Weather year-to-year variations determine the influence of kaolin and salicylic acid in olive fruits and oil phenolic composition
Artigo de Conferência
Visão geral
Pesquisas
Informação adicional documento
Ver Todos
Visão geral
resumo
Olive tree (Olea europaea L.) growing area is threatened by the current and predicted
adverse environmental conditions, affecting negatively the quality of the olive products, largely
known for its benefits in human diet. Thus, agronomic strategies may be implemented to offset
those negative effects. During two consecutive years young olive trees under rainfed conditions
were sprayed in the beginning of the summer season with 100 M salicylic acid (SA), a stress
signaling phytohormone, or with kaolin 5% (KL), a heat and irradiance reflecting clay. The
distinct weather conditions during the fruit development stage, with higher rainfall close to the
harvest and the early frost events, in the first year, and the warmer and drier summer, in the second
year, contributed to the increase in phenolic compounds in fruits and in olive oil from the first to
the second year. Both KL and SA increased crop yield, while, in general, phenolics concentrations
of both olives and oil were increased and decreased by the applied products in the first and second
year, respectively. This dissimilar response was modulated by the distinct weather conditions,
demonstrating the effectiveness of the applied products in attenuating the frost-promoted
degradation of phenolic compounds in the first year and in mitigating the extreme adverse
conditions felt in the summer of the second year. The phenolic composition was also distinctly
affected, since total phenols, ortho-diphenols and flavonoids exhibited different trends. It is hard
to conclude a specific influence of the applied products on olives and oil phenolic composition,
since the weather year-to-year variations determine different plant responses.
