Can Biostimulants Mitigate the Negative Impact of Climate Change on Oliviculture?

Abstract

The increase of extreme climate events in the Mediterranean region represents a threat to oliviculture, one of the most important agricultural sectors in this region. Therefore, it is urgent to develop sustainable strategies that can help to mitigate the impact of climate change on olive production. The application of eco-friendly compounds, such as biostimulants, promote plant growth and yield, and seems to alleviate stress negative effects. This study aims to elucidate the effects of a biostimulant pretreatment on the water status and antioxidant battery of Olea europaea plants under well-watered and drought stress conditions. Potted young olive trees were randomly divided in two groups, one was sprayed with a biostimulant based on Ascophyllum nodosum extract and the other with water. Then, both groups were subdivided in two and exposed to drought and well-watered conditions, respectively. Drought stress treatment reduce water availability, carbohydrates levels and total flavonoids. However, biostimulant application under drought conditions helps to maintain the leaf water content and to accumulate more antioxidants, such as total phenols and flavonoids. Total soluble sugar levels were not affected by the biostimulant application under drought conditions. Starch was more responsive to the biostimulant, increasing in both treatments, well-watered and drought. These results show that this biostimulant can induce stress tolerance and alleviate drought negative effects on olive.