Morpho-physiological responses to recurrent and single drought stress suggest the presence of stress memory in grapevines

Abstract

Climate change scenarios predict increases in the frequency and severity of droughts in arid zones. Under these conditions some plants can rapidly acclimate to stress and further fortify their defenses by retaining memories of stress which enable stronger or more rapid responses if an environmental perturbation recurs. Yet, there are relatively few examples of such memory (none in perennial crops) and it is not clear if such stress memory is beneficial. We assessed the presence of drought stress memory in drip-irrigated three years old grapevines cv. Cabernet sauvignon, grown in 1 m3 containers in an arid zone of Chile. Treatments were: single drought (SD: 40 days summer-drought in the second season; well irrigated in the previous season), double drought (DD: 40 days summer-drought in the second season; 60 days summer-drought in the previous season) and a well-irrigated control treatment (WW). Morpho-physiological evaluations were performed during stress and rehydration periods during the second season. During the second stress period DD plants showed higher WUE (Anet/gs; Anet/E) than SD plants through the day, with higher values during the morning. During rehydration DD and SD reached xylem water potentials which were similar to WW while DD reaching the highest photosynthesis rate. Re-watering activated enhanced resprouting and energy transduction mechanisms (photochemical and non-photochemical quenching) in DD as compared to SD. These results were related to changes in plant architecture and morphology and can be attributed to a “stress memory” which might be beneficial for grapevines.