by the ant T. nigerrimum. Similarly, T. nigerrimum was shown to significantly disrupt the predatory potential of ladybird larvae, Cryptolaemus montrouzieri, when foraging on host CMs. By contrast, the presence of the ant did not negatively influence the predatory activity of C. montrouzieri adults when feeding on CMs. Consequently, the encyrtid parasitoids A. sp. nr. pseudococci and L. dactylopii and the larval stage of the predator C. montrouzieri may be considered as T. nigerrimum-sensitive, whereas the adults of C. montrouzieri may be regarded as T. nigerrimum-resistant predators. Accordingly, the ant T. nigerrimum constitutes a threat to the biological control of mealybugs by either the encyrtids A. sp. nr. pseudococci and L. dactylopii or the larval stage of the ladybird C. montrouzieri. Hence, adequate control of T. nigerrimum is highly recommended before any release of these mealybugs' natural enemies.  相似文献   

5.
The glutenin and gliadin proteins of wild emmer wheat, Triticum turgidum L. var. dicoccoides, have potential for improvement of durum wheat (T. turgidum L. var. durum) quality. The objective of this study was to determine the chromosomes controlling the high molecular weight (HMW) glutenin subunits and gliadin proteins present in three T. turgidum var. dicoccoides accessions (Israel-A, PI-481521, and PI-478742), which were used as chromosome donors in Langdon durum- T. turgidum var. dicoccoides (LDN-DIC) chromosome substitution lines. The three T. turgidum var. dicoccoides accessions, their respective LDN-DIC substitution lines, and a number of controls with known HMW glutenin subunits were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), urea/SDS-PAGE, and acid polyacrylamide gel electrophoresis (A-PAGE). The results revealed that all three T. turgidum var. dicoccoides accessions possess Glu-A1 alleles that are the same as or similar to those reported previously. However, each T. turgidum var. dicoccoides accession had a unique Glu-B1 allele. PI-478742 had an unusual 1Bx subunit, which had mobility slightly slower than the 1Ax subunit in 12% SDS-PAGE gels. The subunits controlled by chromosome 1B of PI-481521 were slightly faster in mobility than the subunits of the Glu-B1n allele, and the 1By subunit was identified as band 8. The 1B subunits of Israel-A had similar mobility to subunits 14 and 16. The new Glu-B1 alleles were designated as Glu-B1be in Israel-A, Glu-B1bf in PI-481521, and Glu-B1bg in PI-478742. Results from A-PAGE revealed that PI-481521, PI-478742, and Israel-A had eight, 12, and nine unique gliadin bands, respectively, that were assigned to specific chromosomes. The identified glutenin subunits and gliadin proteins in the LDN-DIC substitution lines provide the basis for evaluating their effects on end-use quality, and they are also useful biochemical markers for identifying specific chromosomes or chromosome segments of T. turgidum var. dicoccoides.Communicated by B. Friebe  相似文献   

6.
Thellungiella halophila is a salt‐tolerant close relative of Arabidopsis thaliana. Significant mRNA similarity was confirmed by hybridization of T. halophila mRNA with the A. thaliana GeneChip ATH1. To establish a platform for future molecular comparison of the two species several physiological mechanisms, which may confer high salt tolerance to T. halophila, were investigated. Determination of ion content in shoots and roots of A. thaliana and T. halophila indicated different strategies of ion uptake and translocation from root to shoot in the two species. During salt stress T. halophila accumulated less sodium than A. thaliana. Tissue concentrations of sodium and potassium showed negative correlation in A. thaliana but not in T. halophila. Electrophysiological experiments proved high potassium/sodium selectivity of root plasma membrane channels in T. halophila. In particular, voltage‐independent currents were more selective for potassium in T. halophila than in A. thaliana. Single cell sampling of T. halophila leaves during salt exposure revealed increased concentrations of sodium and decreased concentrations of potassium in epidermal cells suggesting that this cell type could function to ensure storage of sodium and exchange of potassium with the rest of leaf. Application of salt resulted in a sharp drop of transpiration in A. thaliana. By contrast, transpiration in T. halophila responded more slowly and was only slightly inhibited by salt treatment, thus maintaining high water uptake and ion transport.  相似文献   

