Abstract

THE EFFECT OF GASEOUS AIR POLLUTANTS AND ASCORBIC ACID ON SOME MINERAL ELEMENTS CONTENT OF BEANS (PHASEOLUS VULGARIS L.) PLANT IN RIYADH CITY, KINGDOM OF SAUDI ARABIA

Mohammed Abdul Rahman Al-Muwayhi

Abstract

Air pollutants such as ozone, the sulfur dioxide, nitrogen dioxide, the solid particles and organic compounds are considered the most important pollutants that directly affected the plants and lead to changes in the concentration of mineral elements in plant tissues. Identifying the impact of these pollutants is very important in determining the sensitivity of plant species and its tolerance. This study was conducted at three locations varying pollution ozone, sulfur dioxide and nitrogen dioxide gases in Riyadh city.The seeds of beans (Phaseolus vulgaris L.) were planted in the greenhouse belonging to Department of Botany and Microbiology, Faculty of Science, King Saud University, where it was put three pots for each concentration of ascorbic acid (zero, 50, 200, 400 mg/L) each of which three seeds of beans. The seeds were cultivated on 20 May 2011, and left until the completion of the growth of primary leaves, then transferred to the study sites, i.e. King Saud University, the first industrial city, and the cement factory. The results showed that the concentration of gases contaminated air in the city of Riyadh was gradually increased during the study period. The concentration of ozone and sulfur dioxide gases at the cement factory site were 87 ppb and 27 ppb, respectively. The highest concentration of nitrogen dioxide was 27 ppb at the first industrial city. Our experiment also showed that these three pollutants gases caused as a significant effect on the concentration of some mineral elements, i.e. phosphorus, potassium and carbon in beans plants treated with 400 mg/L of ascorbic acid. The concentration of phosphorus, potassium and carbon elements were 2.15,94 mg/L and 35.1%; 1.94, 88 mg/L, 32.6% and 1.89, 83 mg/L and 31.4% in beans plants growing in king Saud university, industrial city and cement factory sites, respectively.This study proved the role of ascorbic acid in resistance of plant to oxidative effects of ozone. The role of ascorbic acid resolved in the elimination of toxicity of reactive oxygen species (ROS), in addition to its ability to withstand of environmental stress.

Keywords: Air pollutants, Ascorbic acid (ASA), Beans plant, phosphorus, potassium and carbon.