Crop water use indicators to quantify the flexible phenology of quinoa (Chenopodium quinoa Willd.) in response to drought stress

Models can play an important role in agricultural planning and management. Thermal time accumulation is a common way of describing phenological development in crop models, but the sensitivity of this concept to water stress is rarely quantified. The effect of pre-anthesis droughts on the timing of anthesis and physiological maturity was assessed for quinoa (Chenopodium quinoa Willd.) var. ‘Santa Maria’, with the help of two field experiments (2005–2006 and 2006–2007) in the central Bolivian Altiplano. Various treatments with different sowing dates and irrigation applications were considered. To evaluate the effect of drought stress on crop development, drought stress during the first 60 days after sowing was assessed with three different stress indicators: the number of days that the soil water content of the root zone was above a threshold, the average relative transpiration, and the sum of daily actual transpiration, standardized for reference evapotranspiration (∑(T_a/ET₀)). The best indicator to quantify the effect of pre-anthesis drought stress on phenological development was ∑(T_a/ET₀) cumulated until 60 days after sowing. This indicator showed a significant logarithmic relation with the time to anthesis and time to physiological maturity. Correlations of the drought stress indicator with thermal time accumulation were better than with calendar time accumulation. Due to an effect of post-anthesis droughts, the correlations of the drought stress indicator with the time to anthesis were stronger than with the time to physiological maturity. It was also demonstrated that deficit irrigation can contribute to a better agricultural planning due to a better control of the phenological development of quinoa. The proposed relations can be used for modeling phenological development of quinoa in drought prone regions and for efficient deficit irrigation planning.     

Supplementation of organic acids and algae extracts in the diet of red drum Sciaenops ocellatus: immunological impacts

The evaluation of a wide variety of immunostimulatory compounds in the diet of cultured fish has received heightened attention in recent years. However, two organic acids, polyhydroxybutyrate (PHB) and potassium diformate (KDF), have been researched to only a limited extent with aquatic species but have been shown to have various positive effects on terrestrial animals. Two algae extracts, carrageenan and alginic acid, also have been shown to elicit immunostimulation in some fish. Therefore, this study was conducted with red drum, Sciaenops ocellatus, as a model marine species to study the effects of organic acids and algae extracts as feed supplements by evaluating several humoral and cellular immune responses. A 7‐week feeding trial was conducted with disease‐free juvenile red drum (average initial wt. 2.6 ± 0.2 g). Semipurified diets were formulated to be isocaloric and contain 40% crude protein. Based on previous studies with other fish species, experimental diets were produced by supplementing the basal diet with KDF at 0.6%, PHB at 2%, alginic acid at 1% or carrageenan at 0.5% by weight in place of cellulose. Fish were stocked into 110‐L aquaria operated as a recirculating system with each diet assigned to three replicate aquaria containing 15 fish. At the end of 7 weeks, weight gain and feed efficiency were significantly (P < 0.0001) reduced in fish feed PHB compared to the basal diet and both algae extracts. The greatest phagocytic activity was found in fish fed the diet containing PHB. Total immunoglobulin level was higher in fish fed the diet supplemented with carrageenan. Goblet cell proliferation was greatest in the posterior end of the gastrointestinal tract but not different among dietary treatments. Organic acids and algae extracts evaluated in this study produced variable immunological responses in red drum with carrageenan showing the greatest potential as an immunostimulant.     

Preliminary assessment of in vivo safety of potentially probiotic lactic acid bacteria for American bullfrog culture

