2种昆虫病原真菌对草地贪夜蛾体表侵染模式的扫描电镜观察          下载免费PDF全文

雷妍圆  官昭瑛  Shoaib Freed  Syed Muhammad Zaka  Abid Hussin  章玉苹 《南方农业学报》2021,52(3):578-588

【目的】在前期筛选获得对草地贪夜蛾高效致病真菌球孢白僵菌（Beauveria bassiana）菌株GZSL-1和玫烟色虫草（Cordyceps fumosorosea）菌株IFCF01的基础上,进一步明确2株菌株在草地贪夜蛾体表的侵染模式,为阐明菌株致病机理,提高昆虫病原真菌对草地贪夜蛾的防效提供理论依据。【方法】利用扫描电镜观察草地贪夜蛾2龄幼虫分别接种菌株GZSL-1和IFCF01（孢子悬浮液浓度为1.0×107孢子/mL）后分生孢子在幼虫体表附着、萌发、穿透和增殖的过程。【结果】菌株GZSL-1和IFCF01萌发后均可形成附着胞,草地贪夜蛾幼虫体表结构对2株菌株分生孢子萌发、附着和穿透芽管长度有不同程度的影响。2株菌株在各结构区均有较高的萌发率（> 90.00%）和附着胞率（> 80.00%）,在平缓结构区比瘤状突起结构区观察到更短的穿透芽管。在各结构区,菌株GZSL-1形成的穿透芽管长度均短于菌株IF-CF01相应的芽管长度,在平缓结构区,菌株GZSL-1的穿透芽管长度显著短于菌株IFCF01（P<0.05）。菌株GZSL-1和IFCF01分生孢子接种后分别在16和8 h内萌发,在24和32 h内普遍出现穿透结构穿透草地贪夜蛾幼虫体壁。2株菌株的初级和次级分生孢子分别在接种后72和96 h内出现。【结论】扫描电镜观察证实球孢白僵菌菌株GZSL-1和玫烟色虫草菌株IFCF01对草地贪夜蛾具有高致病性,揭示了病原真菌分生孢子在草地贪夜蛾虫体上的侵染过程,结果为后续2株菌株的改良及田间应用打下理论基础。  相似文献   

Comparison of net ecosystem CO₂ exchange in two peatlands in western Canada with contrasting dominant vegetation, Sphagnum and Carex     

Aaron J. Glenn  Lawrence B. Flanagan  Kamran H. Syed  Peter J. Carlson 《Agricultural and Forest Meteorology》2006,140(1-4):115

Net ecosystem carbon dioxide exchange was measured in two contrasting peatlands in northern Alberta, Canada using the eddy covariance technique during the growing season (May–October). Sphagnum spp. made up approximately 66% of the total LAI (1.52 m² m⁻²) at the poor fen and the total N content of Sphagnum capitula was 7.8 mg g⁻¹ at the peak of the growing season. In contrast, the dominant plant species at the extreme-rich fen site, the perennial sedge, Carex lasiocarpa, accounted for approximately 60% of the total LAI (1.09 m² m⁻²), and had leaf total N content of 19.3 mg g⁻¹ at peak biomass. In addition, the peak aboveground biomass was higher at the poor fen (230.9 g m⁻²) than at the extreme-rich fen (157.1 g m⁻²). Both sites had maximum daily rates of net CO₂ uptake of approximately 5 μmol m⁻² s⁻¹, and typical nighttime rates of CO₂ loss of approximately 2 μmol m⁻² s⁻¹ during the peak of the growing season. Calculations of maximum photosynthetic and respiratory capacity were consistently higher at the extreme-rich fen. The poor fen was a net sink for CO₂ during 4 of the 6 months (peaking at 44 g C m⁻² in July), while only slight net losses of CO₂ (3 g C m⁻²) occurred in May and September. In contrast, the extreme-rich fen was calculated to be a significant net sink for CO₂ only during 2 months of the growing season (peaking at 30 g C m⁻² in August), while significant net losses of CO₂ occurred in May (8 g C m⁻²) and in October (13 g C m⁻²). The plant species at the poor fen site were active earlier and later in the growing season, while it took longer for C. lasiocarpa to develop leaf tissue, and leaf senescence and reduction in photosynthetic activity occurred earlier in the fall at the extreme-rich fen. When integrated over the 6-month growing season, the poor fen was a net sink (90 g C m⁻²) that was three times larger than the extreme-rich fen (31 g C m⁻²). The ratio of cumulative total ecosystem respiration to gross primary production was 0.7 at the poor fen and 0.9 at the extreme-rich fen.  相似文献   

Investigating the effect of Azospirillum brasilense and Rhizobium pisi on agronomic traits of wheat (Triticum aestivum L.)     

