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1.
Syed Jawad Ahmad Shah Shaukat Hussain Musharaf Ahmad Farhatullah Iftikhar Ali Muhammad Ibrahim 《Journal of General Plant Pathology》2011,77(3):174-177
Fifty wheat varieties along with Jupateco-73 and Morocco were studied for the expression of leaf tip necrosis (LTN), a trait
linked with the durable rust resistance gene pair Lr34/Yr18. LTN was frequent (i.e., ≥6) in nine replications of a field experiment over 3 years in 17 genotypes, and the varieties were
considered positive for LTN. In molecular analyses of these varieties, having relative severity values up to 78 for yellow
rust and 45 for leaf rust, the 150-bp Lr34/Yr18-linked allele was consistently amplified. Expression of LTN in six of nine replications is an appropriate threshold for predicting
the presence of Lr34/Yr18 gene pair, and genotypes can be selected using this trait. 相似文献
2.
The antimicrobial metabolites 2,4-diacetylphloroglucinol (2,4-DAPG) and pyoluteorin contribute to the ability of Pseudomonas fluorescens strain CHA0 to control plant diseases caused by soil-borne pathogens. P. fluorescens strain CHA0 and its derivatives CHA89 (antibiotics-deficient) and CHA0/pME3424 (antibiotics overproducing) were investigated as potential biocontrol agents against Meloidogyne javanica the root-knot nematode. Exposure of root-knot nematode to culture filtrates of P. fluorescens under in vitro conditions significantly reduced egg hatch and caused substantial mortality of M. javanica juveniles. Nutrient broth yeast extract (NBY) medium amended with 2% (w/v) glucose or 1 mM EDTA markedly repressed hatch inhibition activity of the strain CHA0 but not that of CHA0/pME3424 or CHA89. On the other hand, NBY medium amended with glucose significantly enhanced nematicidal activity of the strain CHA0/pME3424. Neither glucose nor EDTA had an influence on the nematicidal activity of the strains CHA0 and CHA89. Under in vitro conditions, antibiotic overproducing strain CHA0/pME3424 and CHA0 expressed phl‘-’lacZ reporter gene but strain CHA89 did not. Expression of the reporter gene reflects actual production of DAPG. In general, CHA0/pME3424 expressed reporter gene to a greater extent compared to its wild type counterpart CHA0. Regardless of the bacterial strains, reporter gene expression was markedly enhanced when NBY medium was amended with glucose but EDTA had no such effect. A positive correlation between the degree of juvenile mortality and extent of phl‘-’lacZ reporter gene expression was also observed in vitro. Strain CHA0 produced zones of 4-6 mm on MM medium containing gelatin while strain CHA0/pME3424 and CHA89 did not. When MM medium containing gelatin was amended with 2% glucose of 1 mM EDTA size of haloes produced by the strain CHA0 reduced to 2 mm. Under glasshouse conditions aqueous cell suspension of the strains CHA0 or CHA0/pME3424 at various inoculum levels (107, 108 or 109 cfu ml−1) significantly reduced root-knot development. CHA89 caused significant reduction in galling when applied at 109 cfu ml−1. To better understand the mechanism of nematode suppression, split root bioassay was performed. Split-root experiments, that guarantee a spatial separation of inducing agent and a challenging pathogen, showed that soil treatment of one half of the root system with cell suspension of CHA0 or CHA0/pME3424 resulted in a significant systemic induced resistance leading to reduction of M. javanica infection of tomato roots in the non-baterized nematode treated half. The results clearly suggest that the antibiotic 2,4-DAPG from P. fluorescens CHA0 act as the inducing agents of systemic resistance in tomato roots. Populations of CHA0 and its derivatives declined progressively by 10-fold between first and fourth harvests (0-21 days after inoculation). However, bacterial populations increased at final harvest (28 days after application). 相似文献
3.
研究0.2%噻苯隆可溶液剂提高‘脆皮’金桔产量和品质的效果,在金桔的幼果期和果实膨大期喷施不同质量分数(2、3、4、6 mg/kg)的0.2%噻苯隆可溶液剂,测定其对金桔产量和品质等指标的影响。与空白对照比较,喷施0.2%噻苯隆可溶液剂的金桔单株产量增加了16.5%~23%,果实质量增加10.2%~12.2%,果肉的可溶性物含量增加了5.9%~6.3%,维生素C含量增加了8.7%~9.3%,含糖量增加了7.9%~9.0%,可滴定酸含量下降了8.1%~13.5%。0.2%噻苯隆可溶液剂对金桔产量及品质有显著的提高和改善作用,当药液剂量达到4 mg/kg时,金桔的各项指标均达到较高水平,且与最大值无显著差异,因此推荐生产中使用0.2%噻苯隆可溶液剂的适宜浓度为3~4 mg/kg。 相似文献
4.
