Investigating the Effect of Dust on the Rate of Photosynthesis and Air Pollution Tolerance Index of the Leaves of Ziziphus spina-christi (L.) Willd. in the City of Ahvaz

Background Aims: Dust is one of the phenomena affecting the environment’s quality. The change in the vital indices of plant species is one of its important effects. The present study was conducted to investigate the effect of dust on the rate of photosynthesis and air pollution tolerance index (APTI) of the leaves of Ziziphus spina-christi (L.) Willd. in the city of Ahvaz in 2020. Methods: A number of 10 Z. spina-christi (L.) Willd. trees were selected in each municipal district of Ahvaz metropolis. From each tree, one leaf sample was selected in the 4 main geographical directions, i.e., 4 samples from each tree species; overall, 40 leaf samples were collected in the whole region and sent to the laboratory to investigate the level of dust particles deposited in the four seasons of the year. Photosynthesis was measured based on the amount of chlorophyll by a spectrophotometer, and the APTI was calculated using Agbaire et al.’s method. Results: The results of measuring the weight of dust deposited on the leaves of Z. spina-christi (L.) Willd. trees in the city of Ahvaz showed that the greatest amount of dust was deposited on the leaves in the geographical north direction. The highest rate of photosynthesis was in the fall (53.76), and the lowest was in the spring (35.97). The mean APTI score of Z. spina-christi (L.) Willd. species in Ahvaz was 4.77. Conclusion: These results indicate that this species has a favorable APTI against environmental pollutants, including dust. In general, the results of the present study confirm the significant association of the dust deposited on the leaves of Z. spina-christi (L.) Willd. with the rate of photosynthesis and the APTI.