Alleviation of nickel toxicity and an improvement in zinc bioavailability in sunflower seed with chitosan and biochar application in pH adjusted nickel contaminated soil

This study demonstrates the reduction of nickel (Ni) toxicity and enhancing zinc (Zn) bioavailability from sunflower seed with biochar (BC) and chitosan (CH) application to Ni contaminated soil. The pH of experiment soil was adjusted to value 6.5 prior to its use in a greenhouse experiment. Acidified Ni contaminated soil was amended with Zn (4 mg kg^?1 soil), while BC and CH, both as alone [1% each (w/w)] and in combination [0.5% each (w/w)], were used as immobilizing agents for Ni. Significantly higher concentrations of Zn were found in seed receiving ZnSO₄ treatments. However, these results were more pronounced in the treatment (Zn+CH+BC) where Zn, CH, and BC were together applied. The Zn+CH+BC treatment improved seed quality parameters, phytate/minerals molar ratios, increased seed weight (per pot) up to 75%, Fe 41%, Zn 42% in seed, while reduced Ni concentration up to 17% in seed, over control. Similarly, Zn+CH+BC treatment significantly decreased oxidative stress by improving antioxidant defense system in sunflower. The results of this preliminary study suggest that further studies are obligatory to corroborate the extent of Ni immobilization in soil and enhancing Zn bioavailability from sunflower seed under field conditions with realistic and applicable rates of BC and CH.     

Screening of Yardlong bean (Vigna unguiculata (L.) Walp.ssp. unguiculata cv.-gr. sesquipedalis) genotypes for seed,yield and disease resistance traits

Genetic Resources and Crop Evolution - Yardlong bean genotypes have wide variability in seed coat colours. This study sought to screen of yardlong bean genotypes based on seed coat colour,...     

Wise selection of an indicator for monitoring the success of management actions

Objective approaches are needed to select species for monitoring management effectiveness and to justify conservation investments. We develop and apply two approaches for selecting the most cost-effective and informative indicator species with a case study of monitoring investments in invasive predator control in south-western Australia. We compared species selected by a qualitative approach involving experts scoring 17 criteria for 12 potential indicators to a quantitative metric based on empirical data for a subset of criteria. Both approaches accounted for the monitoring cost, potential for leverage, data uncertainty and the risk of choosing an un-representative or un-informative indicator, albeit in different ways. The indicator species selected by the quantitative metric was the western brushtail possum Trichosurus vulpecula – a relatively common medium-sized mammal in the study region. When costs were not considered explicitly in the qualitative approach, the indicator selected was the woylie Bettongia penicillata. When costs were sensibly incorporated in the qualitative approach, indicator rankings changed and the top-ranked species was again T. vulpecula. Although when costs were included the qualitative expert-driven approach delivered the same result as the quantitative metric, it was not robust to minor data adjustments, and incorporating expert uncertainty made it difficult to distinguish the value of potential indicator species from each other. The quantitative metric was comparatively robust to minor data adjustments, and enabled evaluation of data uncertainty in a transparent way, presenting a more objective approach that enables explicit selection of the most informative indicator for monitoring management actions.     

Investigation of mortality in Pacific oysters associated with Ostreid herpesvirus-1 μVar in the Republic of Ireland in 2009

High levels of mortality in Pacific oysters Crassostrea gigas in the Republic of Ireland were recorded during the summer of 2009. The new variant of Ostreid herpes 1 (OsHV-1 μVar) which first emerged in France in 2008 was identified from affected stocks. Retrospective data was collected from 70 oyster farmers through an interviewer-administered questionnaire to investigate the distribution and determinants of the mortality. Based on farmer recall, data were recorded at the batch level for cumulative mortality during 2009, start dates and duration of the mortality event and the age of animals affected. Observable mortalities were recorded in 109 out of 346 batches at 47 sites; 104 of the 109 batches were located in bays where OsHV-1 μVar had been detected. The records from bays where OsHV-1 μVar had been detected were analysed to characterize the pattern of mortality and potential risk factors. Batch mortality averaged 37% (18-65% quartiles) but showed a bimodal distribution (half the batches had mortality less than 45%). Mortalities started at the end of May and continued until early August, peaking in early July. On average oysters died over a period of 18 days. Mortality varied considerably both between and within bays. Mortality started in recently introduced batches and occurred later in the summer in established oysters, which is consistent with the introduction of an infectious agent. Mortality was significantly lower in adults compared with other age groups, which supports observations from France. Three variables were significantly (P<0.05) associated, in both bivariate screening and a logistic regression, with high batch-level mortality (>40%): oysters (i) introduced as juveniles, (ii) during or since the winter of 2008/9 and (iii) which spent less than 8h out of water (in a tidal cycle) (compared with oysters introduced as adults before the winter of 2008/9 and spending more than 8h out of water). Twenty-one percent of triploid batches experienced "high" (>40%) mortality compared with 10% for diploid batches which was significant (P<0.05) in the initial bivariate screening but not in the final logistic regression model. Future studies should develop improved methods to assess oyster mortality and follow stocks over time to better determine the influence of management and environmental factors on mortality.     

