The effect of hybridization on thermal and mechanical properties of glass/oxidized PAN fibers-polymer composites     

Hossein Ebrahimnezhad-Khaljiri  Reza Eslami-Farsani 《Fibers and Polymers》2015,16(11):2445-2450

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Water quality influences the presence of Streptococcus agalactiae in cage cultured red hybrid tilapia,Oreochromis niloticus × Oreochromis mossambicus          下载免费PDF全文

Mohammad Noor Azmai Amal  Mohd Zamri Saad  Abdullah Siti Zahrah  Abd Rashid Zulkafli 《Aquaculture Research》2015,46(2):313-323

Attempts were made to identify the association between water quality parameters and the presence of Streptococcus agalactiae in cage cultured red hybrid tilapia, Oreochromis niloticus × O. mossambicus. Fish from commercial floating net cage‐culture systems in a river and lake were randomly sampled over a 24‐month period. Swabs from the brains, eyes and kidneys were streaked directly onto blood agar to isolate S. agalactiae. Water temperature, dissolved oxygen, pH, clarity, ammonia, nitrite, sulfide, rate of water flow and depth of water at sampling sites were measured at the same time of fish sampling. The prevalence of fish that were cultured positive to S. agalactiae was significantly higher in lake compared with river. The length and weight of the infected fish were between 9 and 33 cm, and between 20 and 760 g respectively. There was a significant and positive strong correlation between the presence of S. agalactiae and fish mortalities in lake. All water quality parameters showed significant differences between river and lake. However, only water temperature, clarity and pH of lake and the ammonia, temperature and dissolved oxygen in river showed significant correlation with the presence of S. agalactiae in the cultured fish. It was concluded that several unfavourable water quality in the fish farm influencing the presence of S. agalactiae in cultured red hybrid tilapia.  相似文献   

Sublethal effects of environmentally relevant run‐off concentrations of glyphosate in the root zone of Ludwigia peploides (creeping water primrose) and Polygonum hydropiperoides (smartweed)     

Lyndsay E. Saunders  Reza Pezeshki 《Weed Biology and Management》2014,14(4):242-250

As one of the most widely applied agricultural chemicals in the world, glyphosate has many effects on the environment. The present study quantified plant responses to exposure by glyphosate through the root zone for a range of concentrations (0, 10, 100 and 1000 μg L^?1). Ludwigia peploides and Polygonum hydropiperoides were grown in a greenhouse and given a single exposure to glyphosate via the root zone. The growth and physiological parameters were measured before exposure and for 18 days postexposure. The growth variables that were measured included the relative growth rate, stem length increase, biomass and root‐to‐shoot‐ratios. The physiological variables that were measured were the chlorophyll content index and chlorophyll fluorescence. The data analyses revealed that the root‐zone glyphosate affected some of the measured variables in P. hydropiperoides more than for L. peploides. Polygonum hydropiperoides showed a significant decrease in the root‐to‐shoot ratios for the 100 μg L^?1 treatment, compared to the 10 μg L^?1 treatment. The chlorophyll content index of the treated plants was significantly reduced in P. hydropiperoides, compared to the untreated plants on Days 7 and 18. Ludwigia peploides was affected only on the day after exposure, with the chlorophyll fluorescence parameters being significantly less for the 1000 μg L^?1 treatment, compared to the 10 μg L^?1 treatment. Glyphosate‐treated P. hydropiperoides showed a decreased chlorophyll content and reduced chlorophyll fluorescence parameters. In contrast, L. peploides showed a decrease in the chlorophyll fluorescence parameters but no reduction in its chlorophyll content. In addition to demonstrating the adverse effects of root exposure to glyphosate for the study species, these data help to partially explain the highly invasive and persistent nature of L. peploides in marginal aquatic environments, such as agricultural ditches.  相似文献   

The vacuoles containing multivesicular bodies: a new observation in interaction between Ustilago esculenta and Zizania latifolia     

Jing-ze Zhang  Fu-qiang Chu  De-ping Guo  Mohammad Reza Ojaghian  Kevin D Hyde 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(1):79-91

