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41.
F.?Mansour H.?AzaizehEmail author B.?Saad Y.?Tadmor F.?Abo-Moch O.?Said 《Phytoparasitica》2004,32(1):66-72
Twenty-nine plant extracts of local species were evaluated for their potential as a source of bioactive ingredients with significant
acaricidal activity that could lead to the development of new and safe bio-acaricides. The crude extracts (70% ethanol) of
these plants were tested for their acaricidal activity against the carmine spider miteTetranychus cinnabarinus in a bioassay under controlled conditions. Mortality, repellency, and the number of eggs laid were measured. Extracts fromEucalyptus camaldulensis andInula viscosa caused more than 25% mortality. Sixteen plant extracts showed significant repellency compared with the control. The six best
extracts, resulting in more than 75% repellency, were fromAllium sativum, Capparis spinosa, Cupressus sempervirens, Lupinus pilosus, Rhus coriaria andTamarix aphylla. Extracts from 16 plants were found to cause a significant reduction in the number of eggs laid compared with the control.
The greatest reduction was achieved by extracts fromC. spinosa, Cyperus rotundus, E. camaldulensis, L. pilosus, Punica granatum, R. coriaria andT. aphylla. A relatively negative fit was found between the mean number of repelled mites and the number of eggs laid (r=−0.65), which
might indicate that most repelled mites were unable to lay eggs before leaving the leaf discs of the bioassay. Our results
show that several plant extracts have good potential for acaricidal activity and are worth further investigation.
http://www.phytoparasitica.org posting Dec. 16, 2003. 相似文献
42.
Said M.S. Massomo Hanne Nielsen Robert B. Mabagala Keld Mansfeld-Giese John Hockenhull Carmen N. Mortensen 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(8):775-789
Black rot, caused by Xanthomonas campestris pv. campestris (Xcc), is a major disease constraint to cabbage production by smallholder farmers in Africa. Variability exists within the pathogen, and yet differentiation of Xcc strains from other closely-related xanthomonads attacking crucifers is often difficult. The Biolog system, fatty acid methyl ester analysis using microbial identification system (MIS), rep-PCR and pathogenicity tests were used to identify and characterise Xcc strains from Tanzania. Great diversity was observed among Xcc strains in their Biolog and rep-PCR profiles. Specific rep-PCR genomic fingerprints were linked to some geographical areas in the country. Most of the Xcc strains were clustered in two groups based on their fatty acid profiles and symptom expression in cabbage although some deviant strains were found. Each of the methods allowed a degree of identification from species, pathovar to the strain level. Biolog and MIS identified all Xcc strains at least to the genus level. Additionally, Biolog identified 47% of Xcc strains to the pathovar and 43% to strain level, whereas MIS identified 43% of the strains to pathovar level. In the absence of a database, the utility of rep-PCR for routine diagnosis of strains was limited, although the procedure was good for delineation of Xcc to the strain level. These findings indicate the existence of Xcc strains in Tanzania that are distinct from those included in Biolog and MIS databases. The limitations noticed warrant continued improvement of databases and inclusion of pathogenicity testing, using universally susceptible cultivars, as an integral part of strain identification. 相似文献
43.
不同温度和pH对恩诺沙星及其代谢产物环丙沙星在渔业下层水体中消除规律的影响 总被引:1,自引:1,他引:0
抗生素进入水体易堆积在水体下层或者底泥中,对水生生物造成不良影响,因此本实验旨在探究恩诺沙星在渔业下层水体中的消除规律,以及代谢产物环丙沙星的生成情况。实验选取了渔业水环境中常见的环境因素(温度和pH),利用液相色谱-串联质谱法,通过正交实验研究这两个环境因素对恩诺沙星(ENR)在水体中降解的影响,同时检测其代谢产物环丙沙星(CIP)的生成及变化情况。实验结果表明,9个处理组中ENR的半衰期变化范围为13~32天,消除率范围为44%~80%。根方差分析可知,pH变化对恩诺沙星的降解有显著影响,而温度变化对其影响不显著,在温度为25℃和pH 5的条件下,恩诺沙星的消除率最高。此外,在实验过程中检测到环丙沙星的产生,其在实验开始的第7天,在pH 5和温度为25℃的条件下浓度达到最高(10.8 ng/mL),之后逐渐降低,在第26天时浓度降低到0~0.16 ng/mL之间。本研究明确了环境因素对恩诺沙星降解的影响,为减少养殖环境中残留的恩诺沙星提供一定的理论指导。 相似文献
44.
