ABSTRACT
This study was conducted to assess particulate matter pollution and the accumulation of airborne toxic metals by studying the foliar deposition pattern in an urban environment. To this end, two commonly growing plants (Senna siamea (Lam.) H.S.Irwin & Barneby and Alstonia scholaris (L.) R.Br.) from the busiest traffic squares of the city (Nehru Chowk) in Bilaspur, India, were selected for detailed study. For this purpose, plant leaf samples of both plant species were collected from pollution-affected areas and a reference site (unpolluted) in the city and examined by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) to estimate the accumulation of PM-bound toxic metals at the leaf surfaces. The results of this study showed that the leaves of both plants accumulate PM in different size ranges. Although both plant leaves showed accumulation of PM from respirable suspended particulate matter (RSPM) to ultra-fine particles (UFPs: < 0.1: less than 100 nm) range along with toxic metals, S. siamea retained a higher level of PM than A. scholaris due to better micro-morphological properties on both leaf surfaces. The size of some PM was found to be smaller than the stoma openings. The EDS study proved the presence of harmful airborne toxic metals (Pb, Cd, Cu, Zr, Al, Co, etc.) in these PMs of ambient air. This indicates that toxic metals can enter the leaves through stomatal openings. The results of this study recommended that both plants can be used as a tool to minimise PM pollution.
ABSTRACT
Monoterpenes are volatile organic compounds that play important roles in atmospheric chemistry, plant physiology, communication, and defense. This review compiles the monoterpene emission flux data reported for different regions and plant species and highlights the role of abiotic environmental factors in controlling the emissions of biogenic monoterpenes and their emission fluxes for terrestrial plant species (including seasonal variations). Previous studies have demonstrated the role and importance of ambient air temperature and light in controlling monoterpene emissions, likely contributing to higher monoterpene emissions during the summer season in temperate regions. In addition to light and temperature dependence, other important environmental variables such as carbon dioxide (CO2), ozone (O3), soil moisture, and nutrient availability are also known to influence monoterpene emissions rates, but the information available is still limited. Throughout the paper, we identify knowledge gaps and provide recommendations for future studies.
ABSTRACT
In this study, we examined 49 representative plant species of the Achanakmar-Amarkantak Biosphere Reserve (AABR) forest of Central India for emission of a number of biogenic volatile organic compounds (BVOCs). The BVOCs emissions from seven plant species are reported here for the first time. The emission rates of different plant species were ranged from negligible to 80.6 ± 0.82 (µgg-1 h-1). Forty-seven plant species were found to emit isoprene and monoterpenes (23 high emitters, 12 moderate emitters, and 12 low emitters). Dalbergia sissoo showed the maximum total average volatile organic compound (TAVOC) emission rates (80.6 µgg-1 h-1). The percentage composition of monoterpenes was also varied across different plant species. Alpha-pinene (α-pinene) was found as the most dominant monoterpene with about 41.40% of the total monoterpene emission. The highest emission range of α-pinene (7.8 µg g-1 h-1) was observed in Murraya koenigii. Carene was emitted only from two species (i.e., Mangifera indica and Terminalia tomentosa). When the emission rates of present study were compared to previous studies, there were considerable differences even for the same species. The study also reports the emission of BVOCs from Shorea robusta for the first time which is the most dominant plant species of the AABR (covering 60% of the total forest area).
