Effects of dust on forest tree health in Zagros oak forests

Abstract

Dust is one of the most devastating factors for the environment threatening all animal and plant species. In many regions, the ecological and economic impact of microdust on scarce species is critical. In the western region of Iran, the Zagros forests have been exposed to dust storms for many years. In this study, the effect of dust on oak trees, the most important trees of Zagros forests, is investigated. For this purpose, 3-year-old seedlings of three species of oak trees under natural conditions were exposed to dust during spring and summer months. Seedlings were divided into two groups; one group was assigned as dust treatment and the other as control that the control group washed regularly to remove dust. Anatomical characteristics of leaves and dust deposits on leaves during the study period were examined by scanning electron microscope (SEM). The rate of photosynthesis and gas exchange in control and treated plants was examined by IRGA, LCI. SEM images showed that stomata structure, trichome density, and epicuticular waxes of leaves are different in all three species. This difference in micromorphology of species influences the effects of dust deposited on the leaves. A comparison of leaf species images in control and dust treatment showed that in dust treatment the percentage of stomata blocked by dust in three species (per unit area) of Quercus infectoria, Q. libni, and Q. brantii were 61/6, 48/4, and 38/1%, respectively. The results of leaf gas exchange investigation indicated that stomatal occlusion by dust had a negative impact on the examined parameters of three oak species (P ≤ 0.01). Thus, gas exchange and photosynthetic rates of the treated species were significantly reduced. The results of both parts of the study showed the vulnerability of the three species to dust as Q. infectoria > Q. libni > Q. brantii. Therefore, based on these findings, dust can disrupt the physiological activities of the studied species and the continuation of the exposure to dust will accelerate the process of destruction of these forests.

Effect of Dust Types on the Eco-Physiological Response of Three Tree Species Seedlings: Eucalyptus camaldulensis, Conocarpus erectus and Bombax ceiba

“…Smaller dust particles enter the leaf through stomatal openings, and the larger particles usually pile up on the stomatal pores, affecting gaseous exchange processes, which in turn affect photosynthesis, respiration, and transpiration that allow the penetration of phytotoxic gaseous pollutants and overall plant growth [36][37][38]. In our investigation, carbon dust concentration reduced photosynthetic rate, transpiration rate, and stomatal conductance despite increasing leaf temperature in all three species, which is in line with the results of [29,[39][40][41]. However, due to the dust-loaded leaf substrate, increasing near-infrared light spectrum irradiance absorption might raise leaf temperature and photorespiration while decreasing net photosynthesis [42].…”

The Complex Issue of Urban Trees—Stress Factor Accumulation and Ecological Service Possibilities

“…Aside from these physiological impacts, poor air quality can impose mechanical changes, such as stomatal occlusion by dusts suspended in polluted air. Such changes result in the worsening of gas exchange and therefore disturb the vital processes of trees [17]. Access to water and mineral nutrients is a fundamental requirement for plant growth.…”

A review of common natural disasters as analogs for asteroid impact effects and cascading hazards

“…High concentrations of dust can have detrimental impacts on crops, as demonstrated by Hatami et al (2017, 2018) using field experiments on wheat and cowpea. Grapes (Behrouzi et al 2019 ) and oak forests (Moradi et al 2017 ) were also negatively impacted. The economic impact of reduced industrial productivity was estimated to be $US 149 million (0.04% GDP) per day for large dust events (Birjandi-Feriz andYousefi, 2017 ), mostly due to effects on workers’ health and safety as well as disruptions in transportation.…”