7.
The brown citrus aphid, Toxoptera citricida (Kirkaldy), is a serious pest of citrus because it efficiently transmits citrus tristeza closterovirus (CTV). The invasion of Jamaica's citrus by T. citricida resulted in serious economic losses and the importation and consideration was given to the establishment of Lipolexis oregmae Gahan (Hymenoptera: Aphidiidae) in a classical biological control program. Prior to introducing L. oregmae, we conducted a survey to determine the abundance of Lysiphlebus testaceipes Cresson (Hymenoptera: Aphidiidae) in T. citricida. A high-fidelity PCR analysis was conducted using Lysiphlebus- and Lipolexis-specific ITS2 rRNA primers on alcohol-preserved brown citrus aphids and the results were positive for both parasitoids. The fortuitous establishment of L. oregmae in Jamaica was surprising, and was confirmed by rearing adults from parasitized aphids and obtaining taxonomic confirmation based on morphology. In addition, its identity was confirmed molecularly by cloning and sequencing 16S, 12S, and COI sequences from the Florida colony of L. oregmae and from Jamaican specimens. The three DNA sequences were 100% identical for specimens from both sources. The phylogenetic analysis using 16S sequences indicated a close relationship of the Florida and Jamaica populations of L. oregmae with L. gracilis. During 2005, an island-wide survey of citrus in six parishes confirmed that both L. testaceipes and L. oregmae commonly parasitize T. citricida, but that L. oregmae was the more widely distributed and abundant parasitoid. The pathway by which L. oregmae might have entered Jamaica is discussed.  相似文献   

8.
Leuconostoc mesenteroides subsp. dextranicum strain J24 synthesized a bacteriocin named Dextranicin 24 (Dex-24), which inhibited only other Leuconostoc sp. strains. It was purified by a two-step procedure from the fraction of the bacteriocin bound to the producer cells at the end of the growth: desorption form the cells at acidic pH, followed by reserve phase HPLC. The N-terminal sequence of Dex-24 was the following: NH2− K G V L G W L S M A S S A L T G P Q Q . . . Received: 26 January 1996 / Accepted: 28 March 1996  相似文献   

9.
The growth strategy of an emergent plant, Typha orientalis Presl, was examined in experimental ponds in comparison with two other Typha species distributed in Japan, Typha latifolia L. and Typha angustifolia L. T. orientalis showed the greatest ability of vegetative reproduction at the expense of growth in height. T. orientalis started to produce new ramets earlier than T. latifolia and T. angustifolia. These results suggest that T. orientalis should be a rather pioneer-like species and would be restricted to disturbed habitats.  相似文献   

10.
11.

The effect of Lactococcus lactis subsp. lactis strain PTCC 1403 as a potential probiotic was investigated on the growth, hematobiochemical, immune responses, and resistance to Yersinia ruckeri infection in rainbow trout. A total of 240 fish were distributed into 12 fiberglass tanks representing four groups (× 3 replicates). Each tank was stocked with 20 fish (average initial weight: 11.81 ± 0.32 g) and fed L. lactis subsp. lactis PTCC 1403 at 0 (control, T0), 1 × 109 (T1), 2 × 109 (T2), and 3 × 109 (T3) CFU/g feed for 8 weeks. The results showed enhanced protein efficiency ratio and reduced feed conversion ratio in the fish-fed T2 diet. Further, fish-fed T2 and T3 diets showed a significantly higher survival rate than the control (p < 0.05). Trypsin, lipase, and protease activities were increased in fish-fed L. lactis subsp. lactis PTCC 1403 compared to the control (p < 0.05). Fish fed with a T2 diet showed significantly (p < 0.05) lower glucose content than other groups. The blood lysozyme activity and IgM showed significantly (p < 0.05) higher values in fish-fed T2 and T3 diets than in other groups. The antioxidative responses were increased in fish-fed T2 and T3 diets (p < 0.05). After 7 days post-Y. ruckeri challenge, the cumulative mortality rate showed the lowest value in fish fed with T1 and T2 diets, while the highest value was recorded in the control group. In conclusion, the results revealed beneficial effects of L. lactis subsp. lactis PTCC 1403 on the feed efficiency, immune response, and resistance to Y. ruckeri infection in rainbow trout.

