Isoprene emission from Indian trees

Abstract

[1] Isoprene is the most dominant non-methane volatile organic compound (NMVOC) emitted by plants. NMVOCs play an important role in regulating the composition of atmospheric trace gases including global concentration of tropospheric ozone. Our present knowledge about NMVOCs emission is mainly from studies on temperate tree species. So far information on biogenic NMVOCs emission from tropical tree species is limited. In this study, isoprene emission rates from 40 tropical Indian tree species belonging to 33 genera and 17 families were measured for the first time using a dynamic flow through enclosure chamber technique. The isoprene emission rate from plants (30°C and PAR 1000 mmolm À2 s À1 ) ranged from undetectable to 81.5 mg g À1 h À1 and values were found to be comparable with other studies on tropical tree species. Tree species screened for isoprene emission in the present study may be grouped into the four categories, proposed by Karlik and Winer [2001], namely, 18 species were negligible or BDL isoprene emitting (<1 mg g À1 h À1 ), 6 species were low emitting (1 to <10 mg g À1 h À1 ), 5 species were moderate emitting (10 to <25 mg g À1 h À1), and 11 species were high isoprene emitting (!25 mg g À1 h À1 ). Maximum isoprene emission rate (81.5 mg g À1 h À1) was observed in the case of Dalbergia sissoo Linn. It was interesting to find that Citrus limon Linn., Citrus reticulata Linn., Citrus sinensis Linn., Grevillea robusta A. Cunn., and Morus alba Linn., which were earlier reported as BDL or non isoprene emitters in US [Winer et al., 1998;Karlik and Winer, 2001] were found to be appreciably high isoprene emitters (0.61-21.60 mg g À1 h À1 ) in the present study.

Isoprene Emission from the Forest of Haryana State

“…Isoprene emission capacities of individual plant species are found to vary from BDL to 12.01 mg Cm −2 h −1 . Maximum isoprene emission capacity (12.01 mg Cm −2 h −1 ) Mishra et al, 1998;b Rao et al, 2000;c Singh et al, 1992;d Sharma et al, 1988;e Karlik and Winer, 2001;f Singh and Singh, 1988;A Varshney and Singh, 2003;B Singh, 2004. is noticed in case of Dalbergia sissoo. Three-plant species Dalbergia sisoo, Eucalyptus globulas, and Mangifera indica, comprising about 36 per cent of the Haryana forest, are found to contribute 89.6 per cent of the total isoprene emission capacity.…”

“…The isoprene emission rates values (normalised to temperature 30 • C and photosynthetically active radiation (PAR) 1000 μmolm −2 s −1 ) reported for Indian plant species including plant species of Haryana forest by Varshney and Singh (2003) and Singh (2004) have been used for the estimation of isoprene emission capacity.…”

“…Modeling (Guenther et al, 1995) and measurement studies have suggested that tropical regions contribute at least 50 per cent of the total global annual isoprene emission. Despite this limited number of measurement studies are reported from these regions Klinger et al, 1998;Kuhn et al, 2002, Otter et al, 2002Geron et al, 2002;Harley et al, 2003;Varshney and Singh, 2003). Consequently, global biogenic VOC emission estimates are largely dependent on modeling studies.…”

Seasonal Variations in Isoprene Emission from Tropical Deciduous Tree Species

“…However, measurement studies on seasonal emission patterns of tropical and subtropical plant species are extremely limited (Keller and Lerdau 1999;Kuhn et al 2004;Otter et al 2002). Commonly occurring Indian plant species have been examined for isoprene emission (Singh 2004;Varshney and Singh 2003). However, studies are altogether lacking on seasonal isoprene emission patterns of Indian plant species.…”

Effects of different doses of nitrogen treatments on isoprene emission from Ficus glomerata

“…Little information is currently available on soil nitrogen levels effects on isoprene emission. Common Indian plant species have been examined for isoprene emission (Varshney and Singh, 2003;Singh and Varshney, 2006;Singh et al, 2007 andSingh et al, 2008). However, studies are altogether lacking from the Indian sub continent on soil nitrogen levels effects on isoprene emission.…”