Isotopic composition of CO emitted by plants under the influence of light and temperature
Summary
In this study, the influence of light and temperature on plant emitted carbon monoxide has
been investigated. This was done by using a dynamical sampling method directly connected to
a CO isotope measurement system. Plant material was put into a quartz reactor and was either
irradiated with light or the reactor was heated in an oven. Emission rates and isotopic composition
of C and O isotopes have been determined. Light experiments have been performed with fresh
leaves and dried leaves. All plants showed emission of CO when irradiated with solar simulated
light. Fresh plants showed an average δ 13 C value of 43.67 ± 3.64 ‰ and an average δ 18 O of 26.14
± 4.25 ‰. Drying of the plants decreased the δ 18 O value. Additionally the influence of UV was
investigated by blocking UVB with a glass plate or blocking UVA and UVB with a transparent
plastic plate. These tests showed that blocking UVA and UVB decreases the emission and increases
the δ 13 C value. Temperature increase to 30 - 50 °C also induced CO emission from leaves. The
results of the temperature experiments showed large variability in terms of emission rate and
isotopic composition. It is suggested that temperature but also the storage time of plant material
increases the δ 13 C value.