Ascophyllum nodosum extract enhances olive fruit quality under contrasting irrigation regimes
摘要
In line with the Green Deal strategy to reduce the impact of climate change on the agrifood system, this study evaluated the potential of a commercial biostimulant, based on an extract of Ascophyllum nodosum, to improve fruit quality. Potted olive plants, Olea europaea, from the cultivars Arbequina and Galega, were treated with A. nodosum extract or water, and then exposed to two irrigation regimes, 100% of field capacity (FC), 100% FC + biostimulant, 50% FC, and 50% FC + biostimulant for 118 days. At the end of the experiment, leaf and fruit water status, and fruit quality (width, length and metabolites) were evaluated. The results showed that this A. nodosum extract modulated tissue water availability and fruit quality in a cultivar and watering dependent way. The biostimulant was more effective in Arbequina, increasing leaf water availability under water deficit conditions, while at the fruit level, it was more successful in Galega. Regarding fruit growth, the biostimulant was effective in both cultivars, promoting fruit length and width independently of the watering condition. Moreover, A. nodosum under well-watered conditions also acted at the level of important nutritional compounds, enhancing olives of the cultivar Galega with fatty acids (oleic, palmitic, linoleic and stearic acids), squalene, sitosterol and myo-inositol, compared to plants not treated with A. nodosum under the same irrigation condition. Conversely, in Arbequina, this biostimulant seems to favor the accumulation of glucose. These results highlight the potential of this particular biostimulant based on an A. nodosum extract to improve the quality of harvested olives, and to promote olive orchards sustainability in the current scenario of climate change.