Abstract

Wheat (Triticum aestivum L.) is a key cereal for worldwide population due to great energetic and nutritional value. However, global warming has generated a significant increase in both the temperature and the frequency of droughts that could have a negative impact on the wheat productivity, thus affecting food security. The objective of this research was to evaluate the effect of water deficit stress on physiological parameters and water status of wheat cultivars. A hydroponic experiment was conducted by using five wheat cultivars (Chevignon, Gabrio, Kiron, Maxwell, Tukan). Plants were exposed during 21 days to three levels of water deficit stress [Wc (without water stress, 0 MPa), Wm (moderate water stress, -0.2 MPa) and Ws (severe water stress, -0.5 MPa)] by adding polyethylene glycol (PEG-6000) to the culture media. At harvest, plant weight and length, relative water content, water potential, proline concentration, photosynthetic pigments and lipid peroxidation were analyzed. Plants showed a reduction of length and dry weight by water deficit stress, mostly affecting cv. Tukan. Moreover, an imbalance in water status was found in response to Wm and Ws treatments. In all wheat cultivars, differences in proline concentration were observed in roots and shoots as a consequence of exposure to water limitation. The results also showed changes in photosynthetic pigments concentration in most wheat cultivars as compared to the Wc treatment. Additionally, water deficit stress increased oxidative damage in all wheat cultivars, and this effect was more noticeable under Ws treatment. Finally, our results show a wide difference in the physiological responses to water deficit in wheat cultivars, and the choice of more tolerant cultivars is essential to guarantee successful production in environments exposed to drought conditions.