Search results for "040103 agronomy & agriculture"
showing 10 items of 794 documents
Decoupling of light intensity effects on the growth and development of C3 and C4 weed species through sucrose supplementation
2002
Light availability has a profound effect on plant growth and development. One of the ways to study the effects of light intensity on plant growth and development without the confounding problem of photosynthate availability is sucrose injection/supplementation. A greenhouse experiment was conducted to evaluate the effects of light levels (0% and 75% shade) and sucrose injection (distilled water or 150 g sucrose l(-1)) on three weed species: redroot pigweed (Amaranthus retroflexus L., C4), lambsquarters (Chenopodium album L., C3) and velvetleaf (Abutilon theophrasti Medic., C3). The average total sucrose uptake was 7.6 and 5.9 g per plant for 0% and 75% shading, respectively, representing 47…
Mediterranean forage legumes grown alone or in mixture with annual ryegrass: biomass production, N2 fixation, and indices of intercrop efficiency
2016
Aims: To evaluate the productivity and N2 fixation of a range of Mediterranean forage legume species as well as their ability to be grown in mixture with a forage grass, and to verify whether N transfer occurs from the legume to the non-legume component of the mixtures and, if so, to what extent this process is affected by legume species. Methods: Seven legume species (Hedysarum coronarium L., Medicago scutellata L., Trifolium resupinatum L., Trifolium squarrosum L., Trigonella foenum-graecum L., Vicia sativa L., Vicia villosa Roth) were grown alone or in mixture with annual ryegrass (Lolium multiflorum L.). Biomass and N yields and biological N2 fixation (15N dilution technique) were measu…
Arbuscular mycorrhiza and fungal root endophytes of weeds in an altitudinal gradient in the Pamir Alai Mountains of Central Asia
2014
Arbuscular mycorrhiza and fungal root endophytes of three weeds, Galium tricornutum, Lycopsis orientalis and Scandix pecten-veneris, were studied in an altitudinal gradient of the Pamir Alai Mountains. Colonisation by arbuscular mycorrhizal fungi (AMF) was found in all species. Only in the case of G. tricornutum was there a rise in mycorrhizal parameters values found for the medium altitude range. Similar tendencies were observed in the case of the AMF colonisation potential assessment. This suggests that plant species' identity, dependency on symbiosis and interactions with soil properties determine root colonisation and the abundance of AMF in soils at the elevations in question. Four AMF…
Natural colorants improved the physicochemical and sensorial properties of frozen Brazilian sausage (linguiça) with reduced nitrite
2020
Made available in DSpace on 2021-06-25T12:18:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01. Added 1 bitstream(s) on 2021-07-15T15:05:51Z : No. of bitstreams: 1 S0103-90162021000300902.pdf: 246305 bytes, checksum: 130e2a2703383287ec0721e788c1b83e (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The use of natural colorants in meat products can keep its coloring attractive as well as meet the demand from consumers interested in products that are healthier. Nitrite is added as a preservative to these products and it is also a precursor of the generation of a specifically desired color in meat products. However, its use has been associated with the dev…
Long-term modelling of weed control strategies: analysis of threshold-based options for weed species with contrasted competitive abilities
2002
A simple life-cycle-based demography model was adapted for two contrasting weed species (Alopecurus myosuroides and Poa annual. This model included a seed production function that accounted for population self-regulation through weed:weed interactions. The A. myosuroides version of the model was tested with field data. Long-term simulations of population demography were then performed to investigate the relationship between weed control strategies based on density thresholds and both the frequency of herbicide use and the long-term economic profitability. This study confirms that threshold-based weed management strategies are more cost-effective than spraying every year and may allow import…
Effect of vernalization on the development and growth of Alopecurus myosuroides
2002
Alopecurus myosuroides is an annual winter grass weed present in many winter and spring crops. The vernalization responses of three populations of A. myosuroides were assessed using natural exposure during winter in two field experiments and using cold exposure of imbibed seeds in a refrigerator in two greenhouse experiments. It was observed that a period of chilling during the pregermination phase had a marked effect on subsequent phenology. In the greenhouse, the major effect of vernalization was the reduction in the vegetative period because of an early reproductive induction of the apex. Plant morphology was affected by vernalization via a decrease in biomass resulting from a reduced ti…
Effects of gellan-based coating application on litchi fruit quality traits
2018
The use of gellan-based coating formulation on litchi (Litchi chinensis Sonn. ‘Wai Chee’) fruit was investigated in order to determine its ability to improve color conservation and to maintain the overall quality. Fruits were treated with gellanbased coating (0.5% w/v) and glycerol (3% w/v) after dipping in ascorbic acid (1.5% w/v) and then stored at 5°C and 90% relative humidity for 15 days. Changes in peel color, soluble solid content, tritatable acidity, weight loss, antioxidant activity and phenolic content, were measured. Formulations containing gellan-based coating exhibited slightly improved water barrier properties and showed their active role in maintaining color characteristics an…
The use of soil electrical resistivity to monitor plant and soil water relationships in vineyards
2015
Abstract. Soil water availability deeply affects plant physiology. In viticulture it is considered as a major contributor to the "terroir" expression. The assessment of soil water in field conditions is a difficult task especially over large surfaces. New techniques, are therefore required to better explore variations of soil water content in space and time with low disturbance and with great precision. Electrical Resistivity Tomography (ERT) meets these requirements, for applications in plant sciences, agriculture and ecology. In this paper, possible techniques to develop models that allow the use of ERT to spatialise soil water available to plants are reviewed. An application of soil wate…
Molecular characterization of <em>Vitis vinifera</em> L. local cultivars from volcanic areas (Canary Islands and Madeira) using SSR marke…
2019
Aim: This study characterises and identifies 79 grapevine accessions from the Canary Islands and 14 from Madeira using simple sequence repeat (SSR) analysis.Methods and Results: A kit of 20 microsatellites or simple sequence repeats (SSRs) were used to obtain the molecular profiles of the 93 accessions in this study. The results allowed us to identify four new cultivars (Bienmesabe tinto, Burra volcanica, Vallera, Verijadiego negro), two new colour mutations (Listan rosa, Mollar cano rosado) and two unknown molecular profiles from Madeira. Furthermore, we propose that eight names of varieties be included in the Vitis International Variety Catalogue (VIVC) as prime names, and 38 accession na…
Cover Crop and Pruning Residue Management to Reduce Nitrogen Mineral Fertilization in Mediterranean Vineyards
2021
This paper aimed to study the effect of temporary cover crop and vine pruning residue burial as alternative practices to conventional tillage on soil nitrate (NO3-N) availability and grapevine performance in the short term. The trial was carried out in a rain-fed vineyard (Vitis vinifera L., cv Grecanico dorato/140 Ruggeri) located in a traditional Mediterranean viticultural area (37°