Petrichor (/ˈpɛtrɨkər/ or /ˈpɛtrɨkɔər/) is the scent of rain on dry earth,or the scent of dust after rain. The word is constructed from Greek, petra, meaning stone + ichor, the fluid that flows in the veins of the gods in Greek mythology. It is defined as "the distinctive scent which accompanies the first rain after a long warm dry spell".[1] The term was coined in 1964 by two Australian researchers, Bear and Thomas, for an article in the journal Nature.[2][3] In the article, the authors describe how the smell derives from an oil exuded by certain plants during dry periods, whereupon it is absorbed by clay-based soils and rocks. During rain, the oil is released into the air along with another compound, geosmin, a metabolic by-product of certain Actinobacteria, which is emitted by wet soil, producing the distinctive scent; ozone may also be present if there is lightning.[4] In a follow-up paper, Bear and Thomas (1965) showed that the oil retards seed germination and early plant growth.[5] This would indicate that the plants exude the oil in order to safeguard the seeds from germination under duress.
Posted on: Fri, 16 Aug 2013 16:20:46 +0000
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