Salinity and nitrogen fertilization affecting the macronutrient content and yield of sweet pepper plants

The effects of salinity due to sodium chloride (NaCl) and nitrogen (N) concentration in the nutrient solution were studied with sweet pepper plants. Four saline treatments combined with two N fertilization were used. Nitrate‐nitrogen (NO₃ ^‐‐N) presence in the nutrient solution produced an increase of sodium (Na) and potassium (K) contents in leaves as well as N. Salinity promoted a reduction of K, phosphorus (P) and Ca and increased the Na concentration in leaves. Calcium (Ca) concentrations were lower in the higher NO₃ ^‐‐N treatment although N level was reached adding calcium nitrate and salinity increased P, K, Na, Ca, and magnesium (Mg) contents in fruits. Yield was increased in the highest N treatment.     

High efficiency genetic transformation of sour orange (Citrus aurantium) and production of transgenic trees containing the coat protein gene of citrus tristeza virus

In preliminary experiments on Agrobacterium-mediated transformation of citrus, we found transformation events occurring in callus formed from the cambium. Factors affecting Agrobacterium-sour orange (Citrus aurantium L.) interactions, such as culture medium, explant source and culture conditions, were studied to assess competence for transformation in such callus and to improve transformation frequency. Cell divisions and redifferentiation from the transgenic cells leading to transformation events were stimulated more by a combination of benzylaminopurine (BAP) + naphthalene-acetic acid (NAA) in the regeneration-selection medium than by BAP alone. Both age and source of the sour orange plant material affected transformation frequency. Explants from 4-month-old seedlings grown in the greenhouse showed higher transformation frequency than younger and older plant materials, indicating that they had a more suitable balance between dedifferentiated cells competent for transformation and Agrobacterium virulence. Enhancement of transformation frequency enabled us to incorporate the coat protein gene of citrus tristeza virus (CTV) in a sufficient number of sour orange plants to be able to evaluate this strategy for producing CTV-resistant plants.     

Particle Phase Concentrations of Polycyclic Aromatic Hydrocarbons in the Atmospheric Environment of Jinámar,Gran Canaria

Airborne concentrations of 8 polycyclic aromatic hydrocarbons (PAHs): fluoranthene, Flt, Pyrene, Pyr, benzo(a)anthracene, BaA, chrysene, Chr, benzo(b)fluoranthene + benzo(k)fluoranthene,B(b + k)F, benzo(a)pyrene, BaP and benzo(g,h,i)perylene, B(ghi)P,were measured in Jinámar, a small town on the island of Gran Canaria (Spain) during a 12 month period (January 1995–December 1995). Concentrations ranged between 0.613 ng m^-3 for B(ghi)P and 0.040 and 0.046 ng m^-3 for pyrene and chrysene. Except for BaA all PAHs occurred at lower concentrations at temperatures below 20 °C. Relative humidity seems to influence concentrations of pyrene, chrysene, benzo(b + k)fluoranthene and benzo(a)pyrene, also affecting the latter ina different way to the other three hydrocarbons cited.     

Influence of paclobutrazol and substrate on daily evapotranspiration of potted geranium

The application of plant growth regulators and the use of different culture media are common practices in potted ornamental crops. We report the results of a study to evaluate the effect of two substrates (peat moss or coconut fiber) and spraying 30 ppm paclobutrazol (PAC) on water resource management of zonal geranium (Pelargonium × hortorum L.H. Bailey) seedlings growing in a greenhouse during spring–summer. Growth, water consumption, leaching, evapotranspiration rate (ET), water use efficiency (WUE) and leaf water potential were determined. Plant growth was greater in peat moss (peat) than in coconut fiber (coconut), while the use of PAC decreased plant growth in both substrates, although more markedly in peat. Coconut produced a higher leaching fraction than peat in both PAC-treated plants and non-treated plants, although PAC application increased the leaching fraction in both substrates. Water consumption was lower in coconut than in peat and decreased in response to PAC. Peat was more effective at improving the water-use efficiency and increased the electrical conductivity in the leachate, while PAC decreased the latter in this same substrate. Daily ET showed a maximum of 200 mL/pot in peat and a minimum of 60 mL/pot in the coconut-PAC treatment. During the experimental period, accumulated ET values were higher in peat than in coconut, while the application of PAC reduced the value in peat but increased it in coconut. The evolution of ET per hour during the day showed that the highest rate (23 mL/h) was registered at midday in peat, while about 90% of ET occurred between 10 and 18 h in all treatments. When a cycle of water stress and recovery was applied, the peat induced the highest ET values of all treatments during the first days of drought, but the lowest ET after a week of drought. PAC modified this response, favoring a more balanced behavior of ET, although after the second cycle of drought this effect disappeared. Based on these results, the best strategy in normal irrigation conditions would be to use coconut fiber and not apply PAC, because this provides plants of excellent commercial quality with low water consumption. In plants at moderate water deficit PAC played a more important role than the substrate, improving the water status of plants with both substrates used. However, in the face of severe water stress the effect of PAC disappeared and peat acted as a better substrate than coconut fiber.     

