Freshwater catfish jundiá (Rhamdia quelen) larvae are prepared to digest inert feed at the exogenous feeding onset: physiological and histological assessments

This study assessed the morphological development of jundiá larvae’s digestive system and digestive proteolytic activity. Specific serine proteinases activities varied over time, with the highest peak at 12 h after hatching (AH), which corresponded to 296.38 ± 84.20 mU mg^?1 for trypsin and 315.45 ± 42.16 mU mg^?1 for chymotrypsin. Specific aspartic proteinases activities increased up to the start of weaning, oscillated during that phase, but showed a consistent increase after that, resulting in the highest specific activity at 252 h AH (7.88 ± 0.68 mU mg^?1). Gel assays showed different molecular forms, especially of serine proteinases. Histology showed the gastrointestinal tract development onset at 0 h AH and open mouth at 4 h AH. At 16 h AH, the following differentiation of the digestive tract was evident: oropharyngeal cavity, esophagus, liver, pancreas, stomach, and intestine. At 40 h AH, zymogen granules in the pancreas were observed, and at 48 h AH, mucus in the digestive tract and gastric glands in the stomach. Findings indicate that jundiá has a functional stomach before the end of vitelline reserves. Therefore, jundiá larvae are probably capable to digest inert feed at the exogenous feeding onset.     

Tree Adoption and Nursery and Propagation Practices in Smallholder Upland Farms in Inopacan and Isabel, Leyte, the Philippines

This paper examines seedling nursery and propagation practices in smallholder farms in two upland areas in Leyte in the Philippines. The case study areas are relatively remote, little forestry extension has been carried out, and traditional practices can be observed. These practices were examined through a survey of smallholders and observation of forestry activities. It was found that in spite of various constraints and notably the lack of planting materials, farmers are interested in forestry and are adopting some naturally growing trees and producing their own seedlings. To make way to their crops, farmers have removed some naturally growing trees of some particular species on their farms. For the purpose of introducing trees to farms, wildlings are widely used as planting material. Some farmers also collect seeds and treat them in preparation for planting, using methods which differ from those recommended elsewhere by extension agencies, but which are nevertheless highly effective.     

Nutrition of fig (Ficus carica L.) under hydroponics and greenhouse conditions

In this investigation the extraction curve of macronutrients (N, P, K, Ca, Mg) and micronutrients (Fe, Cu, Zn and Mn) were determined in the cultivation of fig. A system of intensive production of fig in greenhouse and hydroponics was established with 1.25 plants m^?2. The determination of the nitrogen content was done by the micro-Kjeldahl method. The P was by the yellow molybdovanadate method throughon a spectrophotometer. The K was determined by flamometry and the Ca, Mg, Fe, Cu, Zn and Mn were determined by atomic absorption spectrophotometry. Of the organs analyzed, the stem was the that accumulated more dry matter, then, the leaves and finally the fruits. The nutrient extraction dynamics presented similar upward behavior in all nutrients. The demand for macronutrients in decreasing order was N?>?K?>?P?>?Ca?>?Mg and for the micronutrients Cu?>?Fe?>?Mn?>?Zn.     

Responses of coppiced Eucalyptus to macro- and micronutrient application

Coppicing is a widely adopted management system for forest plantations; however, little information is available pertaining to responses to fertilizer application. Our objective was therefore to assess the effect of individual and conjunct omissions of N, P, K, Ca, Mg, B, and Cu on the growth of a highly productive Eucalyptus urophylla?×?E. grandis hybrid clone, managed for coppicing at the second rotation, in two soils of contrasting fertility in southeastern Brazil. Two commercial sites of approximately 7 years of age, one in an Arenosol and the other in a Ferralsol, were harvested and the experiments installed. At the Arenosol site, the yield from the fertilizer treatment in the coppice system (R2) was the same as determined for the first rotation (high forest; R1), at approximately 40 m³ ha^?1 year^?1 at 6 years old. In contrast, the yield from the fertilizer treatment in R2 at the Ferralsol site was 11% lower compared with R1. Despite some alterations in leaf nutrient concentrations, other than for K at the Arenosol site (where the K omission treatment reduced wood volume at 6 years by 21%), no yield reduction was found for any no-fertilizer treatments. Due to the widely distributed root system already established in coppiced plantations, ensuring a large volume of soil exploration, coppiced eucalypts only responded to K application. This is due to low soil K availability and the high K demand in eucalypt plantations.

