Articles
Effect of drought stress on olive leaf water status, biochemical composition, fruit oil content and olive oil quality
Article number
1409_1
Pages
1 – 6
Language
English
Abstract
We evaluated the effect of deficit irrigation on leaf relative water content (RWC), stomatal conductance (gs), midday shoot water potential (ΨMD), total chlorophylls, soluble sugar, total polyphenols, orto-diphenols, flavonoids and antioxidant activity in adult olive trees (‘Cobrançosa’) in field growing conditions in 2019. Five irrigation treatments included: a fully irrigated control (FI); two sustained deficit irrigation treatments (30 and 60% of FI), and two regulated deficit irrigation (RDI) treatments.
The control received an amount of water equivalent to 100% of estimated evapotranspiration (ET). The RDI100 treatment was irrigated like the control, except during the pit hardening period, in which irrigation was reduced to 10% of FI. The RDI60 treatment was irrigated at 60% of FI from the start of the season and irrigation was cut off during the pit hardening period, after which irrigation resumed at 60% of FI. Severe water stress (RWC=77%) led to a reduction of 42% in ΨMD and 28% in gs compared to FI. Total chlorophylls and total sugar content were significantly reduced by water stress.
In contrast, water shortage activated the accumulation of proline content, total polyphenols, and increased antioxidant activity.
The content of total flavonoids seems to have been unaffected by the level of water stress.
Oil concentration was reduced by 15% under conditions of severe water stress compared to the control while in other deficit irrigation treatments, reductions were very small, and differences were not statistically significant.
Total polyphenol content in olive oils was enriched by water stress in all deficit irrigation treatments, especially in the two RDI treatments with an increase that ranged from 59 to 64% relative to the control.
The control received an amount of water equivalent to 100% of estimated evapotranspiration (ET). The RDI100 treatment was irrigated like the control, except during the pit hardening period, in which irrigation was reduced to 10% of FI. The RDI60 treatment was irrigated at 60% of FI from the start of the season and irrigation was cut off during the pit hardening period, after which irrigation resumed at 60% of FI. Severe water stress (RWC=77%) led to a reduction of 42% in ΨMD and 28% in gs compared to FI. Total chlorophylls and total sugar content were significantly reduced by water stress.
In contrast, water shortage activated the accumulation of proline content, total polyphenols, and increased antioxidant activity.
The content of total flavonoids seems to have been unaffected by the level of water stress.
Oil concentration was reduced by 15% under conditions of severe water stress compared to the control while in other deficit irrigation treatments, reductions were very small, and differences were not statistically significant.
Total polyphenol content in olive oils was enriched by water stress in all deficit irrigation treatments, especially in the two RDI treatments with an increase that ranged from 59 to 64% relative to the control.
Authors
A.A. Fernandes-Silva, P. Marques, A. Aires, T. Brito
Keywords
anti-oxidant activity, chlorophylls, proline, polyphenols, total sugars, regulated deficit irrigation, water stress
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