Department of Environmental Science, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland.
J Exp Bot. 2010 Jun;61(6):1583-95. doi: 10.1093/jxb/erq034. Epub 2010 Feb 24.
Volatile organic compounds (VOCs) are expected to have an important role in plant adaptation to high temperatures. The impacts of increasing night-time temperature on daytime terpenoid emissions and related gene expression in silver birch (Betula pendula) and European aspen (Populus tremula) clones were studied. The plants were grown under five different night-time temperatures (6, 10, 14, 18, and 22 degrees C) while daytime temperature was kept at a constant 22 degrees C. VOC emissions were collected during the daytime and analysed by gas chromatography-mass spectrometry (GC-MS). In birch, emissions per leaf area of the C11 homoterpene 4,8-dimethy1-nona-1,3,7-triene (DMNT) and several sesquiterpenes were consistently increased with increasing night-time temperature. Total sesquiterpene (SQT) emissions showed an increase at higher temperatures. In aspen, emissions of DMNT and beta-ocimene increased from 6 degrees C to 14 degrees C, while several other monoterpenes and the SQTs (Z,E)-alpha-farnesene and (E,E)-alpha-farnesene increased up to 18 degrees C. Total monoterpene and sesquiterpene emission peaked at 18 degrees C, whereas isoprene emissions decreased at 22 degrees C. Leaf area increased across the temperature range of 6-22 degrees C by 32% in birch and by 59% in aspen. Specific leaf area (SLA) was also increased in both species. The genetic regulation of VOC emissions seems to be very complex, as indicated by several inverse relationships between emission profiles and expression of several regulatory genes (DXR, DXS, and IPP). The study indicates that increasing night temperature may strongly affect the quantity and quality of daytime VOC emissions of northern deciduous trees.
挥发性有机化合物(VOCs)预计在植物适应高温方面发挥重要作用。本研究探讨了夜间温度升高对银桦(Betula pendula)和欧洲山杨(Populus tremula)无性系白天萜烯排放及其相关基因表达的影响。这些植物在五个不同的夜间温度(6、10、14、18 和 22°C)下生长,而白天温度保持在 22°C 的恒定水平。通过气相色谱-质谱联用仪(GC-MS)收集白天的 VOC 排放物并进行分析。在桦树中,叶片面积单位的 C11 同倍半萜 4,8-二甲基-壬-1,3,7-三烯(DMNT)和几种倍半萜的排放一直随夜间温度升高而增加。总倍半萜(SQT)的排放随着温度的升高而增加。在山杨中,DMNT 和β-罗勒烯的排放从 6°C 增加到 14°C,而其他几种单萜和 SQTs(Z,E)-法呢烯和(E,E)-法呢烯增加到 18°C。总单萜和倍半萜的排放在 18°C 时达到峰值,而异戊二烯的排放则在 22°C 时下降。在 6-22°C 的温度范围内,桦树的叶面积增加了 32%,山杨的叶面积增加了 59%。两个树种的比叶面积(SLA)也增加了。VOC 排放的遗传调控似乎非常复杂,这表明排放谱与几个调节基因(DXR、DXS 和 IPP)的表达之间存在一些反比关系。该研究表明,夜间温度升高可能会强烈影响北方落叶树白天 VOC 排放的数量和质量。