     

Native leguminous plants for mineland revegetation in the eastern Amazon: seed characteristics and germination

New Forests - For the effective use of native plants for mineland revegetation, an understanding of seed dormancy break and germination requirements, and seed storage tolerance is indispensable. In...     

Selecting appropriate faba bean var. minor varieties for production under Northern European environmental conditions

The aim of the experiments was to evaluate a selection of faba bean (Vicia faba L.) var. minor varieties for further production improvement on the basis of their productivity and phenotype characteristics under the short season of the Northern European environmental conditions. The varieties evaluated were: Bauska, Favel, Fuego, Gloria, Jõgeva, Lielplatones, Priekulu and Priekulu viettejas. The highest and most stable average yield for 2015–2016 years was recorded in Bauska and Priekulu, with 3.77 and 3.64?t/ha, respectively. The incidence of chocolate spot and rust was in low to middling. Plant average height for 2015–2016 years was greatest in Bauska, Lielplatones and Priekulu vietejas, with 107.4, 110.7 and 110.0?cm, respectively. Resistance to lodging was best in Bauska and Fuego. From these yield and phenotype characteristics results we conclude that Lielplatones is the most suitable faba bean var. minor varieties for breeding in Northern European conditions, because of the following characteristics: middle yielding, quite high content of protein, very small seeds, low susceptibility to chocolate spot, good resistance to lodging. Thus almost every tested variety had some very good characteristics, which may also be valuable for the breeding of new varieties.     

Chemical Composition and Antioxidant Activity of the Main Fruits,Tubers and Legumes Traditionally Consumed in the Andean Regions of Ecuador as a Source of Health-Promoting Compounds

Plant Foods for Human Nutrition - Thirteen fruits, eight legumes and three tubers consumed in the Andean regions of Ecuador were studied to determine their bioactive compounds, organic acids,...     

High?throughput phenotyping of two plant?size traits of Eucalyptus species using neural networks

In forest modeling to estimate the volume of wood, artificial intelligence has been shown to be quite effi-cient, especially using artificial neural networks (A...     

Field evaluation of systemic imidacloprid for the management of avocado thrips and avocado lace bug in California avocado groves

BACKGROUND: The efficacy of systemic applications of imidacloprid for the management of avocado thrips and avocado lace bug was determined in field trials. Following insecticide treatment by chemigation, leaves of appropriate age for each insect were sampled over a 6 month period and used for bioassays. Imidacloprid residues were measured by ELISA in leaves used for bioassays to determine concentrations of insecticide that were toxic to both pests. RESULTS: The uptake of imidacloprid into treated trees was extremely slow, peaking in the current year's leaf flush at only 8 ng cm^?2 leaf tissue after 15 weeks. Avocado thrips mortality in bioassays with young flush leaves, the preferred feeding substrate for this insect, was minimal, indicating that imidacloprid concentrations were below threshold levels needed for effective control. Residues present in older leaves, which are preferred by the avocado lace bug, were higher than in young flush leaves, and provided good control of this pest. Probit analysis of bioassay data showed that the avocado lace bug (LC₅₀ = 6.1 ng imidacloprid cm^?2 leaf tissue) was more susceptible to imidacloprid than the avocado thrips (LC₅₀ = 73 ng imidacloprid cm^?2 leaf tissue). CONCLUSIONS: In spite of the slow uptake of imidacloprid into avocado trees, the levels of imidacloprid would be sufficient to control avocado lace bug infestations. In contrast, the slow uptake would be problematic for avocado thrips control because inadequate levels of insecticide accumulate in new flush foliage and would allow avocado thrips populations to build to levels that would subsequently damage developing avocado fruit. Copyright © 2010 Society of Chemical Industry