  相似文献   

12.
Lactobacillus plantarum can exert additional probiotic effects via regulation of human immune system. However, the direct interaction between probiotics and the receptors of immune cells still needs to be further studied. To identify the receptor of dendritic cells during the interaction with L. plantarum. Dendritic cells were pretreated with L. plantarum and the antibody to dendritic cells specific intercellular adhesion molecule-grabbing nonintegrin (DC-SIGN), toll like receptor (TLR)-2 and TLR-4. The maturation of immature dendritic cells, cytokine production, and modulation of T cells were studied by flow cytometry. Adherence between L. plantarum and dendritic cells were studied by ELISA, flow cytometry, and Western blot. L. plantarum could mature dendritic cells by up-regulating MHC-II and CD80 and CD86. Anti-inflammatory interlectin (IL)-10 and IL-6 was up-regulated and pro-inflammatory IL-12p70 was retro-regulated by L. plantarum. L. plantarum may interact with DC-SIGN and modulate of T to differentiate into IL-4 producing T cells. The interaction of L. plantarum and DC-SIGN and the biological effects could be blocked by EDTA and antibody to DC-SIGN. Effects of L. plantarum were concentration-dependent. L. plantarum could bind to DC-SIGN to improve DC maturation at different ratios, regulate the secretion of anti-inflammatory and pro-inflammatory cytokines, and induce the polarization of interlectin-4-producing T cells.  相似文献   

13.
  • 1 The carrot psyllid Trioza apicalis and Lygus rugulipennis can cause serious damage to cultivated carrots, especially at the seedling stage. The essential oil composition in leaves of several carrot varieties was studied in relation to oviposition acceptance by sucking insect herbivores that have different feeding strategies. Of the insect species studied, T. apicalis is a carrot specialist, T. anthrisci is an Apiaceae specialist, and L. rugulipennis is a generalist.
  • 2 The oil composition differed significantly between leaves from different carrot varieties (Flakkeer 2, Nantura, Parano, Napoli, Panther, Splendid, Nantes 3 Express).
  • 3 There were no differences in the mean numbers of eggs laid by T. apicalis or T. anthrisci on different varieties, but L. rugulipennis laid fewer eggs on the Panther variety than on Nantes 3 Express.
  • 4 There was a negative linear correlation between limonene concentration and number of eggs laid by T. apicalis, confirming that limonene is a repellent to the carrot psyllid. Results suggest that only particular compounds influence the preference of the carrot psyllid, and these compounds may not be the main components in the essential oil of carrots.
  • 5 A positive correlation was found between myrcene concentration and number of eggs laid by T. anthrisci. Essential oil composition did not explain egg‐laying preference of L. rugulipennis.
  • 6 The results indicate that essential oil composition of carrot varieties affects host preference of Apiaceae specialists more than that of generalists.
  相似文献   

14.
The life history and host-specificity of the flea beetle,Altica cyanea (Weber) [Coleoptera: Chrysomelidae], were studied to determine its potential value as a biological control agent for water primrose,Ludwigia adscendens (Onagraceae). Females laid a mean of 146 yellowish eggs in masses on this weed and larvae passed through 3 instars. This multivoltine insect completed a generation in 80–84 days. In preliminary host-specificity trials, larvae and adults fed slightly on 2 varieties ofTrapanatans, but they caused considerable damage toLudwigia spp.; no feeding occurred on rice. In host plant choice tests, larvae and adults preferred to feed onL. adscendens andL. prostata toT. natans. In these same tests, onlyLudwigia spp. supported complete development, but it was fastest onL. adscendens. Adults that were reared onL. adscendens lived longer and laid more eggs than those reared onL. prostata, suggesting thatA. cyanea may be a promising biological control agent forL. adscendens growing in rice-paddies. AdultZicrona coerulea L. [Hemiptera: Pentatomidae] preyed upon 3rd instarA. cyanea larvae in the laboratory.   相似文献   