Isaac M. OSUGA Carolyne C. WAMBUI Shaukat A. ABDULRAZAK Toshiyoshi ICHINOHE Tsutomu FUJIHARA 《Animal Science Journal》2008,79(5):582-589
The feeding value of five browse foliages (Acacia brevispica, Acacia mellifera, Berchemia discolor, Zizyphus mucronata and Maerua angolensis) grown in semiarid area of Kenya were evaluated. Their chemical composition including polyphenolics and in vitro gas production characteristics were determined. The biological activity of the polyphenolics was assessed as the increases in gas production profiles and in vitro true dry matter (DM) and organic matter (OM) digestibility after in vitro incubation with or without addition of polyethylene glycol (PEG) as a tannin binding reagent. The intake and palatability ranking of the browse foliages by goats and sheep were also investigated. The browse foliages had variable crude protein content (149.5–248.6 g/kg DM) and variable content of neutral detergent fiber (205.1–424.0 g/kg DM). The content of total extractable tannins was generally low (2.4–34.8 g/kg DM). At 24 h of incubation, Z. mucronata produced the highest gas volume, while after 48 h of incubation, B. discolor produced the highest gas volume. M. angolensis had the least gas production potential within the browse foliages. Addition of PEG increased gas production except in A. mellifera and M. angolensis. However, PEG addition did not have any significant effect on in vitro true DM and OM digestibility except in B. discolor, which decreased. The rank order of preference (highest to least) for goats was A. brevispica, Z. mucronata, B. discolor, A. mellifera and M. angolensis while the rank order of preference for sheep was A. brevispica, B. discolor, A. mellifera, Z. mucronata and M. angolensis. The goats had higher intakes of all the browse foliages than sheep. The result of this study highlights the higher feeding value of the browse species as supplemental feed with low quality basal diet with both of animal species except M. angolensis. 相似文献
5.
Nasrullah Khan Syed Shahid Shaukat Moinuddin Ahmed Muhammad Faheem Siddiqui 《林业研究》2013,24(2):205-216
We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quarter (PCQ) method while understory vegetation was sampled in 1.5-m circular quadrats. Cedrus deodara is the national symbol of Pakistan and was dominant in the sampled communities. Because environmental variables determine vegetation types, we analyzed and evaluated edaphic and topographic factors. DCA-Ordination showed the major gradient as an amalgam of elevation (p<0.05) and slope (p<0.01) as the topographic factors correlated with species distribution. Soil variables were the factors of environmental significance along DCA axes. However, among these factors, Mg2+ , K + and N2+ contributed not more than 0.054% 0.20% and 0.073%, respectively, to variation along the first ordination axis. We conclude that the principal reason for weak or no correlation with many edaphic variables was the anthropogenic disturbance of vegetation. The understory vegetation was composed of perennial herbs in most communities and was most dense under the tree canopy. The understory vegetation strongly regulates tree seedling growth and regeneration patterns. We recommend further study of the understory vegetation using permanent plots to aid development of forest regeneration strategies. 相似文献
6.
Nutritive value of selected grasses in North Sumatra, Indonesia 总被引：1，自引：0，他引：1
EVITAYANI Lili WARLY Armina FARIANI Toshiyoshi ICHINOHE Shaukat A. ABDULRAZAK Maki HAYASHIDA Tsutomu FUJIHARA 《Animal Science Journal》2005,76(5):461-468
The nutritive values of seven native grass species collected in North Sumatra, Indonesia, during dry and rainy seasons were evaluated. The chemical composition, in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD), in vitro crude protein digestibility (IVCPD), macro mineral concentrations of calcium, phosphorus and magnesium, in vitro gas production profile and metabolizable energy (ME) content of the grasses varied greatly among species and seasons. The crude protein content ranged from 6.6 (Andropogon gayanus) to 16.2% dry matter (Cynodon plectostachyus) in the rainy season, with a significant (P < 0.05) reduction in the dry season. Data on the fiber fraction showed that the grasses contained more neutral detergent fiber (NDF) and acid detergent fiber (ADF) in the dry season and it significantly (P < 0.05) decreased in the rainy season, except for Panicum maximum and Pennisetum purpureum for NDF content and C. plectostachyus, P. maximum and Brachiaria decumbens for ADF content. Data on the mineral concentration showed that C. plectostachyus in the dry and rainy seasons had a higher calcium content than those of other species. The overall means of the seven grasses for IVDMD, IVOMD and IVCPD were significantly higher (P < 0.05) in the rainy season than in the dry season. The in vitro gas production and ME concentration were numerically higher in the rainy season than in the dry season. In conclusion, the nutritive value of the observed grasses in North Sumatra was relatively higher during the rainy season compared with the dry season. Among the species of grass, P. purpureum and C. plectostachyus had a higher nutritive value in both the dry and rainy seasons. 相似文献
7.
