Alleviating Air Pollutants Impact by Some Chemicals and Planting Distance off the Freeway and Their Effect on Pears Productivity and Fruit Quality

Abstract

The goal of this study was to determine the effectiveness of exogenous application of some chemicals [Salicylic acid (SA; 200 and 400 mg/l), Ascorbic acid (AA; 1000 and 2000 mg/l), Proline (Pro; 100 and 200 mg/l), and Sodium hydrosulfide (NaHS; 250 and 500 M)] as well as planting distances (10 and 50 meters off the freeway) in alleviating air pollutants stress on "Le Conte" productivity and fruit quality of pears. During the 2019 & 2020 seasons, a study was accomplished at the 6th of October Agriculture Company. SA, AA, proline, and NaHS had a positive effect on reducing the fruit heavy metal content for the pear trees under stress. Also, SA (400 mg/l), AA, Pro (100 mg/l), and NaHS (500 μM) treatments were very helpful in increasing the tolerance index for air pollution (APTI) in pear leaves. Exogenous application of Pro, SA (200 mg/l), and AA (2000 mg/l) increased Pro in leaves. Pear trees' yield, fruit firmness, TSS, TSS/acid, V.C., total sugars, total phenolics, antioxidants, peroxidase, and superoxide dismutase were increased. Fruit from trees planted at 10 m deferred in ripening and had higher total phenolics, antioxidants, peroxidase, and superoxide dismutase.