Muhammad Saqlain Zaheer  Muhammad Farrukh Saleem  Imran Haider Khan  Salman Ahmad  Rashid Iqbal 《Archives of Agronomy and Soil Science》2013,59(11):1554-1564

ABSTRACT

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T_{0 –} no-inoculation (control), T₁ – Azospirillum brasilense inoculation, T₂ – Rhizobium pisi inoculation and T₃ – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T₃ were about 9% and 14% higher than values for sole inoculations in T₁ and T₂. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat.  相似文献   

The possible role of organic acids as allelochemicals in Tamarindus indica L. leaves     

Sairah Syed  Zammurad Iqbal Ahmed  Muhammad Imran Al-Haq  Ashiq Mohammad  Yoshiharu Fujii 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(6):511-517

Tamarindus indica L. is well known for its acidic nature and allelopathic potential, but to date, little is known about its organic acids playing their role as allelochemicals. Hence, in the present study, identification, quantification, and contribution of organic acids present in its leaf extract were conducted using the principle of bioassay-guided procedure. High pressure liquid chromatography identified four organic acids, viz. citric, malic, oxalic, and tartaric acids, in its leaf aqueous extract with the predominance of oxalic acid (7.5 g kg^?1 leaves fresh weight) followed by tartaric acid (7.3 g kg^?1). The allelopathic activity of identified acids and aqueous extract was evaluated on lettuce seedlings growth based on the specific activity (EC₅₀). The crude extract reduced radicle growth more adversely than hypocotyl at the concentration of 2.5 g L^?1 (EC₅₀). It hindered the normal physiological growth process through weak and curly seedlings, and necrosis of their tips. Among the identified acids, oxalic acid had the highest specific activity (40 mg L^?1) and citric acid had the lowest (>1000 mg L^?1). As a consequence of its high contents, the total activity, a function of specific activity and concentration, of oxalic acid (188) was found higher followed by tartaric acid (146). The contribution of both acids influencing the specific activity of the crude extract was then turned out to be 74%. To the best of our knowledge, this is the first report identifying the oxalic and tartaric acids as growth inhibitors in tamarind leaves and quantifying their contribution in its allelopathic expression. Based on the total activity, the results suggested that oxalic and tartaric acids are the major allelochemicals in tamarind leaves. The allelopathic potential of these acids might promote the development of natural herbicides as an alternative to the synthetic ones in a most sustainable manner.  相似文献   

Immunodetection of coproantigens for the diagnosis of amphistomosis in naturally infected Indian Water Buffalo,Bubalus bubalis     

Mohammad K. Saifullah  Gul Ahmad  Syed M.A. Abidi 《Veterinary parasitology》2013,191(1-2):66-72

The infection of gastrointestinal helminths in livestock is routinely diagnosed by microscopical examination of faecal samples for the presence of ova/eggs but this approach becomes ineffective for the seasonally egg producing trematodes. Therefore, an alternative approach to detect the coproantigens of liver and rumen amphistomes, Gigantocotyle explanatum and Gastrothylax crumenifer respectively, infecting Indian water buffalo Bubalus bubalis, was undertaken using ELISA, immunodot and countercurrent immunoelectrophoresis (CCIEP). The hyperimmune polyclonal antisera were separately raised in rabbits against excretory/secretory (ES) antigens of both the flukes under study. An overall 70% buffalo faecal samples were tested positive for G. crumenifer and 75% for G. explanatum in Aligarh region. The ELISA results reflected higher infection intensity among individual buffaloes that was also observed at necropsy. Using the respective homologous hyperimmune antiserum, 55% buffaloes tested positive for G. crumenifer and 65% positive for G. explanatum in immunodot assay. Further, the faecal samples with high absorbance values in ELISA and strong immunodot reaction tested positive in CCIEP. The analysis of CCIEP result revealed two and one precipitin bands in G. crumenifer and G. explanatum respectively, indicating prominent antigenic differences in the coproantigens of these two parasites. Taken together, it is suggested that polyclonal antibodies could be conveniently used for the detection of coproantigens by ELISA and immunodot methods, particularly during the non-egg producing phase of the seasonally regulated reproductive cycle of the rumen amphistome G. crumenifer. It is concluded that the coproantigen detection is a good alternative over conventional method for the diagnosis of amphistomosis in livestock; however, further studies are required on a larger sample size of field buffaloes to augment the reproducibility of the present results.  相似文献   

Apigenin-induced suicidal erythrocyte death     

Zbidah M  Lupescu A  Jilani K  Fajol A  Michael D  Qadri SM  Lang F 《Journal of agricultural and food chemistry》2012,60(1):533-538

Apigenin, a flavone in fruits and vegetables, stimulates apoptosis and thus counteracts cancerogenesis. Erythrocytes may similarly undergo suicidal cell death or eryptosis, characterized by cell shrinkage and phosphatidylserine exposure at the cell surface. Triggers of eryptosis include increase of cytosolic Ca(2+) activity ([Ca(2+)](i)), ceramide formation and ATP depletion. The present study explored the effect of apigenin on eryptosis. [Ca(2+)](i) was estimated from Fluo3-fluorescence, cell volume from forward scatter, phosphatidylserine exposure from annexin V binding, hemolysis from hemoglobin release, ceramide utilizing antibodies, and cytosolic ATP with luciferin-luciferase. A 48 h exposure to apigenin significantly increased [Ca(2+)](i) (≥ 1 μM), increased ceramide formation (15 μM), decreased ATP concentration (15 μM), decreased forward scatter (≥ 1 μM), and increased annexin V binding (≥ 5 μM) but did not significantly modify hemolysis. The effect of 15 μM apigenin on annexin V binding was blunted by Ca(2+) removal. The present observations reveal novel effects of apigenin, i.e. stimulation of Ca(2+) entry, ceramide formation and ATP depletion in erythrocytes with subsequent triggering of suicidal erythrocyte death, paralleled by cell shrinkage and phosphatidylserine exposure.  相似文献   

