Long-term dynamics of monoterpene synthase activities, monoterpene storage pools and emissions in boreal Scots pine
<p>Seasonal variations in monoterpene emissions from Scots pine (<i>Pinus sylvestris</i>) are well documented, and emissions are often shown to follow the incident temperatures due to effects on compound volatility. Recent studies have indicated a link between monoterpene emiss...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-08-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/5047/2018/bg-15-5047-2018.pdf |
| Summary: | <p>Seasonal variations in monoterpene emissions from Scots pine
(<i>Pinus sylvestris</i>) are well documented, and emissions are often
shown to follow the incident temperatures due to effects on compound
volatility. Recent studies have indicated a link between monoterpene
emissions and physiological drivers such as photosynthetic capacity during
needle development. The complex interplay between the dynamic changes in the
biosynthetic capacity to produce monoterpenes and the temperature-dependent
evaporation process of volatiles from internal storage reservoirs has not yet
been studied under field conditions.</p><p>In this study, we analysed the relationships between needle monoterpene synthase
activities, endogenous monoterpene storage pools and monoterpene emissions
of needles in two consecutive years at a boreal forest site in Finland.</p><p>The results showed changes in the monoterpene synthase activity of needles,
linked to seasonality and needle ontogenesis, while the pool of stored
monoterpenes (about 0.5 % of dry weight) did not change considerably as a
function of needle aging. Monoterpene emissions did not correlate directly
with enzyme activity or the storage pool size. We observed notably high
plant-to-plant variation in the biosynthesis rates of individual
monoterpenes, which did not reflect the storage compound mixture. The enzyme
activity producing <i>δ</i>-3-carene was only present in the first months
after needle flushing, and decreased with needle age, whereas <i>δ</i>-3-carene was abundant in the endogenous monoterpene pool and dominated the
needle emissions.</p><p>This study emphasizes the seasonal, developmental and intraspecific
variability of monoterpene biosynthesis and storage, and calls for more
in-depth analyses to reveal how such complex interaction affects monoterpene
emissions from pine needles in boreal forests.</p> |
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| ISSN: | 1726-4170 1726-4189 |