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Plant density is increasing in modern olive orchards to improve yields and facilitate mechanical harvesting. However, greater density can reduce light quantity and modify its quality. The objective was to evaluate plant morphology, biomass, and photosynthetic pigments under different red/far-red ratios and photosynthetically active radiation (PAR) combinations in an olive cultivar common to super-high-density orchards. In a greenhouse, young olive trees (cv. Arbequina) were exposed to low (L) or high (H) PAR with or without lateral FR supplementation (L+FR, L-FR, H+FR, H-FR) using neutral-density shade cloth and FR light-emitting diode (LED) modules. Total plant and individual organ biomass were much lower in plants under low PAR than under high PAR, with no response to +FR supplementation. In contrast, several plant morphological traits, such as main stem elongation, individual leaf area, and leaf angle, did respond to both low PAR and +FR. Total chlorophyll content decreased with +FR when PAR was low, but not when PAR was high (i.e., a significant FR*PAR interaction). When evaluating numerous plant traits together, a greater response to +FR under low PAR than under high PAR appeared to occur. These findings suggest that consideration of light quality in addition to quantity facilitates a fuller understanding of olive tree responses to a light environment. The +FR responses found here could lead to changes in hedgerow architecture and light distribution within the hedgerow.
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The storage conditions are very critical to minimize hydrolytic and oxidative reactions of virgin olive oils (VOOs). These reactions are logically influenced by the composition of the VOO, so that each variety may have a specific behavior. The aim of this study was to evaluate changes in quality parameters and in the phenolic and triterpenic profile of Arauco VOOs, a unique local variety from Argentina, after storage under different conditions. The effects of exposure to light (darkness and light), temperature (24 and 40 °C), packaging material (polyethylene (PET) and dark glass), and headspace (air and N2 atmosphere) were investigated for 76 days. A reduction in total phenolic compounds was observed after storage treatments, but all samples still complied with the EFSA health claim after the different handlings. Overall, the results revealed that the preservation of the oils in PET appears adequate, with improved stability when N2 was used in the headspace, along with darkness and low temperature. The study of phenolic profiles showed that substances previously reported as possible markers of olive oil aging, such as hydroxytyrosol and an isomer of decarboxymethyl oleuropein aglycone, also have a similar behavior during the aging of Arauco variety oil. Interestingly, some evidence was found that another oleuropein-derived compound (oleuropein aglycone isomer 3) could also be used as an aging marker.
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A major concern for olive cultivation in many extra-Mediterranean regions is the adaptation of recently introduced cultivars to environmental conditions different from those prevailing in the original area, such as the Mediterranean basin. Some of these cultivars can easily adapt their physiological and biochemical parameters in new agro-environments, whereas others show unbalanced values of oleic acid content. The objective of this study was to evaluate the effects of the thermal regime during oil synthesis on the expression of fatty acid desaturase genes and on the unsaturated fatty acid contents at the field level. Two cultivars (Arbequina and Coratina) were included in the analysis over a wide latitudinal gradient in Argentina. The results suggest that the thermal regime exerts a regulatory effect at the transcriptional level on both OeSAD2 and OeFAD2-2 genes and that this regulation is cultivar-dependent. It was also observed that the accumulated thermal time affects gene expression and the contents of oleic and linoleic acids in cv. Arbequina more than in Coratina. The fatty acid composition of cv. Arbequina is more influenced by the temperature regime than Coratina, suggesting its greater plasticity. Overall, findings from this study may drive future strategies for olive spreading towards areas with different or extreme thermal regimes serve as guidance for the evaluation olive varietal patrimony.
