Influence of phosphorus fertilization on the response of pinus genotypes to glyphosate subdoses

New Forests - Previous studies have reported that phosphorus transporters are involved in glyphosate uptake by plants, so phosphorus fertilization might act as an attenuator of glyphosate effects...     

Carbon dynamics in small tropical catchments under preserved forest and cacao agroforestry systems

Agroforestry Systems - Inland waters such as streams that receive carbon from terrestrial landscapes usually have a net heterotrophic metabolism and emit significant amounts of CO2 to the...     

Effects of extrusion processing on digestibility of peas, lupins, canola meal and soybean meal in silver perch Bidyanus bidyanus (Mitchell) diets

Two experiments were conducted to investigate effects of processing on apparent digestibility coefficients (ADCs) of legumes and oilseeds for juvenile silver perch, Bidyanus bidyanus (～49 g). The first experiment evaluated interactive effects of ingredients (lupins or field peas), processing (whole seed; hulls on or hulls off) and extrusion cooking (raw or extruded) on ADCs for juvenile silver perch (～4 g fish^?1). The second experiment was a three‐fixed‐factor anova designed to evaluate interactive effects of ingredients (soybean meal or canola meal), extrusion cooking (raw or extruded) and inclusion content (30% or 50% of the diet) on ADCs for juvenile silver perch (～4 g fish^?1). Lupin protein was more digestible than that of peas (ADC for crude protein 91% vs. 85% for peas) but the organic matter was less digestible (ADC for organic matter 50% vs. 67% for peas). Dehulling lupins significantly improved ADCs for all indices (dry matter, organic matter, energy and crude protein), but extrusion had no effect because lupins do not contain starch or heat‐labile anti‐nutrients. Conversely, for starch‐rich peas that contain heat‐labile trypsin inhibitors, both dehulling and extrusion significantly improved ADCs. Digestibility of soybean meal was much higher than that of canola meal. For soybean meal, neither processing, content nor their interaction affected digestibility but extrusion improved ADCs for dry matter, organic matter and energy but there was an interaction with content. Although higher overall, digestibility for these indices declined with increasing content for extruded product while there were only minor effects of inclusion for raw product. Benefits of extrusion were attributed to reductions in anti‐nutrients, including phytic acid. For canola, there were no interactions between extrusion and content for any ADC. Increasing content reduced ADCs for crude protein, dry matter and organic matter but did not effect energy. Surprisingly, extrusion of canola also reduced digestibility for all ADCs. Dehulling improved both lupins and peas. Crude protein for all ingredients was well digested with ingredients ranked: lupins>soybean meal>peas>canola meal. Energy digestibility was best for soybean meal and worst for lupins. Extrusion greatly improved digestibility of peas and to a lesser extent soybean meal, gave no benefits to lupins and was detrimental for canola.     

Replacement of fishmeal in diets for Australian silver perch Bidyanus bidyanus (Mitchell). II. Effects of cooking on digestibility of a practical diet containing different starch products

Abstract The interactive effects of cooking and starch type on the dry matter, gross energy and protein digestibility of diets fed to fingerling silver perch were examined. Nine experimental diets were made: a reference diet either uncooked or cooked, six other diets comprising uncooked reference diet supplemented with 30% uncooked or cooked wheat, maize or potato starch and one diet comprising uncooked reference diet supplemented with 15% pregelatinized maize starch. Cooking involved autoclaving at 121 °C for 15 min. The indirect method was used to calculate apparent digestibility coefficients, and chromic oxide (1%) was used as the inert indicator. Both ingredient type and cooking influenced dry matter and gross energy digestibility of diets. All diets had significantly different digestibility coefficients in the following order (from most to least digestible): reference > wheat > maize > potato, for both dry matter and gross energy. Cooking significantly increased the apparent digestibility of diets for both dry matter and gross energy. There was no significant effect of ingredient or cooking or their interaction on protein digestibility. Dry matter and energy digestibility of the diet containing pregelatinized maize starch were significantly higher than for diets containing cooked or uncooked starch products. Ingredient digestibility followed the same trend as diet digestibility. The results from this study indicate that the successful use of starch in practical diets for silver perch is dependent on the origin and processing of the starch. The significant benefits of cooking in the reference diet suggest that pelleted diets should be cooked (e.g. steam conditioned or extruded).     

Carbohydrate utilization by juvenile silver perch, Bidyanus bidyanus (Mitchell). I. Uptake and clearance of monosaccharides following intraperitoneal injection

Abstract Intraperitoneal carbohydrate tolerance tests were done to assess the ability of silver perch, Bidyanus bidyanus, to utilize the predominant monosaccharides in plant ingredients currently being used in the formulation of aquaculture feeds for this species. Preliminary experiments carried out to assess baseline plasma glucose concentrations indicated that blood glucose levels were elevated within 2 min of handling and silver perch required a period of 48 h without feeding before plasma glucose levels remained constant. In the first carbohydrate test, either glucose, galactose or xylose were administered by injection into the intraperitoneal cavity at a dose rate of 1 g carbohydrate kg^?1 body weight (BW). In the second carbohydrate test, glucose was administered at a dose rate of either 2 or 4 g glucose kg BW^?1. Following injection, uptake and clearance rate of the carbohydrates from the blood stream was monitored over a 24‐h period. Silver perch were significantly more efficient at the uptake and clearance of glucose from the blood stream than xylose or galactose. Maximum plasma glucose concentrations (22.2 mmol L ^?1) were recorded at 1 h following injection and basal levels (3.44 mm ) were attained between 6 and 12 h following injection. For both galactose and xylose, maximum concentrations were recorded at 1 and 3 h, respectively, and concentrations of both monosaccharides remained significantly elevated 24 h after the administration. Plasma glucose concentrations of silver perch administered with either 2 or 4 g glucose kg BW^?1 were significantly elevated and peaked at similar levels (30.2 mmol L ^?1 and 30.7 mmol L ^?1 respectively) 3 h after injection. Basal plasma glucose concentrations were attained in silver perch injected with 2 g glucose kg BW^?1 at 24 h following administration. Plasma glucose concentrations remained significantly elevated in fish injected with 4 g glucose kg BW^?1 after 24 h. These findings indicate that silver perch are more efficient at utilizing glucose than either xylose or galactose, and that there are also differing maximum threshold for the inclusion of ingredients rich in glucose, galactose and xylose into the diets of silver perch.     