15.
S. J. Bostock 《Oecologia》1978,36(1):113-126
Summary The germination responses of seeds of Achillea millefolium L., Artemisia vulgaris L., Cirsium arvense (L.) Scop., Taraxacum officinale Weber, sensu lato, and Tussilago farfara L. to light, nitrate, alternating temperatures, chilling, light quality, and water availability were studied in laboratory tests, using fresh seed and seed stored for 6 months at 27°C and buried in the soil. A factorial experiment with light, nitrate, alternating temperatures, and seed age as factors found that all four affected germination except in T. farfara. All three external factors were stimulatory, especially in combinations. Fresh seed of A. vulgaris and C. arvense showed a light x alternating temperature synergism, responded to chilling, and after-ripened in cold dry storage. That of T. farfara had no dormancy and rapid germination, and germinated well on substrates with a water content too low for the other species. Seed of A. millefolium and A. vulgaris had good survival in both experimental storage conditions, while that of C. arvense and T. officinale did not, and that of T. farfara did not survive. Longevity in both conditions was associated with depth of initial dormancy. The two conditions caused different changes in dormancy in both A. vulgaris and A. millefolium. The germination behaviour, and the size, morphology and dispersal of the seeds of the species are discussed as strategies adapted to intermittently available situations for seedling establishment.  相似文献   

16.
The META cluster of Leishmania amazonensis contains both META1 and META2 genes, which are upregulated in metacyclic promastigotes and encode proteins containing the META domain. Previous studies defined META2 as a 48.0-kDa protein, which is conserved in other Leishmania species and in Trypanosoma brucei. In this work, we demonstrate that META2 protein expression is regulated during the Leishmania life cycle but constitutive in T. brucei. META2 protein is present in the cytoplasm and flagellum of L. amazonensis promastigotes. Leishmania META2-null replacement mutants are more sensitive to oxidative stress and, upon heat shock, assume rounded morphology with shortened flagella. The increased susceptibility of null parasites to heat shock is reversed by extra-chromosomal expression of the META2 gene. Defective Leishmania promastigotes exhibit decreased ability to survive in macrophages. By contrast, META2 expression is decreased by 80% in RNAi-induced T. brucei bloodstream forms with no measurable effect on survival or resistance to heat shock.  相似文献   

17.
A series of laboratory and field studies were done to evaluate a range of leguminous plant species for their feeding potential by adult weevils of the genusSitona Germar. (Coleoptera: Curculionidae). Three species ofSitona, S. lineatus L.,S. flavescens Marsh. andS. hispidulus F. all of which are found commonly on white clover (Trifolium repens L.) in the UK were offered a range of 11 legume species,T. repens (white clover, cv. Olwen),T. pratense L. (red clover, cv. Marcom),T. fragiferum L. (strawberry clover, cv. Palestine),T. hybridum L. (hybrid clover, cv. Tetra),T. incarnatum L (crimson clover),T. dubium Sibth. (lesser yellow trefoil),Lotus corniculatus L. (birdsfoot-trefoil, cv. Leo),L. uliginosus Schkuhr. (large birdsfoot-trefoil),Melilotus alba Desr. (white melilot),Medicago sativa L. (lucerne, cv. Europe) andM. lupulina L. (black medick) in two laboratory experiments. The weevils were offered a choice of these legumes in one experiment whilst in the other they did not have a choice of food material. These legumes were also sown in the field and a number of measurements of damage, together with counts ofSitona spp., were made. In the laboratoryS. lineatus andS. hispidulus favoured some of the legumes to a greater or lesser extent than white clover.S. flavescens was more restricted in its feeding than the other two weevil species. In the field studyS. lineatus invaded the experimental area quickly and tended to favourMedicago spp. andMelilotus spp. Later in the yearS. flavescens dominated the sitona fauna on the experiment, with the exception of aggregations ofS. lineatus onM. sativa andM. alba. In a separate screen of 5 varieties of white clover (cvs Donna, Menna, Kersey, Olwen and Grasslands Huia), cv. Olwen appeared to be the most susceptible to sitona attack.  相似文献   

