NH3 Volatilization from Urea-NBPT in Eucalyptus

High losses of nitrogen (N) by volatilization of ammonia from urea applied in Eucalyptus are expected due to the influence of plant residues on the soil surface. The study evaluated the N losses by volatilization of ammonia from urea coated with Thiophosphate N-(n-butil) triamide (NBPT) applied in soil with eucalyptus residues in surface under moisture treatments: fertilization in dry soil without irrigation; fertilization in dry soil with posterior irrigation depth (3 mm); fertilization in moist soil without irrigation and fertilization in moist soil with irrigation depth (3 mm). NBPT is a potential inhibitor of urease. Urea with NBPT shows lower losses by volatilization of ammonia when it is applied in dry soil; however in soil conditions of high moisture the losses as well as inhibitor effect of the NBPT are lower. The inhibitor effect of NBPT is reduced over time when it is subjected to moisture conditions.     

First Documentation of Male Sexual Maturation in Captivity of Pacific Goliath Grouper,Epinephelus quinquefasciatus

This is the first documentation of male sexual maturation in captivity of Pacific goliath grouper. Males weighed between 15.3 and 16.6 kg and measured 93.5 and 97 cm in total length. No mature females were found during the same 4-year period of observation in captivity.     

First report of an insect pest on Passiflora tenuifila Killip (Passifloraceae)

The genus Passiflora L. has more than 400 species, most of which occur natively in tropical and subtropical regions of South America. The fruit of Passiflora tenuifila Killip, one of the native species of Brazil, has great potential for commercial use by pharmaceutical and cosmetic industries, due to its high content of phenolic compounds, which are natural antioxidants. The study was conducted in two areas located in Tocantins and in the Federal District, Brazil. The presence of globose lumps and thickening of the stems on plants of Pa. tenuifila was observed on plants in these areas. Injured samples taken from both locations were analyzed and showed the presence of larvae and pupae of a Curculionidae, which completed their life cycle in the laboratory. The adults were identified as Philonis crucifer (Brèthes) (Coleoptera: Curculionidae). In Tocantins, 100% of the plants in the trial area were infested, while in the Federal District trial the incidence of infestation was 20.3%. This is the first report of an insect on Pa. tenuifila, indicating the need to develop management strategies for this pest to be applied in commercial crops of this Passiflora species.     

Root proliferation in native perennial grasses of arid Patagonia,Argentina

Pappophorum vaginatum is the most abundant C4perennial grass desirable to livestock in rangelands of northeastern Patagonia,Argentina.We hypothesized that(1)defoliation reduce net primary productivity,and root length density and weight in the native species,and(2)root net primary productivity,and root length density and weight,are greater in P.vaginatum than in the other,less desirable,native species(i.e.,Aristida spegazzinii,A.subulata and Sporobolus cryptandrus).Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons.Root proliferation was measured using the cylinder method.Cylindrical,iron structures,wrapped up using nylon mesh,were buried diagonally from the periphery to the center on individual plants.These structures,initially filled with soil without any organic residue,were dug up from the soil on 25April 2008,after two successive defoliations in mid-spring 2007.During the second growing season(2008–2009),cylinders were destructively harvested on 4 April 2009,after one or two defoliations in midand/or late-spring,respectively.Roots grown into the cylinders were obtained after washing the soil manually.Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice,which supported the first hypothesis.The greater root net primary productivity,root length density and weight in P.vaginatum than in the other native species,in support of the second hypothesis,could help to explain its greater abundance in rangelands of Argentina.     

A multiplex microsatellite tool for conservation genetics of the endemic limpet Patella candei in the Macaronesian archipelagos

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Rubrivivax gelatinosus biomass as an immunostimulant for pacu Piaractus mesopotamicus

Rubrivivax gelatinosus is a bacterium present in the environment successfully used for treatment of fish industry effluent. Besides cleaning the effluent, this bacterium provides a biomass rich in proteins and carotenoid as a metabolic product. This study describes for the first time the use of this biomass as an immunostimulant feed. Haematological, immunological, biochemical and growth parameters in pacu Piaractus mesopotamicus fed control diet or diets supplemented with 0.5 or 1.5 g kg^?1 of the R. gelatinosus biomass during 60 days were assessed. Fish were sampled at 0, 30 and 60 days. The inclusion of increasing levels of biomass in feed increased thrombocytes and neutrophils (P < 0.05) and decreased lymphocytes (P < 0.05) as well as activated the complement system (P < 0.05). Glucose levels, hepatosomatic index and weight were positively affected by the inclusion of R. gelatinosus biomass (P < 0.05). The use of R. gelatinosus biomass in feed improved the immune response of fish through the enhancement of some phagocytic cells, reduced time to activation of the complement system and increased growth parameters. This study reveals a promising use for a by‐product resulted in the wastewater treating in aquaculture.     

