Role of acid phosphatase and enzymatic and non-enzymatic antioxidant systems in tolerance of alfalfa (Medicago sativa L.) populations to low phosphorus availability
¹Sultan Moulay Slimane University, Polydisciplinary Faculty of Beni-Mellal, Polyvalent Unit on R&D, Mghila, PO Box. 592, MA23000 Beni-Mellal, Morocco
²Sultan Moulay Slimane University, Polydisciplinary Faculty of Beni–Mellal, Unit of Biotechnology & Sustainable Development of Natural Resources, Mghila, PO Box. 592, MA23000 Beni-Mellal, Morocco
³Cadi Ayyad University, Faculty of Sciences Semlalia, Laboratory of Water, Biodiversity and Climate Change, Bd Prince Moulay Abdellah, MA40000 Marrakech, Morocco
*Correspondence: omarfarssi@gmail.com
Abstract:
This study aims at evaluating the tolerance of four alfalfa (Medicgao sativa L.) populations to low phosphorus (P) in rooting medium. The experiment was carried out under controlled conditions. The seedlings of 15 old days were subjected to P deficiency using Ca3HPO4, insoluble form and P sufficiency using KH2PO4, as soluble form, at a final concentration of 250 μmol P plant−1. week−1. After 60 days P deficit, several agro–physiological and biochemical traits were measured and determined in both conditions. The obtained results indicated that the P–starvation significantly (P < 0.001) reduced the agroeconomic traits evaluated such as plant dry weight and leaf area. The root and shoot P contents were found (P < 0.001) decreased by low–P availability in the rooting medium. This constraint induced significant (P < 0.001) increase in phosphatase acid activity and caused lipid peroxidation and oxidative damage to cells, evaluated through malondialdehyde and hydrogen peroxide contents. Our results showed also, that low P availability significantly (P < 0.001) increased the enzymatic antioxidant responses reflected by the activities of superoxide dismutase (SOD), guaiacol peroxidase and catalase. The non-enzymatic antioxidant molecule such as proline and total polyphenols were found significantly increased in alfalfa stressed plants. The behavior of alfalfa populations tested was significantly different (P >0.05). The OL population was found to be the least affected and the DEM was most sensitive one, whereas the populations TATA and RICH showed a moderate tolerance. Our study advises that the tolerance of Moroccan alfalfa populations to low P–availability was associated with increased acid phosphate activity and ability to induce enzymatic and non-enzymatic antioxidant responses leading to cell detoxification from reactive oxygen species (ROS).
Key words:
acid phosphatase, alfalfa, antioxidant activity, oxidative stress, Phosphorus, ROS