Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
Ann Bot. 2013 Jan;111(1):21-30. doi: 10.1093/aob/mcs228. Epub 2012 Oct 22.
Plants use a diverse range of visual and olfactory cues to advertize to pollinators. Australian Chiloglottis orchids employ one to three related chemical variants, all 2,5-dialkylcyclohexane-1,3-diones or 'chiloglottones' to sexually attract their specific male pollinators. Here an investigation was made of the physiological aspects of chiloglottone synthesis and storage that have not previously been examined.
The location of chiloglottone production was determined and developmental and diurnal changes by GC-MS analysis of floral tissue extracts was monitored in two distantly related Chiloglottis species. Light treatment experiments were also performed using depleted flowers to evaluate if sunlight is required for chiloglottone production; which specific wavelengths of light are required was also determined.
Chiloglottone production only occurs in specific floral tissues (the labellum calli and sepals) of open flowers. Upon flower opening chiloglottone production is rapid and levels remain more or less stable both day and night, and over the 2- to 3-week lifetime of the flower. Furthermore, it was determined that chiloglottone production requires continuous sunlight, and determined the optimal wavelengths of sunlight in the UV-B range (with peak of 300 nm).
UV-B light is required for the synthesis of chiloglottones - the semiochemicals used by Chiloglottis orchids to sexually lure their male pollinators. This discovery appears to be the first case to our knowledge where plant floral odour production depends on UV-B radiation at normal levels of sunlight. In the future, identification of the genes and enzymes involved, will allow us to understand better the role of UV-B light in the biosynthesis of chiloglottones.
植物利用多种视觉和嗅觉线索来向传粉者宣传。澳大利亚 Chiloglottis 兰花使用一种到三种相关的化学变体，全部为 2,5-二烷基环己烷-1,3-二酮或“chiloglottones”，以吸引其特定的雄性传粉者。在此，对以前未检查过的 chiloglottone 合成和储存的生理方面进行了研究。
确定 chiloglottone 产生的位置，并通过 GC-MS 分析花组织提取物监测两种亲缘关系较远的 Chiloglottis 物种的发育和昼夜变化。还进行了光照处理实验，使用耗尽的花朵来评估阳光是否是 chiloglottone 产生所必需的；还确定了所需的特定波长的光。
chiloglottone 仅在开放花朵的特定花组织（唇瓣和萼片）中产生。开花后，chiloglottone 的产生迅速，并且昼夜之间的水平或多或少保持稳定，并且在花的 2 到 3 周寿命期间保持稳定。此外，确定 chiloglottone 的产生需要连续的阳光，并确定阳光在 UV-B 范围内（峰值为 300nm）的最佳波长。
UV-B 光是合成 chiloglotones 所需的，这是 Chiloglottis 兰花用于吸引雄性传粉者的性引诱半化学物质。这一发现似乎是我们所知的第一个案例，植物花的气味产生取决于正常阳光水平下的 UV-B 辐射。将来，鉴定涉及的基因和酶，将使我们能够更好地理解 UV-B 光在 chiloglotones 生物合成中的作用。