Ustilago esculenta infects Zizania latifolia plants and induces swelling on their upper culms. As an edible aquatic vegetable, these swellings are called jiaobai (white bamboo). The process of fungal development in Huijiao (grey bamboo) plants from seedlings to upper culm swelling was investigated using knife cut tissues, light and electron microscopy. All Huijiao plants were relatively taller than all jiaobai plants and in knife-cut sections sori development differed after culm swelling in Huijiao plants. Light microscope examination show that hyphae were both intracellular and intercellular, forming hyphal aggregations, and were more abundant in nodes than in internodes. Rapid increase of hyphal aggregations occurred 15 days before culm swelling, causing the death of abundant host cells, and hyphal aggregations differentiated into sori initiates. Ultrastructural observation showed that intracellular hyphae at the interface of fungus-host interaction were encased in a sheath with outer electron-opaque and inner electron-dense layer. Scale-like material and membrane-bounded vesicles were often present in an outer electron-opaque matrix of the sheath. Vacuoles, lipid globules (LGs) and multivesicular bodies (MVBs) were occasionally seen in these fungal cells. In summer, abundant electron-dense MVBs, LGs and fewer vacuoles containing MVBs were present in a fungal cell. As the temperature decreased, some MVBs became electron-opaque, some internal vesicles were also electron-opaque, and subsequently, the MVBs disappeared, leaving irregular remnant materials in vacuoles. During the rapid increase in hyphal aggregations, the irregular remnants of material within the vacuoles disappeared and LGs were rare. At the beginning of sori development, LGs once again became abundant in the cells of hyphal aggregation. The process of sorus and teliospore development was observed systematically and relationships between each developmental stage examined from knife cut tissues, and cytological and ultrastructural sections. Sorus development occurred with the commencement of upper culm swelling and differed in the same tissues. Teliospore development was also uneven in a sorus. The inner region of a sorus developed earlier than the outer part.  相似文献   

Application of half-sib mating for genetic analysis of forage yield and related traits in Bromus inermis     

Bahram Araghi  Mohammad Barati  Mohammad Mahdi Majidi  Aghafakhr Mirlohi 《Euphytica》2014,196(1):25-34

Despite efforts made, forage yield of smooth bromegrass has increased slowly over the last 50 years of breeding. It therefore seems necessary to investigate more on the genetic basis of agro-morphological traits in this cool-season, highly drought resistant grass. The present study was aimed at estimation of total genetic variance, narrow-sense heritability, general combining ability, phenotypic and genotypic correlation among different quantitative traits in half-sib (HS) families derived from polycross of 25 smooth bromegrass genotypes that were mainly originated from Iran. Families differed significantly for all of the agro-morphological and quality traits measured. Narrow sense heritability ( ${\text{h}}_{\text{n}}^{2}$ ) ranged from about 0.2 (plant height) to 0.7 (day to inflorescence emergence and day to anthesis). Moderate to high heritability for forage dry matter yield (0.42) indicates that phenotypic selection for this trait can be successful. A wide range of general combining ability was observed for most of the studied traits, especially those related to forage yield. Relatively low genetic variation and heritability for crude protein and also negative correlation of this trait with forage yield, indicates a low probability of improving forage yield and quality simultaneously.  相似文献   

Large-scale high throughput screening of sugar beet germplasm using a nanobiosensor and its comparison with ELISA method for resistance to Polymyxabetae     

Fatemeh Hassanzadeh Davarani  Hossein Safarpour  Mohamamd Reza Safarnejad  Afshin Mohsenifar  Seyed Bagher Mahmoudi  Mojdeh Kakoueinejad  Meisam Tabatabaei 《Euphytica》2014,200(3):389-399

Identification of resistance resources of sugar beet germplasm against Polymyxa betae has always been a critical concern among sugar beet breeders. In the present study, two different methods including the DAS-enzyme-linked immunosorbent assay (ELISA) test and a nanobiosensor method based on florescent resonance transfer energy (FRET) were compared in order to achieve resistant germplasm. More specifically, 58 sugar beet germplasm as well as two negative and two positive controls were cultivated in infested soil under greenhouse conditions. The contamination level or in another words sensitivity and specificity observed based on the ELISA readings was inaccurately lower in comparison with the investigated nanobiosensor. Moreover, the nanobiosensor was 70 folds less time consuming compared to the ELISA method, for the immuno-reaction was much faster and no sample treatment steps were required. As a result, the quantum dots-FRET-based nanobiosensor investigated herein could well suit the task of everyday screening of resistance resource and could be efficiently used in breeding programs.  相似文献   

Analysis of mode of inheritance of Fusarium wilt resistance in castor (Ricinus communis L.)     

Anjani Kammili  Mohammad A. Raoof 《Plant Breeding》2014,133(1):101-107

Castor (Ricinus communis L.) is an important industrial oilseed crop grown worldwide. Wilt caused by Fusarium oxysporum f.sp. ricini is a devastating disease in castor. The inheritance mode of wilt resistance was investigated. The F₁, F₂ and backcross generations of four crosses involving four resistant and three susceptible parents were developed. The role of digenic (R¹ and R²) epistatic interactions on wilt resistance was confirmed. The 15 : 1, 9 : 7 and 13 : 3 ratios indicated duplicate dominant, duplicate recessive and dominant and recessive epistatic interactions, respectively. Castor parents used in the crosses exhibited varied inheritance modes. All generations of a cross exhibited similar inheritance mode when parents were comparable. However, generations varied in inheritance mode when parents were not comparable in inheritance mode. These results would have practical interest when decisions are required regarding the choice of parents and methodology in resistance and hybrid breeding. The results also provided a basis for investigating molecular genetics of wilt resistance mechanisms.  相似文献   