Stress response and lipid composition in shrimp Litopenaeus vannamei fed diets enriched with squid or scallop viscera meal

We substituted 10% of fishmeal with scallop (Argopecten ventricosus) or squid (Dosidiscus gigas) by‐product meal in a feed for shrimp (Litopenaeus vannamei) growth assay that lasted 60 days and then shrimps were submitted to handling stress. Shrimp fed the control diet had smaller weight gain and lower recovery after stress. Prostaglandins in gills were affected by diet and stress, with significant differences in shrimp fed the control diet before and after the stress. Hydroperoxides were increased after stress, while isoprostanoids were higher in shrimp fed the control diet. The gene expression of Glutathione peroxidase and Catalase was increased on the stressed shrimp fed the scallop diet, with no differences among diets for Superoxide dismutase or Cyclooxygenase. Arachidonic acid in the phospholipid fraction of muscle was the only fatty acid affected by stress and diet. Cholesterol oxidation products were significantly higher in shrimp fed the scallop diet compared to shrimp fed the control diet before applying the stress. A PCA analysis grouped in one‐factor growth variables, as well as Superoxide dismutase, esterified astaxanthin and isoprostane, while another factor was determined by stress, prostaglandin and hydroperoxide levels in gills. The partial substitution of fishmeal with scallop of squid by‐product meals affected growth and stress differently, indicating shrimp that grew up more were not necessarily more tolerant to handling stress, which can have a strong repercussion in aquaculture, particularly during density control, recording of growth and harvest.     

Estimation of soil salinity in semi‐arid land using a geostatistical model

Soil salinity is one of the great problems in arid and semi‐arid environments. The estimation and prediction of spatial soil salinity may be considered as a stochastic process, observed at irregular locations in space. Environmental variables usually show spatial dependence among observations which is an important drawback to traditional statistical methods. Geostatistical techniques that analyse and describe the spatial dependence and quantify the scale and intensity of the spatial variation, provides spatial information for local estimation of soil salinity. In this paper we propose a Gaussian Spatial Linear Mixed Model (GSLMM), which involves a non‐parametric term, accounting for a deterministic trend given by exogenous variables, and a parametric component defining the purely spatial random variation, possibly due to latent spatial processes. We focus here on the analysis of the relationship between soil electrical conductivity as a parameter related directly to soil salinity as well as sodium content (sodicity) to identify spatial variations in these parameters. This kind of methodology is demonstrated as a useful tool for environmental land management. Copyright © 2007 John Wiley & Sons, Ltd.     

Carcase and component yields of rheas

1. Three Greater Rheas (Rhea americana) and 5 Lesser Rheas (Pterocnemia pennata) were slaughtered, using the procedures conventional for ostriches in Soudi Africa, in order to determine the expected yield of by‐products and saleable lean meat, fat and bone of rheas.

2. Differences (P< 0.05) between species were found in the proportional weight of the wings, feet, skin and liver. The wings, feet and head of rheas form a higher proportion of the carcase than in ostriches, whereas the skin of the former represents a lower percentage of body weight.

3. Lean meat production from rheas (64% on a carcase weight basis) is in the same order as for ostriches, broilers, turkeys and beef.     

Current Status and Bottle Neck of Octopod Aquaculture: The Case of American Species

The increasing market demand for cephalopods and the experiences obtained with different species has boosted the interest in developing their culture in Latin America. In 2008, an international workshop was held in Puerto Montt, Chile, with 14 experts in experimental cephalopods aquaculture from Brazil, Chile, Spain, and Mexico. Several topics were approached within the holobenthic species Octopus maya and the merobenthic species Enteroctopus megalocyathus, Octopus vulgaris, and Robsonella fontaniana. Part of the conclusions demonstrated that the two greatest difficulties for their production were survival of paralarvae for merobenthic species, and survival of early juveniles for holobenthic species. Besides, there is a need to study the endogenous and exogenous factors affecting health and nutritional status of embryos, paralarvae, and juveniles. These stages, which may limit the culture, should be extensively studied in order to develop the appropriate environmental conditions and culture systems for the physiological and behavioral requirements, from egg incubation up to juveniles to reach a grow‐out phase.