We investigated the phytosociology, structure and dynamics of Pinus roxburghii in 40 stands in northern areas of Pakistan by using cluster analysis （Ward’s agglomerative clustering） and ordination （Non-metric Multidimensional Scaling）. Cluster analysis revealed three major groups associated with specific environmental characteristics： （1） P. roxburghii （2） Pinus-Quercus baloot and （3） Pinus-Olea ferruginea community types. NMS-ordination showed the major gradient as an amalgam of elevation （r2=0.441, p＆lt;0.01） and slope （r2=0.391, p＆lt;0.05） as the two topographic factors correlated with species distribution. The first ordination axis also showed positive correlation with soil variables like pH and electrical conductivity, suggesting that soil chemistry was related to topographic characteristics and probably acted as a secondary gradient. We also examined size class distributions, age structures and growth rates of the three communities in order to describe community development and dynamics. Total tree density was 14700 plants/ha, with P. roxburghii having a relative density of 82%to 100%. Density of juve-nile and total density and basal area of the subordinate tree species were low. The low density of trees in the smallest diameter size-class sug-gested that the recruitment of small P. roxburghii plants into the adult population may be lower than the required replacement rate for the stands. Pooled size-class distributions for the species showed a multimo-dal pattern with some regeneration gaps. Browsing, heavy logging and＆amp;nbsp;other anthropogenic activities were the overriding factors responsible for the poor recruitment of P. roxburghii. We concluded from the age struc-ture that the forests were characterized by the dominance of young trees. Growth rate analysis revealed that P. roxburghii was the fastest growing species among the conifers species in Pakistan. In view of its relatively fast growth and longevity, P. roxburghii seems to be a suitable choice for short-t 相似文献
8.
Sadiq Rehan Husain Tahir Al-Zahrani A. M. Sheikh Anwar Khalil Farooq Shaukat 《Water, air, and soil pollution》2003,143(1-4):41-63
The objective of this study is to examine the reuse of wastewaterfor beneficial purposes. To accomplish this objective, the efficiency of slow sand filters in removing total coliforms (TC) was studied using a probabilistic method. Three pilot scale slowsand filters were constructed at Alkhobar wastewater treatment plant, Dhahran, Saudi Arabia. The removal efficiency of filters was estimated under different operating control parameters, which included filtration rate (q), sand bed depth (d) and sand grain size (c). The Type III extreme value distribution best fitted theremoval efficiency data. A multiple linear regression analysis was performed to develop a relationship for mean removal efficiency as a function of control parameters. The predicted mean response and experimental results of previous studies werecompared to validate the empirical regression model. The controlparameters and influent concentrations of total coliform were used in Monte Carlo (MC) simulations for calculating the reliability index (β). The reliability index and corresponding risk were calculated for lognormally distributedsafety margins (SM). An effluent standard of 100 total coliform/100 mL was defined as capacity of the filter to ascertainthe risks of exceedence, which was approximately less than 50 for95% of the time. Pre and/or post disinfection would be necessaryto meet the stipulated effluent standards for unrestricted agriculture use. 相似文献
9.
The available information on Pseudomonas biocontrol inoculants on the non-target fungal and nematode community is scant. The current paper addresses this issue and investigates the effects of biocontrol agents Pseudomonas aeruginosa IE-6 and IE-6S+ (previously shown to suppress several soil-borne plant pathogens) on soil microfungi and plant-parasitic nematodes as well as on the root-knot development and growth of tomato (Lycopersicon esculentum). Furadan, a granular nematicide was included as a treatment for comparative purposes. Treatments were applied to soil at the start of each 52-day-long tomato growth cycle, and their effects on the composition and diversity of rhizosphere and endophytic microfungi and plant-parasitic nematodes were examined at the end of first and fourth growth cycle. Several diversity indices were employed to assess community diversity. A total of 16 genera comprising 23 microfungal species were isolated from the tomato rhizosphere. The most abundant fungal species belonged to the genera Aspergillus, Fusarium, and Penicillium. With a few exceptions, fungi were neither exclusively inhibited nor specifically promoted by the application of treatments at any of the growth cycles studied. However, Paecilomyces lilacinus, an egg and female parasite of root-knot nematode, though exclusively absent in the controls was isolated from the treatments. Both general diversity and equitability of rhizosphere microfungi were greater at first compared to the fourth growth cycle while species richness remained uninfluenced across the growth cycles and treatments. However, Furadan and IE-6S+ treatments considerably abated general diversity and equitability. Of the microfungal species isolated from the rhizosphere seven were also recovered from surface-sterilized root tissue of tomato suggesting that all the endophytes are primarily rhizosphere organisms. Diversity of endophytic fungi was consistently lower compared with that of the rhizosphere. Both general diversity and equitability declined in all three treatments relative to controls in the root tissue but species richness remained unaltered. Diversity and equitability of plant-parasitic nematodes in soil were reduced by all three treatments over the controls at fourth growth cycle whilst species richness did not change at either growth cycle. The biocontrol agents significantly reduced root-knot development and enhanced shoot growth of tomato over the controls. The possible implications of fungal composition and abundance because of biocontrol by Pseudomonas application are discussed. 相似文献
10.