Genetic analysis of salt tolerance at seedling and reproductive stages in rice (Oryza sativa)     

Reza Mohammadi  Merlyn S. Mendioro  Genaleen Q. Diaz  Glenn B. Gregorio  Rakesh K. Singh 《Plant Breeding》2014,133(5):548-559

Salinity is a major abiotic stress that limits rice production across rice areas as high‐yielding modern rice varieties are generally sensitive to salt stress. The study was conducted to deduce heritability and combining ability estimates of rice for various morphological and physiological traits using a 7 × 7 full‐diallel‐cross analysis at seedling and reproductive stages. The salinity stress treatment was 12 dS m^?1 at the seedling stage and 8 dS m^?1 at the reproductive stage. Diallel analysis revealed high for salinity tolerance scores and shoot height, moderate for shoot dry weight and root dry weight and low for Na⁺ and K⁺ concentrations and K⁺/Na⁺ ratio. The low‐to‐moderate narrow‐sense heritability for number of panicles, number of fertile spikelets, grain weight, spikelet fertility and K⁺/Na⁺ ratio suggests a large breeding population and delayed selection for tolerance until later generations. Significant maternal effects indicate that selection of the female parent is very important for desired trait development. The results of this study confirmed that salinity tolerance at the seedling and reproductive stages is regulated by a different set of genes that could be pyramided using different donors to enhance the level of tolerance.  相似文献   

Growth analysis of rhizomania infected and healthy sugar beet     

Javad Rezaei  Mohammad Bannayan  Ahmad Nezami  Mohsen Mehrvar  Bagher Mahmoodi 《Journal of Crop Science and Biotechnology》2014,17(2):59-69

Viral disease of rhizomania is one of the most important diseases of sugar beet all over the world. The disease significantly has reduced the yield and quality of sugar beet, and has imposed high economic loss to farmers. Long-term breeding programs to introduce tolerant cultivars are the only chance of avoiding further yield losses. This study tried to measure and analyze the growth of shoots and roots of rhizomania-tolerant and -susceptible sugar beet with the aim of providing information for modeling of the rhizomania effects on the growth of sugar beet. Growth indices were used for analyzing, quantification, and time-course of sugar beet growth under infested and non-infested soils conditions. A 2-year experiment was conducted using four sugar beet cultivars in 2010 and 2011 in Mashhad, Iran. The results of this study showed that under infested soils, root dry matter and leaf area index of the susceptible cultivars in comparison to tolerant cultivars were lower by 57 and 24%, respectively. In addition, crop growth rate and net assimilation rate of susceptible cultivars were affected by rhizomania and were lower than in tolerant cultivars. On non-infested soil, the difference between dry matter and growth indices of susceptible and tolerant sugar beet cultivars was not significant. Rhizomania decreased green area and photosynthesis capacity and led to lower growth rate and dry matter production. Our study quantified the growth of rhizomania-infested sugar beet plants in comparison with non-infested plants and provided information to be used for modeling of the rhizomania effects on the growth of sugar beet.  相似文献   

Impacts of decentralized fish fingerling production in irrigated rice fields in Northwest Bangladesh     

Mohammad Mahfujul Haque  David C Little  Benoy K Barman  Md Abdul Wahab  Trevor C Telfer 《Aquaculture Research》2014,45(4):655-674

Rice field‐based fish seed production (RFFSP) has become established in parts of Northwest Bangladesh (NWB) as part of promoting improved rice‐based livelihoods. The impact of RFFSP on adopting households in terms of interactions of assets and other activities was assessed in a comparison of seed‐producing (RF; n = 60) and non‐seed‐producing (NRF; n = 58) households that were sampled randomly and ranked as poor, intermediate and better‐off. Adoption of RFFSP was not constrained by illiteracy of the household head, the size or ownership status of ponds, or lack of ownership of land or an irrigation pump. Poorer and intermediate households had smaller RF plots and lower production of fingerlings (kg per household) compared with the better‐off, although production efficiency (kg ha^?1) was higher. Restocking of fingerlings in RF household ponds increased productivity by 60% over NRF. Fish consumption of better‐off RF households exceeded NFR by 50%. Among the poor, seasonal benefits of income from sales and subsistence consumption of fingerlings were significant. Rice production in irrigated, and income in both irrigated and rain‐fed seasons was higher, and production costs lower, in riceplots producing fish than in rice‐only plots. Implications for supporting the innovation networks promoting and establishing RFFSP among rice growers, are discussed.  相似文献