45.
Hager Blel Noureddine Chatti Raouf Besbes Sarra Farjallah Ali Elouaer Hammadi Guerbej & Khaled Said 《Aquaculture Research》2008,39(3):268-275
The Mugilidae family is an important fish group representing a major source for fisheries and aquaculture. In the south Mediterranean bank, no data are available on this fauna, except for some morphological studies on Tunisian samples. In this study, 16 allozymic loci were used to investigate the phylogenetic relationships within Tunisian mugilids. The results obtained from Hergla lagoon samples highlight five operational taxonomic unit corresponding to the well‐known species (Liza aurata, Liza ramada, Liza saliens, Chelon labrosus, Mugil cephalus). Several loci appeared to be diagnostic of these species, but in contrast to Greek mugilid samples, we did not find any diagnostic locus fixed differently for the five species. These results can help aquaculture units to identify accurately the mullet species they subsequently use for stocking aquaculture ponds and inland waters. However, species identity represents very important information, as each species has a different growth rate and salinity tolerance. On the other hand, when compared with North Mediterranean Mugilidae analysed until now, Tunisian samples show a genetic differentiation that could be related to different physicochemical conditions between the North and South banks, similar to those recorded in the eastern and western two Mediterranean basins separated by the Siculo‐Tunisian strait. In addition, this study confirms the morphological taxonomy, except for the subdivision of the Liza genus into two sub‐genera. The phylogenetic tree is in agreement with that on Languedoc Mugilidae samples (France), indicating that the subdivision of the Liza genus into two sub‐genera appears to be without any genetic base. 相似文献
46.
Najla Dhen Imen Ben Ammar Chokri Bayoudh Bouthaina Al Mohandes Dridi 《Communications in Soil Science and Plant Analysis》2019,50(8):959-973
Quality of vegetable seedlings is affected by nursery management practices, essentially growing media. For sustainable greenhouse horticulture, it is important to characterize biologically based approaches to improve plantlet quality. Here, we investigate the possibility of developing a biotized growth substrate for nursery production using date palm wastes (DPWs) peat as an alternative to commercial sphagnum peat and indigenous arbuscular mycorrhizal fungi (AMF). A greenhouse experiment was established using different rates of DPWs peat to substitute commercial peat in both conventional and organic nursery production systems. Lettuce seedlings were inoculated or not with native AMF isolated from plots with conventional or organic production system (CM and OM respectively). When lettuce plantlets attained commercial size, a microscopic observation revealed that the establishment of mycorrhizal association was successful in all mixtures of growing media. Significant increase in growth parameters (height shoot, number and area of leaves, shoot and root biomass) were observed on plantlets inoculated with indigenous AMF isolated from organic plot compared to those isolated from conventional plot and to control (without AMF). Commercial peat partial substitution with DPWs peat in proportion of 25–50% improves better lettuce performance than complete-peat use. Consequently, these mixtures seem to be an appropriate formulation for sustainable nursery production. 相似文献
47.
Brita?Dahl?JensenEmail author Said?M.?S.?Massomo Ignas?S.?Swai John ?Hockenhull Sven?Bode?Andersen 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(3):297-308
Black rot, caused by Xanthomonas campestris pv. campestris, (Xcc), is one of the most serious diseases of crucifers world-wide. Forty-nine genotypes were evaluated for resistance under field
conditions in Tanzania after artificial inoculation with Xcc race 1. Open pollinated white cabbage cultivars were generally susceptible, while Portuguese and pointed cabbages exhibited
partial resistance. Some F1 white cabbage cultivars were highly susceptible, whereas others exhibited a high level of partial
resistance. The most promising of the hybrid cultivars were T-689 F1, Gianty F1, No. 9690 F1, N 66 F1, and SWR-02 F1. Breeding
line Badger I-16 exhibited the highest level of resistance of all genotypes. The genotypes accounted for 72.9–75.5% of the
variation of the disease severity when assessed on the leaves, and 71.4% of the variation when assessed as internal black
rot in heads at harvest. High correlations (equal to or above 0.7) were found between disease severities assessed on leaves
three times during the growing season and also with the amount of internal black rot in heads. Leaf loss also was correlated
with disease severity. The high genetic determination of the trait and the high correlations between disease assessments indicate
that selection for resistance to black rot will be efficient when field screenings are carried out. Evaluation of genotypes
for disease severity on leaves during the growing season combined with evaluations of head resistance in the most promising
genotypes may be a simple method to select resistant cultivars. 相似文献
48.
