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181.
By using Particle-Induced X-ray Emission (PIXE) technique, the effect of arsenic (As) on the mineral contents and translocation in the xylem of rice (Oryza sativa L. cv. ‘Akihikari’) was studied. The results suggest that exogenous As increased the concentrations of phosphorus (P), calcium (Ca) magnesium (Mg), sulfur (S), and manganese (Mn) in xylem, while the concentrations of potassium (K) remained unchanged. The highest concentration of As to the rice roots did not have any clear effect on the translocation of P, Ca, S, and chlorine (Cl) in the xylem, indicating that the increasing concentrations of the minerals may be due to a condensation effect, resulting from the repression of water movement in xylem by As-toxicity. Among the metal micronutrients, As decreased the concentrations and translocations of iron (Fe), zinc (Zn), and copper (Cu). 相似文献
182.
183.
Omidvar Farhadian Rahman Kharamannia Nasrollah Mahboobi Soofiani Eisa Ebrahimi Dorche 《Aquaculture Research》2014,45(7):1212-1223
Three different live diets, Eucyclops serrulatus, Ceriodaphnia quadrangula and equal combination of E. serrulatus copepodid and C. quadrangula, were offered to angelfish (Pterophyllum scalare) larvae viz 1‐week, 2‐week and 3‐week old at prey densities of 2, 5 and 10 individuals mL?1. Results showed that 1‐week‐old P. scalare larvae consumed E. serrulatus copepodid at a rate of 31.3–56.7 ind. h?1, C. quadrangula at 8.0–12.0 ind. h?1, and mixture of E. serrulatus and C. quadrangula at 20.7–40.7 ind. h?1. For 2‐week‐ and 3‐week‐old larvae, consumption rate increased accordingly. The electivity indices (E) of P. scalare (1‐week‐old larvae) for E. serrulatus copepodid were +0.18, +0.23 and +0.22 at prey densities of 2, 5 and 10 ind. mL?1 respectively. Tendency towards E. serrulatus copepodid consumption reduced by aging P. scalare as indicated by the E values for 2‐ and 3‐week‐old larvae. However, growth and survival of P. scalare larvae was greatest when fed on combination of copepod E. serrulatus and C. quadrangula. 相似文献
184.
Sajid Ali Marc Leconte Hidayatur Rahman Muhammad Shahab Saqib Pierre Gladieux Jérôme Enjalbert Claude de Vallavieille-Pope 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(2):275-290
Information on the pathogen virulence profile and diversity across locations is crucial for host germplasm improvement and deployment. The rapid acquisition of virulence to host resistance by the wheat yellow/stripe rust pathogen (Puccinia striiformis f.sp. tritici: PST), makes it crucial to know about its virulence and pathotype diversity. Recent studies have shown the plausible centre of origin of the pathogen in the Himalayan region, with Pakistan being the most ancestral to all other worldwide populations. To assess the status of virulence and pathotype diversity in the Himalayan region of Pakistan, a set of 127 PST infected wheat samples from eight locations were collected, multiplied and pathotyped using a set of 36 differential lines from the world set, European and Chinese sets, and 9 Avocet Yr isolines. Virulence (Vr) was recorded to 18 out of 24 tested yellow rust resistance (Yr) genes, while a total of 53 pathotypes were detected out of 127 isolates tested. Virulence was found to the resistance genes rarely deployed in Pakistan (Vr8) or even worldwide level (Vr5), while virulence to Vilmorin 23 (Yr3+) was absent in Pakistan, which is common in Europe. None of the pathotypes was dominant across all locations, however, no clear spatial structuring was observed for the studied locations. Our results suggested a high virulence and pathotype diversity in line with the previously proposed potential role of sexual recombination in the temporal maintenance of PST in the Himalayan region of Pakistan. This information should be useful in host resistance gene improvement and deployment. 相似文献
185.
Mohammad Ziaur Rahman Seiji Uematsu Toru Takeuchi Kayo Shirai Yasushi Ishiguro Haruhisa Suga Koji Kageyama 《Journal of General Plant Pathology》2014,80(4):348-365
A new disease of rose was noticed in Chiba Prefecture of Japan in 1968, and the pathogen was initially identified as Phytophthora megasperma based on morphological characteristics. Similar Phytophthora isolates have since been collected from rose plants in Chiba, Kanagawa, and Shizuoka Prefectures. In 2005, several Phytophthora isolates were recovered from crowns of strawberry plants in Hokkaido Prefecture. These were considered to be members of a new species. In this study, we re-examined all these isolates using morphological and physiological studies and a multilocus phylogenetic analysis. The rose and strawberry isolates were mostly similar morphologically and physiologically, with some exceptions. The rose isolates differed significantly from P. megasperma sensu stricto and other related Phytophthora species. The rose and strawberry isolates had external proliferation of sporangia, characteristic funnel-shaped oogonia, predominantly paragynous antheridia, and fast growth rates of 10.5 mm/24 h at an optimum temperature of 28 °C. In the multilocus phylogenetic tree constructed using sequences from the rDNA ITS regions, rDNA LSU, and the translation elongation factor 1-α, β-tubulin and coxI genes, they formed a distinct monophyletic group in clade 7 with strong bootstrap support. The rose and strawberry isolates separated into two distinct groups. The results indicate that the rose and strawberry isolates constitute two separate species, designated here as Phytophthora nagaii and P. fragariaefolia. 相似文献
186.
