Increases in volatile organic compound emissions of Scots pine in response to elevated ozone and warming are modified by herbivory and soil nitrogen availability

Abstract

Climate change in the boreal forests include, e.g., warming, increased tropospheric ozone concentration, higher nitrogen (N) deposition and increased risk of insect outbreaks. Climate change influences emissions of biogenic volatile organic compounds (BVOCs) affecting plant defense, communication and atmospheric feedbacks. We studied the effects of elevated temperature (ca. 1°C), elevated ozone (ca. 1.5 9 ambient), two soil N availability levels (prevailing and 120 kg N ha -1 a -1 ) and herbivory on BVOC emission rates, net photosynthesis and resin canals (BVOCs storage), of Scots pine (Pinus sylvestris) seedlings in an open-field exposure in central Finland. Shoot BVOCs were collected in July 2012 within a few days after feeding by larvae of pine-sawfly Acantholyda posticalis, a month later in August, and in May 2013. Elevated temperature caused twofold to fourfold increases in total emissions of non-oxygenated monoterpenes (MTs), oxygenated MTs and sesquiterpenes (SQTs) and several reactive compounds, and higher N enhanced some of these changes. Ozone and higher N together increased emissions of several MTs and total SQTs. Higher number of resin canals and higher net photosynthesis might have contributed to BVOC increases. Herbivory had the strongest effect on SQT emissions (threefold increase) shortly after feeding. In the following spring, herbivory reduced emission rates of some MTs, but also synergistically increased MTs emissions with temperature but suppressed the increase caused by ozone. Results suggest that warming and ozone, particularly in areas with increased soil N availability, can increase BVOC emissions from young boreal forests in the near future, and herbivory may modify these responses.

Genotype by Environment Interaction Unravels Influence on Secondary Metabolite Quality in Cassava Infested by Bemisia tabaci

“…Leaf injury has been reported to activate the phenylalanine (PAL) pathway, eventually releasing high amounts of tannins, total phenolics and increasing antioxidative capacity (Kerchev et al, 2012). This confirms that changes in multiple environmental factors may interact with plants, potentially resulting in additive (Carriero et al, 2016), synergistic (Zhang et al, 2009) or antagonistic (Kivimäenpää, Ghimire, Sutinen, HaIkio, Kasurinen, & Holopainen, 2016) effects on plants and insects.…”

Scots pine provenance affects the emission rate and chemical composition of volatile organic compounds of forest floor

“…Shoot biomass of Scots pine will increase in a warmer climate (Rasheed et al 2017), and thus the amount of litter and forest floor BVOC emissions will increase. Moreover, warming increases BVOC emissions from pine foliage (Kivimäenpää et al 2016). Therefore, BVOC emission rates are expected to increase at the forest level.…”

“…Warming affects also the BVOC composition. For example, Kivimäenpää et al (2016) showed that 3-carene emissions from Scots pine shoots were not affected by long-term warming, while α-pinene emissions were increased by a factor of 1.5-2. Such changes, as well as Scots pine chemotypes, can affect oxidative properties of the atmosphere under climate change because α-pinene is more reactive.…”

Forest Insects and Climate Change

“…Hot, dry summers can modify tree defenses and resistance to herbivory. Elevated temperature and ozone can increase the emission of volatile organic compounds and modify herbivory [84]. Temperate insects are generally cold tolerant and exhibit adaptations such as diapause and super-cooling tolerance that can facilitate shifts to northern latitudes or higher elevations even with a slight increase in temperature [85].…”