The effect of the administration of beneficial lactic acid bacteria (LAB): Lactococcus lactis CRL 1584, L. lactis CRL 1827, Enterococcus gallinarum CRL 1826 and combined CRL 1584+ CRL 1826 on the development of bullfrog embryos from the hatching stage until 31 days (tadpole) was evaluated. In vitro assays indicated that 10³, 10⁶ and 10⁹ CFU mL^?1 single LAB strains remained viable until 24 h in 10% Ringer. Around 10⁹ CFU mL^?1 LAB (individually and combined) were used in an experimental design built to evaluate their effect when administrated at different intervals (three 7‐day cycles with 5‐day rest periods in between) to embryos until day 31. The highest potentially beneficial population (LAB) numbers were detected in the LAB‐treated groups. All the LAB‐treatments increased it and were significantly higher than the controls. Although the highest, potentially pathogenic, population (Red‐Leg Syndrome‐RLS‐related pathogens) numbers were detected in the control and the lowest in the CRL 1584+ CRL 1826‐treated group, they did not differ significantly. Stereoscopic studies showed no malformations in any LAB‐treated group and all the specimens reached the same stage of their biological cycle with a survival >94%. The histological structure of target organs for RLS‐associated pathogens (intestine and skin) and stomach was not affected and the spleen was developed. Only the LAB‐treated groups showed microorganisms associated with the intestinal mucus, without inflammatory reaction in the lamina propria. This is the first report on the evaluation of the absence of adverse effects after LAB administration to bullfrog embryos using indigenous microorganisms.     

Gar biology and culture: status and prospects

Many lepisosteid populations in North America have declined and many are now threatened as a consequence of habitat loss and alteration and commercial and sport overfishing. Over the last two decades, morphological, histological and molecular studies allowed distinguishing between different phases of development and the nutritional condition of larvae. Ontogeny of the digestive enzymes of gar larvae indicated the possibility to feed them artificial feeds since early developmental stages. An in vitro digestibility system to test different feed ingredients has been used. Important characteristics of artificial diets were identified through different feeding experiments. Endocrinological studies showed the feasibility of altering larval development and the digestive capacity of larvae. Cloning of gar growth hormone opened new avenues to enhance growth in the gars. Plasmatic vitellogenin was isolated and purified, to develop a competitive enzyme‐linked immunosorbent assay, which allowed the straightforward separation of males from females to establish appropriate proportions for reproduction and also was used to evaluate hormonal protocols to induce gonad recrudescence and spawning. This review analyzes the biology, ecology and physiology of different gar species as a basis for their domestication, mass production of larvae for repopulation experiments and for the culture of commercial‐size gar.     

Validation of Molecular Markers and Haplotype Diversity at the SalTol Locus on Chromosome 1 of Rice

Rice （Oryza sativa L.） is the most important economic activity on earth as it is second largest single use of the land for food production and also consumed by the half of the world＇s population. Salinity is the one of the most common abiotic problem in rice growing areas of the world. Millions of hectares in the tropics, arid and semi arid region could be potential rice growing areas but either left idle or cropped with very low yielding varieties due to the lack of suitable salt tolerant high yielding modem varieties.     

Determination of methomyl in rape seeds,oils and meals

Methomyl added to rape seeds, oils or meals was detected by a thin-layer chromatographic-enzyme inhibition technique. The limit of detection in the presence of oil or meal extractive was 20 mg or 0.01 mg/kg. The amounts of methomyl recovered from oils and meals fortified at 0.01 to 20 mg/kg were comparable to the standard. When stored at 4 °C, methomyl in oil or meals, or in chloroform extracts, was stable for at least 10 and 21 days, respectively. No degradation was observed when methomyl was heated in ethanol at 72 °C for 2 h. Methomyl and its oxime were also detected with either iodo- or chloroplatinate reagent after t.l.c. The detection limits were approximately 600 mg for methomyl and 190 for the oxime.     

Pesticide action: Different response of erythrocyte membrane acetylcholinesterase to inhibition by organophosphorus compounds under varied dietary conditions

The inhibitory effect of malathion in conjunction with maloxon or other derivatives on the activity of rat erythrocyte membrane-bound acetylcholinesterase has been investigated after feeding diets known to affect the lipid composition of the membrane. The inhibition of AchE by preincubation of membrane preparations with this organophosphorus compound, possibly with contaminants, differed with the diet: the curve was sigmoidal after supplementation with corn oil and hyperbolic after supplementation with lard. In the latter case the kinetics of the inhibition became sigmoidal by assaying in the presence of cortisol or isoproterenol or by previous solubilization of the enzyme. These results indicate that some organophosphorus compounds can differentiate conformational states of acetylcholinesterase present in the erythrocyte membrane.