49.
ABSTRACT The cellular protein Hv-p68 is a novel alcohol oxidase/RNA-binding protein that is overexpressed in virus-infected isolates of the plant-pathogenic fungus Helminthosporium victoriae (teleomorph: Cochliobolus victoriae). Overproduction of Hv-p68 has been hypothesized to lead to the accumulation of toxic aldehydes and to induce the disease phenotype associated with the virus-infected isolates. We overexpressed the Hv-p68 gene in virus-free isolates and evaluated the morphology of the resulting colonies. We cloned and sequenced the Hv-p68 genomic DNA, which contains five introns and the complete Hv-p68 coding sequence. Vectors for overexpression of the Hv-p68 gene were constructed with either Hv-p68 cDNA or the intron-containing Hv-p68 genomic DNA. Expression of Hv-p68 was significantly higher if the genomic sequence was used for transformation than if the cDNA sequence was used. The virus-free fungal transformants that overexpressed Hv-p68 gene did not exhibit the disease phenotype. In contrast, these transformants showed enhanced growth rates when compared with the nontransformed and empty vector controls. Interestingly, overexpression of Hv-p68 in a fungal isolate infected with both the totivirus Helminthosporium victoriae 190S virus (Hv190SV) and the chrysovirus Helminthosporium victoriae 145S virus (Hv145S) showed enhanced accumulation of the Hv145SV double-stranded (ds)RNA, but not of the Hv190SV. These results are consistent with an earlier report that Hv-p68 co-purified with viral dsRNA, mainly that of the Hv145SV. Elucidation of the role of Hv-p68 in disease induction is important for an understanding of host-virus interactions in this fungus-virus system. 相似文献
50.
Physiological and Yield Responses of Faba bean (Vicia faba L.) to Drought Stress in Managed and Open Field Environments
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M. H. Ammar F. Anwar E. H. El‐Harty H. M. Migdadi S. M. Abdel‐Khalik S. A. Al‐Faifi M. Farooq S. S. Alghamdi 《Journal of Agronomy and Crop Science》2015,201(4):280-287
Water scarcity is threatening the sustainability of global food grain production systems. Devising management strategies and identification of crop species and genotypes are direly required to meet the global food demands with limited supply. This study, consisted of two independent experiments, was conducted to compare faba bean (Vicia faba L.) genotypes Giza Blanka, Goff‐1, Hassawi‐1, Hassawi‐2 and Gazira‐2 in terms of physiological attributes and yield under water‐limited environments. In first experiment, conducted in a growth chamber, osmotic stress of ?0.78, ?0.96, ?1.19 and ?1.65 MPa was induced using polyethylene glycol for 4 weeks. In second experiment, conducted in open field for two consecutive growing seasons, water deficit treatments were applied 3 weeks after sowing. In this experiment, irrigation was applied when an amount of evaporated water from the ‘class A pan’ evaporation reached 50 mm (well watered), 100 mm (moderate drought) and 150 mm (severe drought). Water deficit, applied in terms of osmotic stress or drought, reduced the root and shoot length, related leaf water contents, total chlorophyll contents and efficiency of photosystem‐II, plant height, grain yield and related attributes in faba bean; increased the leaf free proline, leaf soluble proteins and malondialdehyde contents, and triggered the maturity in tested faba bean genotypes. However, substantial genetic variation was observed in the tested genotypes in this regard. For instance, root length of genotypes Giza Blanka and Hassawi‐2 decreased gradually, whereas it was increased in genotypes Goff‐1, Hassawi‐1 and Gazira‐2 with increase in the level of osmotic stress. Genotypes Gazira‐2 and Hassawi‐2 had better relative leaf water contents, leaf free proline and soluble proteins under water deficit conditions; however, these were minimum in genotype Giza Blanka. Better accumulation of leaf free proline, soluble proteins, and maintenance of chlorophyll contents, tissue water, efficiency of photosystem‐II and grain weight in water‐limited conditions helped some genotypes like Hassawi‐2 to yield better. Future breeding programs for developing new faba bean genotypes for water‐limited environments may consider these traits. 相似文献