Kinetics of the OH Reaction with Methyl Chloroform and Its Atmospheric Implications

The rate coefficients for the reaction of hydroxyl (OH) radicals with methyl chloroform (CH(3)CCI(3)) were measured between 243 and 379 kelvin with the pulsed photolysis-laserinduced fluorescence method. The measured rate coefficients at 298 and 277 kelvin were approximately 20 and approximately 15%, respectively, lower than earlier values. These results will increase the tropospheric OH concentrations derived from the CH(3)CCI(3) budget analysis by approximately 15%. The predicted atmospheric lifetimes of species whose main loss process is the reaction with OH in the troposphere will be lowered by 15% with consequent changes in their budgets, global warming potentials, and ozone depletion potentials.     

Where have all the sawfishes gone? Perspectives on declines of these Critically Endangered species in Sri Lanka

1. All five species of sawfishes (family Pristidae) are amongst the most threatened marine fishes in the world, with steep population declines and local extinctions documented across their ranges.
2. Sawfishes have featured in Sri Lankan species checklists since 1889. However, landing records are extremely rare and little information is available on their status, diversity, and recent occurrences.
3. Interviews were conducted with 300 fishers and 10 fish traders. Only 39% of fishers (n = 118) could identify sawfishes, 37% had seen sawfishes (although half not since 1992), and only 10.7% had ever caught one. No respondents under 30 years could identify sawfishes. Older respondents (>50 years) were more likely to have caught sawfishes and reported seeing them frequently until 30 years ago, while younger respondents had only seen them at landing sites and, at most, once or twice in their life. Only 10 respondents had seen a sawfish in the last decade, suggesting that sawfishes were relatively abundant in the past but that populations have drastically declined.
4. Of the 32 respondents who had caught sawfishes, 30 reported declining numbers and attributed it to fishing pressure. These steep declines coincide with the time of increased fishing effort, the development of the aquaculture industry, and resulting degradation of coastal habitats in the 1980–1990s.
5. Overall, sawfishes had little cultural significance although fishers had specific names for the different species occurring here and rostra were sometimes donated to Catholic churches for ‘good luck’. Landed sawfishes were primarily sold for meat and traders appeared unaware of the high value of fins.
6. It is likely that sawfishes are now functionally extinct as a component of coastal ecosystems in Sri Lanka. Immediate action including species-specific legislation and critical habitat protection is urgently needed to provide remaining sawfishes and other sharks and rays with a fighting chance.

     

Population structure,gene flow and genetic diversity analyses based on agro-morphological traits and microsatellite markers within cultivated and wild germplasms of okra [Abelmoschus esculentus (L.) Moench.]

Genetic Resources and Crop Evolution - Okra [Abelmoschus esculentus (L.) Monech.] is an annual herb of the family Malvaceae and has tremendous nutritional and industrial potential. However, the...     

Rheology and stability of acidified food emulsions treated with high pressure

The stability and rheology of acidified model oil-in-water emulsions (pH 3.6 +/- 0.1) were evaluated before and after high-pressure treatments. Varying concentrations of canola oil (0-50% w/w), whey protein isolate, polysorbate 60, soy lecithin (0.1-1.5% w/w each), and xanthan (0.0-0.2% w/w) were chosen. Exposure to high pressures (up to 800 MPa for 5 min at 30 degrees C) did not significantly affect the equivalent surface mean diameter D[3,2], flow behavior, and viscoelasticity of the whey protein isolate and polysorbate 60-stabilized emulsions. Pressure treatments had negligible effects on emulsion stability in these systems, except when xanthan (0.2% w/w) was present in which pressure improved the stability of polysorbate 60-stabilized emulsions. Soy lecithin-stabilized emulsions had larger mean particles sizes and lower emulsion volume indices than the others, indicating potential instability, and application of pressure further destabilized these emulsions.     

Isolation of useful variants in alloplasmic crop brassicas in the cytoplasmic background of Erucastrum gallicum

Alloplasmic Brassica juncea was synthesized by repeatedly backcrossing amphidiploid of Erucastrum gallicum × B. juncea with pollen of B. juncea. The E. gallicum cytoplasm was also transferred to B. napus and B. carinata through alloplasmic (E. gallicum) B. juncea. RFLP analyses of organelle DNA confirmed the presence of E. gallicum cytoplasm in all the alloplasmics. The cytoplasm of E. gallicum, though alien, did not induce stable cytoplasmic male sterility in any of the oilseed brassicas. Many useful variants such as early flowering and dwarf phenotypes were isolated in the alloplasmics of B. napus and B. carinata. These morphotypes provide useful genetic variability for the improvement of crop brassicas. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genotypic differences in shoot silicon concentration and the impact on grain arsenic concentration in rice

Silicon in rice (Oryza sativa L.) has been demonstrated to be involved in resistance to lodging, drought, and salinity, and also enhances resistance to pests and diseases. The aim of this study was to determine the range of silicon concentration in a set of rice (Oryza sativa L.) accessions, and to determine if the natural variation of shoot silicon is linked to the previously identified silicon transporters (Lsi genes). Silicon concentration was determined in 50 field‐grown accessions, representing all sub‐populations of rice, with all accessions being genotyped with 700K SNPs. SNPs within 10 kb of the Lsi genes were examined to determine if any were significantly linked with the phenotypic variation. An XRF method of silicon determination compared favourably with digestion and colorimetric analysis. There were significant genotypic differences in shoot silicon ranging from 16.5 to 42.4 mg g^?1 of plant dry weight, but there was no significant difference between the rice sub‐populations. Plants with different alleles for SNPs representing Lsi2 and Lsi3 were significantly different for shoot silicon concentration. Shoot silicon correlated negatively with grain arsenic in the tropical and temperate japonica sub‐population, suggesting that accessions with high shoot silicon have reduced grain arsenic. This study indicates that alleles for Lsi genes are excellent candidate genes for further study to explain the natural variation of shoot silicon in rice.     

Inheritance and mapping of resistance against Cowpea mild mottle virus strain D1 in soybean

Cowpea mild mottle virus (CPMMV) is an emerging severe disease of soybean. The resistant genotypes, DS 12‐5 and SL958, were crossed with susceptible genotypes F4C7‐32 and JS335, respectively. Resistance reactions of sap‐inoculated F₂ plants and individual F₂ plant‐derived F₃ families indicated that resistance was controlled by a single dominant gene. Molecular mapping with bulked segregant analysis showed that Satt635 and UO8405 are linked to resistance gene which is located on linkage group H.     

水稻Wx复等位基因的鉴定及单片段代换系的建立

 利用微卫星标记“484/485”和“484/W2R”结合AccⅠ酶切对278份来自国内外水稻品种（系）进行了Wx座位复等位基因分析，共检测到15种等位基因，其中(CT)12-G、(CT)15-G、(CT)16-G、(CT)17-G、(CT)18-G、(CT)21-G为新发现的等位基因。以含不同Wx等位基因的20个品种（系）为供体亲本，利用回交和微卫星标记辅助选择相结合的方法，建立了72个以Wx等位基因为 (CT)11-G 的“华粳籼74”为受体的Wx复等位基因单片段代换系。这些单片段代换系共包含12种Wx等位基因，其代换片段长度最短为2.2 cM，最长为77.3 cM，平均为17.4 cM。