Assessment of induction and recovery times of anaesthesia in Astyanax bimaculatus using 2‐phenoxyethanol and the essential oils of Melaleuca alternifolia and Ocimum gratissimum

This study aimed to determine the lowest effective concentration (LEC) of 2‐phenoxyethanol (2‐Phe) and essential oils (EOs) of Melaleuca alternifolia and Ocimum gratissimum able to induce anaesthesia in Astyanax bimaculatus. LEC was assumed to be the required concentration to carry out anaesthesia in less than 3 min with recovery in <5 min and sufficient to carry out routine aquaculture procedures. The following concentrations were tested: 2‐Phe (100, 200, 300, 400, 500 and 600 µl/L); M. alternifolia (200, 300, 400, 500 and 600 µl/L); and O. gratissimum (10, 20, 30, 40, 50, 60, 70, 100, 150, 250 and 300 µl/L). Results show that all three agents evaluated have effective anaesthetic properties for use in Astyanax bimaculatus with LEC for 2‐Phe, M. alternifolia and O. gratissimum of 200, 300 and 60 µl/L respectively.     

Post-emergent herbicidal activity of cineole derivatives

Essential oils are being investigated as potential herbicides or to provide leads to new environmentally and socially acceptable herbicides. Novel hydroxy and ester derivatives of 1,8-cineole and 1,4-cineole were synthesised, by chemical and biological methods, and have shown pre-emergence herbicidal activity against annual ryegrass and radish. Effects on post-emergence activity of these derivatives, as well as 1,8-cineole, eucalyptus oil and the carboxylic acids from which the esters were derived, against annual ryegrass and radish, are reported here. Results suggest that reduced root and shoot growth observed in pre-emergence herbicidal bioassays were due to post-emergence activity rather than delayed germination. All tested substances had a dose-dependent, post-emergence herbicidal activity against annual ryegrass and radish with many derivatives showing improved activity relative to 1,8-cineole and high-cineole eucalyptus oil. However, results do not support the postulate that cineole esters would be more active than their respective carboxylic acid and the hydroxy cineole. Phytotoxicity of ester derivatives may be due to metabolic cleavage of the esters to the hydroxy cineole and carboxylic acid within the plant.     

Light and plant growth‐promoting rhizobacteria effects on Brachiaria brizantha growth and phenotypic plasticity to shade

This is the first report on the effect of light intensity and plant growth‐promoting rhizobacteria (PGPR) on the growth of a tropical forage grass, being a relevant study to improve pasture management in conventional farming and integrated crop‐livestock‐forestry systems. In this study, our aim was to evaluate the effects of light intensity and Burkholderia pyrrocinia and Pseudomonas fluorescens inoculation on Brachiaria brizantha cv. BRS Piatã growth, and phenotypic plasticity to shade. The experiment was conducted in a semi‐controlled environment. Seedlings of B. brizantha were allocated to full sun and shade. P. fluorescens and B. pyrrocinia were inoculated individually or co‐inoculated by soil drench, 14 days after seedling emergence. We evaluated morphogenesis, structural and growth parameters. Irrespective of the light regime, co‐inoculated plants had greater leaf area and SPAD index (chlorophyll content). Increase in total biomass production in co‐inoculated plants was over 100% and 300%, under full sun and shade respectively. Co‐inoculated P. fluorescens and B. pyrrocinia increased shade tolerance in B. brizantha, improving plant performance. Co‐inoculation promoted growth in B. brizantha under both sun and shade, indicating its potential as a bio‐fertilizer in conventional and integrated systems, especially in silvopastoral systems, where light availability to pasture growth may be limited.     

Effects of deficit irrigation strategies on cluster microclimate for improving fruit composition of Moscatel field-grown grapevines

The grapevine plays a very important role in the economic, social and cultural sectors of many regions; however vineyards are often grown in regions under stressful conditions and thus they are vulnerable to climate change. The objective of this research was to investigate the effect of partial root-zone drying (PRD) irrigation on vine water relations, vegetative growth, plant microclimate, berry composition and yield components, compared to conventional deficit irrigation (DI, 50% ETc), full irrigation (FI, 100% of ETc) and non-irrigated vines (NI). The study was undertaken in mature ‘Moscatel’ grapevines (Vitis vinifera L.) grown in Pegões, South of Portugal. Compared to the other irrigated treatments, PRD vines showed a better microclimate at the cluster zone with higher incident photosynthetic photon flux density (PPFD). Within the more open canopies of NI and PRD treatments, berry temperatures were higher than those of denser ones (DI and FI). Compared to the conventional irrigation technique the better microclimate observed in PRD vines was a consequence of a reduction in vine growth, where lower values of leaf layer number, leaf area, canopy wideness, water shoots and shoot weight were observed. In PRD vines we observed a tendency to a development of a deeper root system, while DI and FI showed a more homogeneous root distribution throughout the different soil layers. PRD showed an improvement in berry quality with higher values of flavour precursors, and total phenols concentration without any significant yield reduction compared to DI and FI.