A diversity arrays technology (DArT) map was constructed to identify quantitative trait loci (QTL) affecting seed colour, hairy leaf, seedling anthocyanin, leaf chlorosis and days to flowering in Brassica rapa using a F2 population from a cross between two parents with contrasting traits. Two genes with dominant epistatic interaction were responsible for seed colour. One major dominant gene controls the hairy leaf trait. Seedling anthocyanin was controlled by a major single dominant gene. The parents did not exhibit leaf chlorosis; however, 32% F2 plants showed leaf chlorosis in the population. A distorted segregation was observed for days to flowering in the F2 population. A linkage map was constructed with 376 DArT markers distributed over 12 linkage groups covering 579.7 cM. The DArT markers were assigned on different chromosomes of B. rapa using B. rapa genome sequences and DArT consensus map of B. napus. Two QTL (RSC1‐2 and RSC12‐56) located on chromosome A8 and chromosome A9 were identified for seed colour, which explained 19.4% and 18.2% of the phenotypic variation, respectively. The seed colour marker located in the ortholog to Arabidopsis thaliana Transparent Testa2 (AtTT2). Two QTL RLH6‐0 and RLH9‐16 were identified for hairy leaf, which explained 31.6% and 20.7% phenotypic variation, respectively. A single QTL (RSAn‐12‐157) on chromosome A7, which explained 12.8% of phenotypic variation was detected for seedling anthocyanin. The seedling anthocyanin marker is found within the A. thaliana Transparent Testa12 (AtTT12) ortholog. A QTL (RLC6‐04) for leaf chlorosis was identified, which explained 55.3% of phenotypic variation. QTL for hairy leaf and leaf chlorosis were located 0–4 cM apart on the same chromosome A1. A single QTL (RDF‐10‐0) for days to flowering was identified, which explained 21.4% phenotypic variation. 相似文献
187.
188.
渭干河-库车河三角洲绿洲土地资源合理利用对策分析 总被引:4,自引:0,他引:4
本文对干旱区内陆河流域下游具有代表性的渭干河—库车河三角洲绿洲土地资源特征和存在的问题进行了详细的分析 ,分析表明 ,土地资源数量大、质量差、利用率低 ,土壤类型多 ;草场面积大、质量差 ;森林覆盖率低、疏林、灌木林比重大 ;土地利用中存在结构不合理 ,特别是林业、畜牧业比重偏低 ,绿肥和饲料作物面积过小 ;土壤次生盐渍化严重、土壤肥力下降 ,经营管理粗放、单产水平不高 ;草场面积锐减 ,森林资源破坏严重 ,保护绿洲的能力下降。在此基础上 ,提出了优化农业用地结构 ,提高土地利用综合效益 ;增加对农业用地开发利用的投入 ,促进农业用地由粗放型向集约型的转变 ;保护和更新胡杨林 ;保护和建设草场 ;大力治理盐碱 ;发展节水灌溉农业 ,提高水资源利用效益 ;扩大绿洲规模 ,加快城市化建设等持续合理利用土地资源的对策。 相似文献
189.
190.
Fiber quality is very important for all the steps of the textile area. Underwater shock wave has been utilized for metal,
wood, food processing and medical applications and renewed and increased application during the last decade. The main object
of this study, is to demonostrate underwater shock wave as a surface treatment of natural fibers such as jute and cotton in
form of yarn and to report characterized properties of the treated fibers. The underwater shock wave was generated by the
explosion of the detonation fuse in the water tank. The process of bubble generation and expansion inside the water results
in the formation of shock wave. Natural fibers were exposed to shock wave treatment depending on the different pressures and
detonatinon fuse separation distance. After shock-loading, fibers were selected for physicomechanical and physicochemical
tests such as Scaning Elecron Microscopy (SEM) analysis, breaking strength, moisture behavior, permeability and wicking test.
The maximum effect with improved moisture content, permeabilty and wicking properties were observed from 100 MPa. The treated
fiber showed high performance necessary for use in woven and non woven purpose. 相似文献