Effect of certified health programs on the sale price of beef calves marketed through a livestock videotape auction service from 1995 through 2005     

King ME  Salman MD  Wittum TE  Odde KG  Seeger JT  Grotelueschen DM  Rogers GM  Quakenbush GA 《Journal of the American Veterinary Medical Association》2006,229(9):1389-1400

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Studies on the inactivation of white spot syndrome virus of shrimp by physical and chemical treatments, and seaweed extracts tested in marine and freshwater animal models   总被引：1，自引：0，他引：1  

Balasubramanian G  Sudhakaran R  Syed Musthaq S  Sarathi M  Sahul Hameed AS 《Journal of fish diseases》2006,29(9):569-572

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Mechanisms and molecular approaches for heat tolerance in rice (Oryza sativa L.) under climate change scenario     

Syed Adeel Zafar  Amjad Hameed  Muhammad Amjad Nawaz  Wei MA  Mehmood Ali Noor  Muzammil Hussain 《农业科学学报》2018,17(4):726-738

Rice, a staple cereal crop in many parts of the world, has been confronted with multiple environmental stresses including high temperature, negatively impacts the booting as well as anthesis growth stages. The situation is further complicated by the changing climatic conditions, resulting in gradual escalation of temperature as well as changing the rainfall pattern and frequency, thus raising a concern of food security worldwide. The situation can be combat by developing rice varieties with excellent genetics with improved morpho-physiological, biochemical, and molecular mechanisms, together can minimize the adverse effects of heat stress. Here, several strategies (encompassing genetic and genomic, and mechanisms involved) for mitigating the impact of high temperature on rice have been discussed. Finally, the utilization of genomic knowledge in augmenting the conventional breeding approaches have been comprehensively elaborated to develop heat tolerant germplasm.  相似文献   

Effect of protection against hot climate on growth performance,physiological response and endocrine profile of growing lambs under semi-arid tropical environment     

De  Kalyan  Kumar  Davendra  Singh  Anoop Kumar  Kumar  Kamal  Sahoo  Artabandhu  Naqvi  Syed Mohammed Khursheed 《Tropical animal health and production》2017,49(6):1317-1323

In the hot semi-arid tropical region, extreme summer is a major constraint in sheep production. The growth performance of growing lambs is impaired during the summer. Therefore, the present study was conducted to assess the effect of protection against hot climate on growth performance, physiological response, and endocrine profile of growing lambs under semi-arid tropical environment. All the data in the experiment were presented as mean ± SE. Thirty Malpura lambs with the age of 122.7 ± 6.05 days and body weight of 19.52 ± 0.42 kg were allotted into three groups, viz. G1 (control, lambs kept in open area under tree shade), G2 (lambs kept in conventional asbestos-roofed shed), and G3 (lambs kept in designed shed). The allotment was based on their initial body weight so that the mean body weight of each group was similar. In all three types of protection, lambs were provided with sufficient space to move and social interaction. In asbestos-roofed shed (G2), all the four sides from ground to the roof were fenced with strong galvanized iron chain link. But in G3, all the four sides were constructed in a manner that there was 0.13 m air space between inner and outer solid brick columns of the wall up to 1.37 m height, and rest up to the roof was fenced with bamboo splint net. The air space between the two columns of the wall was filled with sand, and it was kept in moist condition by continuous water drips which provide extra evaporative cooling. The designed shed was basically constructed with bamboo. Tree shade was assured under the natural shades of large trees. The shaded area was protected by wire fences. The experiment was conducted for 45 days during very high temperature (May–June). The lambs were provided with ad libitum green fodder, dry roughage, 300 g concentrate, and ad libitum drinking water. The respiration rate at morning and afternoon, pulse rate at morning and afternoon and rectal temperature at afternoon was significantly (P < 0.05) lower in lambs of G3 as compared to other groups. The final body weight did not differ significantly between the groups, but average daily gain (g/day) was higher in G3 (150.06 ± 11.13) as compared to the G1 (109.69 ± 18.10). The feed conversion rate (FCR) was significantly (P < 0.05) better in G3 (5.49 ± 0.08) as compared to G1 (7.65 ± 0.08) and G2 (6.60 ± 0.08). The hemoglobin level was significantly (P < 0.05) higher in G1. The endocrine profile did not vary significantly (P > 0.05) among the groups, but insulin-like growth factor-1 (IGF-1) was higher in G3. It can be concluded from this study the lambs provided with better protection during summer remained in more comfortable condition, showed better FCR, and although not statistically significant showed better growth performance.

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