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BACKGROUND: The aim of this work was to evaluate and compare oil production and its quality in three Spanish olive varieties (Genovesa, Villalonga, and Nevadillo blanco) growing outside the Mediterranean basin with the Argentine autochthonous variety (Arauco). Fruit parameters and oil characteristics were evaluated using samples collected from the germplasm collection of Mendoza province and elaborated in the same place. RESULTS: The levels of phenolic compounds and the fatty acid composition of the samples were comparable with those previously published for these Spanish varieties, grown in the Mediterranean basin, showing the adaptability of olive trees. Observing the levels of phenolic compounds and oxidative stability, a strong correlation between oxidative stability and oleocanthal was observed. CONCLUSION: The characteristics of the fruit and oil differed according to variety and season. The inter-harvest stability was different depending on the variety. Genovesa was observed to be the most stable variety according to its fruit and oil characteristics - even more stable than the autochthonous variety, Arauco. However, in terms of the composition of phenolic compounds, Arauco was the most stable between harvests, this characteristic being more important for the taste and uniformity of the product. © 2020 Society of Chemical Industry.
Assuntos
Azeite de Oliva/química , Aldeídos/química , Argentina , Monoterpenos Ciclopentânicos/química , Ácidos Graxos/química , Frutas/química , Frutas/classificação , Olea/química , Olea/classificação , Oxirredução , Fenóis/química , Controle de Qualidade , Estações do Ano , EspanhaRESUMO
BACKGROUND: 'Arauco' is the only autochthonous olive cultivar from Argentina. Little has been reported so far regarding the management of this crop. In this work, variations in fruit and chemical characteristics of olives harvested over a wide range of dates and seasons are reported for this cultivar at two sites in Mendoza province in central west Argentina. RESULTS: During the harvest periods studied, fruit oil content on a dry basis remained at its maximum and was stable, but fruit oil content on fresh basis increased as water content decreased with delay in harvest date. Harvest date affected the maturity index of fruits as well as the oxidative stability and phenolic content of oil. In contrast, the fatty acid profile was not consistently affected by harvest date. Environmental conditions, mainly the occurrence and intensity of frosts, strongly influenced oil quality as well as maturity with delay in harvest date. CONCLUSION: The most appropriate harvest time to obtain Arauco oil with a high oil yield and good chemical quality was before mid-May and with maturity index lower than 2. Fruits harvested after mid-May were exposed to minimum temperatures between -1.2 °C and - 4.0 °C, producing oil with low phenolic compounds and oxidative stability. © 2019 Society of Chemical Industry.
Assuntos
Frutas/química , Olea/crescimento & desenvolvimento , Azeite de Oliva/química , Argentina , Produção Agrícola , Ácidos Graxos/química , Frutas/crescimento & desenvolvimento , Olea/química , Oxirredução , Fenóis/química , Estações do Ano , Temperatura , Fatores de TempoRESUMO
The aims of this work were to quantify (i) the effect of the source:sink ratio on stem water potential (SWP) and (ii) the phenotypic plasticity of SWP and its relationship to oil yield components in olive. Trees with a 3-fold variation in the source:sink ratio (crown volume/fruit number per tree) were monitored in 2007-2008 and 2008-2009 in a fully irrigated orchard in Mendoza, Argentina. The combination of rainfall, irrigation, and evaporative demand led to a steady SWP largely above -1.65 MPa in 2007-2008 and a marked seasonal decline from -1.13 MPa to -2.04 MPa in trees with a medium and low source:sink ratio in 2008-2009. Plasticity was quantified as the slope of the norm of reaction for each trait. Across seasons, trees with a high source:sink ratio had a higher SWP than their counterparts with a medium and low source:sink ratio. Plasticity of SWP was highest in olives with a low source:sink ratio (slope=1.28) and lowest for trees with a high source:sink ratio (slope=0.76). The average SWP for each source:sink ratio and season was unrelated to both the source:sink ratio and yield components. On the other hand, the plasticity of SWP was positively associated with fruit number and negatively associated with the source:sink ratio, fruit weight, and fruit oil weight. The plasticity of the SWP was unrelated to SWP per se. It is concluded that understanding the effect of the source:sink ratio on plant water relations would benefit from a dual perspective considering the trait per se and its plasticity. A dual approach would also allow for more robust plant-based indicators for irrigation.