18.
Ascophyllum nodosum (L.) Le Jol. forms extensive beds in wave‐sheltered, rocky intertidal habitats on the northwestern Atlantic coast. This fucoid seaweed is host to an obligate red algal epiphyte, Vertebrata lanosa (L.) T. A. Chr. [=Polysiphonia lanosa (L.) Tandy], and two facultative brown algal epiphytes, Elachista fucicola (Velley) Aresch. and Pylaiella littoralis (L.) Kjellm. Although V. lanosa can occur throughout most of the length of host fronds, it largely predominates in midfrond segments. The two brown algal epiphytes are restricted to distal segments. Through field experiments conducted in Nova Scotia, Canada, we tested the hypothesis that surface wounds are required for the colonization of distal segments of host fronds by V. lanosa. Distal tissues normally have a smooth surface because of their young age (A. nodosum fronds grow apically). By creating small wounds that mimicked grazing wounds distributed elsewhere on host fronds, we demonstrated that V. lanosa can colonize distal frond segments during the growth and reproductive season (summer and autumn). Approximately half of the artificial wounds were colonized by V. lanosa during this time. The experimental exclusion of both brown algal epiphytes from distal frond segments did not affect colonization by V. lanosa. Thus, we conclude that the absence of surface irregularities on distal segments of host fronds, specifically small wounds, is the main factor explaining the absence of V. lanosa there. We propose that further experimental work clarifying epiphyte distribution in host beds will enhance our ability to understand the functional role of epiphytes in intertidal ecosystems.  相似文献   

19.
The maxicircle control region [also termed divergent region (DR)] composed of various repeat elements remains the most poorly studied part of the kinetoplast genome. Only three extensive DR sequences demonstrating no significant similarity were available for trypanosomatids (Leishmania tarentolae, Crithidia oncopelti, Trypanosoma brucei). Recently, extensive DR sequences have been obtained for Leishmania major and Trypanosoma cruzi. In this work we have sequenced DR fragments of Leishmania turanica, Leishmania mexicana, Leishmania chagasi and two monogenetic trypanosomatids Leptomonas seymouri and Leptomonas collosoma. With the emergence of the additional extensive sequences some conserved features of DR structure become evident. A conserved palindromic sequence has been revealed in the DRs of the studied Leishmania species, L. seymouri, and T. cruzi. The overall DR structure appears to be similar in all the Leishmania species, their relative L. seymouri, and T. brucei: long relatively GC-rich repeats are interspersed with clusters of short AT-rich repeats. C. oncopelti, L. collosoma, and T. cruzi have a completely different DR structure. Identification of conserved sequences and invariable structural features of the DR may further our understanding of the functioning of this important genome fragment.Electronic Supplementary Material Supplementary material is available to authorized users in the online version of this article at Nucleotide sequence data reported in this paper are available in the GenBank™, EMBL and DDBJ databases under the accession numbers DQ107351, DQ107352, DQ107354-DQ107358, DQ239759-DQ239765, DQ492251-DQ492256.  相似文献   

20.
Malformation disease of Mango (Mangifera indica L.) caused by Fusarium moniliforme var. subglutinans is one of the most destructive diseases, which is a major production constraint in the mango-growing regions of India. In this study, The bioagents Trichoderma viride (Tr1), Trichoderma virens (Tr2) and Trichoderma harzianum (Tr3) were evaluated in culture with the pathogens to monitor the antagonistic effect and their volatile compound and culture filtrates (non-volatile compound). It was found that all the three isolates of bioagents significantly checked the growth of F. moniliforme var. subglutinans. In dual culture, the best result was obtained with T. harzianum followed by T. virens and T. viride. A similar result was also observed in the case of culture filtrates ofTrichoderma spp. The results clearly showed that inhibition of the growth of the fusaria isolates by T. harzianum was significantly superior to T. viride andT.virens. In case of antifungal activity of volatile compounds released by Trichoderma isolates, it was also observed that T. virens was more superior to T.harzianum and T. viride.  相似文献   

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