Evaluation of Salt Tolerance and Its Relationship with Carbon Isotope Discrimination and Physiological Parameters of Barley Genotypes

Soil management through the cultivation of salt-tolerant plants is a practical approach to combat soil salinization. In this study, salt tolerance of 35 barley (Hordeum vulgare L.) genotypes was tested at four salinity levels (0, 100, 200, and 300 mM NaCl in Hoagland nutrient solution) at two growth stages (germination and vegetative). The relationship between salinity tolerance and carbon isotope discrimination (CID) was also accessed. Results of the study carried out under laboratory conditions showed that a negative linear relationship was observed between salt concentration and germination as well as other growth parameters. Some genotypes showed good salt tolerance at germination but failed to survive at seedling stage. However, five genotypes, namely, Jau-83, Pk-30109, Pk-30118, 57/2D, and Akermanns Bavaria showed better tolerance to salinity (200 mM) both at germination and at vegetative growth stage. The salt tolerance of these barley genotypes was significantly correlated with minimum decrease in K⁺:Na⁺ ratio in plant tissue with increase in the root zone salinity. However, the case was reversed in sensitive genotypes. CID was decreased linearly with increase in root zone salinity. However, salt-tolerant genotypes maintained their turgor by osmotic adjustment and by minimum increase in diffusive resistance and showed minimum reduction in CID (Δ) with gradual increase in rooting medium salt concentration. Results suggested that the tolerant genotypes make osmotic adjustments by selective uptake of K⁺ and by maintaining a higher K⁺:Na⁺ ratio in leaves. Moreover, CID technique can also be good criteria for screening of salt-tolerant germplasm.     

Functional properties of protein isolates extracted from stabilized rice bran by microwave, dry heat, and parboiling

Protein isolates extracted from differently stabilized rice bran were analyzed to work out the food use potential. Bulk density remained higher for isolates obtained from heat stabilized bran, the treatments were found to have positive impact on the oil absorption properties, while the water absorption was slightly impaired owing to some possible configurational changes. Surface hydrophobicity and emulsion properties were improved with bran stabilization. Isolates exhibited better foaming properties owing to the flexible nature of protein molecules, with less intensive disulfide bonding, that were slightly affected by the stabilization treatment. Nitrogen solubility index followed a curved pattern with the least value near isoelectric point that showed an increasing trend toward basic pH, and parboiled protein isolates exhibited better gelling properties among the isolates.     

Effects of calcium availability on growth of larval Lake Sturgeon

A variety of environmental factors are known to influence growth rate and survival of larval fish. The effects of water chemistry, such as calcium hardness of freshwater systems, have been reasonably well‐described in teleosts in the early life stages. However, the Lake Sturgeon, Acipenser fulvescens, is unusual in the conjunction of high calcium demand for growth in early life (as in all vertebrate animals), but low internal calcium reserves due to relatively few bony structures, especially in early life. This study reared Lake Sturgeon from hatch until after first feeding in 0.1, 0.2 and 1.5 mM [Ca²⁺]. No differences were observed between rearing environments in hatching success or survival. Fish reared in the lowest [Ca²⁺] demonstrated earlier significant increases in wet weight and total length, and absorbed yolk at a faster rate. Fish in all treatments accumulated Na⁺ and Cl^? throughout the pre‐feeding stages and continued to increase whole‐body [NaCl] in the calcium‐limited water after feeding. Continued growth of fish in the lowest calcium concentration was significantly impacted as the fish grew, suggesting that water chemistry was an important influence on developmental progression, and therefore, factors relevant to long‐term survival such as condition and available time for feeding onset to occur.     

Exploring genetic diversity of lowland avocado (Persea americana Mill.) as a genetic reservoir for breeding

Genetic Resources and Crop Evolution - The avocado (Persea americana Mill.) is highly valued worldwide for its desirable nutritional properties and broader applications in the oil and...