Dietary bee pollen affects hepatic–intestinal histomorphometry of Nile tilapia fingerlings

The bee pollen is considered an excellent source of flavonoids, carotenoids, phenolic compounds, sterols and minerals; and possesses the ability to boost the immune system, antioxidant action and other interesting therapeutic effects. This study was carried out aiming to evaluate the inclusion of bee pollen in extruded commercial diets of Nile tilapia fingerlings and its effects on the hepatic‐intestinal histomorphometry and zootechnical performance. A total of 225 tilapia fingerlings (1.25 ± 0.05 g) were distributed in a completely randomized design in 15 tanks (30 L) maintained in a recirculation water system with three treatments (0% or control, 1.5% and 2.5% of bee pollen inclusion) and five replicates. Feeding rates were defined from the weekly biometrics and periodic monitoring of the physical–chemical water quality parameters. The water quality variables remained within the appropriate range for the species throughout the experiment. There was no significant difference for the somatic indexes and zootechnical parameters in this experiment. However, the inclusion of bee pollen in Nile tilapia fingerlings diets showed a linear increase in hepatocyte morphology (p = .0098). For the intestinal variables of villus height a significant linear increase was observed (p < .05) as the pollen inclusion increased. In fish that received 2.5%, the number of goblet cells was significantly higher (p < .001) than control group and 1.5%. In this sense, the inclusion up to 2.5% bee pollen in extruded commercial diets of Nile tilapia fingerlings had a positive impact on hepato‐intestinal histomorphometry without causing negative effects on the zootechnical performance.     

Leaf gas exchange and fruit yield in sweet orange trees as affected by citrus variegated chlorosis and environmental conditions

Citrus variegated chlorosis (CVC) is a disease caused by the bacterium Xylella fastidiosa. The most productive areas for citrus in Brazil are the northwestern and the northern regions of the São Paulo state, where CVC incidence is more severe. Additionally, these areas have the highest temperatures as well as significant vapor pressure deficits (VPD) and seasonal droughts. Environmental stresses are known to affect CVC-infected plants under semi-controlled conditions, but it is unclear whether similar effects occur in the field. The objective of this work was to evaluate the CVC leaf symptoms and environmental influences on fruit yield and size, and physiological parameters of healthy and CVC-affected plants (including both non-symptomatic and symptomatic leaves) in the morning and afternoon during the wet and dry seasons of 2003 in the southern, central and northern regions of the São Paulo state, Brazil. Increased VPD caused the stomatal conductance (gs) and CO₂ assimilation rates (A) to drop in healthy plants, but diseased plants had low VPD influences on gs, especially closer to the northern region and in leaves that were more symptomatic, confirming that diseased plants do not respond to changes in environmental VPD, corroborating several results reported in the literature. Although symptomatic northern leaves exhibited low stomatal apertures, the northern region had the highest air temperatures and VPDs, increasing the water loss in these plants, suggesting that towards the northern region plants face greater atmospheric and soil water stress. The fruit size of diseased plants diminished towards the north, while the fruit size of healthy plants must have been influenced by the tree fruit load. We suggest that CVC-affected plants suffer greater physiological damage if grown under environmental constraint, such as that found in the northern region of the São Paulo state.     

Human disturbance affects enzyme activity,microbial biomass and organic carbon in tropical dry sub-humid pasture and forest soils

ABSTRACT

The Brazilian dry forest occupies an area of about 1 million km² approximately 46% of which has been deforested. Many studies have been done on the effects of this on productivity and soil chemical attributes. However, little is known about soil enzymatic activity, which is sensitive to environmental changes. The objective of this study was to evaluate the effects of deforestation using different levels of human disturbance on soil enzyme activities, organic carbon content, microbial biomass, and microbial community. We studied areas covered with forest (TDF), old grass (OG), or new grass (NG). Soils from NG had increased microorganisms, which restored important processes related to carbon, sulfur, and nitrogen cycling, so that they resembled those in the forested area. The results of this study showed that the conversion of forest to pasture with a high level of human disturbance could decrease the activities of β-glucosidase, urease, alkaline phosphatase, and fluorescein diacetate in the soil by up to 87%, 66%, 62%, and 58%, respectively. These findings suggest that human disturbance can cause substantial changes in the enzymatic activity and microbial community in the soil. We suggest that maintaining grass pasture with low human disturbance should have fewer impacts on soil quality.