Sunday, November 02, 2008

Vetiver - soil microbes create the scent and create healing properties, too

Photo of soil microbe Rhizobium beneficially infecting the root of black eyed peas. The swollen nodules are the little "houses" the Rhizobium built by tunneling into the root. The Rhizobium supplies nitrogen to the plant, thus lessening the need for nitrogen fertilizer, cutting down on water pollution and costs.

I love looking at the cycle of nature and how it relates to perfumery. Taste and scent are closely related, soil health and plants are a given equation, and how the world of insects and microbes interact with all of the above is fascinating.

I have a background of study in agriculture, plant science and economic botany. I took courses in plant physiology, plant ecology, soil science and various other related subjects. It always is a wonder and a delight to read of yet another secret unlocked by plant scientists. The latest bit of information added to our knowledge database involves the symbiotic relationship between soil microbes and the roots of vetiver plants. Vetiver, prized in the cosmetic, aromatherapy, Ayurvedic and perfumery arts, is the only grass root used for its scent. Deep, earthy vetiver - you can smell the earth and water in it. Dry, grounding and containing fixative properties (it can help the drydown of a perfume in extending the life of the perfume), vetiver roots now show us how they evolved with another biological entity - a lively soil bacteria - to create its scent.

Not only is the scent made more complex and valuable because of the soil microbes, these microbes also add properties of antibacterial, antioxidant and insecticidal to the list of uses for vetiver oil. To quote the article: "microbiologists Pietro Alifano and Luigi Del Giudice, the plant biologist Massimo Maffei and their colleagues found that Vetiver root cells produce a few oil precursors, which are then metabolised by the root bacteria to build up the complexity of the Vetiver oil."

The ability to look at the cellular level of plants, their root zone and the soil was opened up to me at Cal Poly San Luis Obispo and the University of California, Riverside. Those schools housed fabulous plant and soil science departments, and I loved to soak all that knowledge in. I must admit I have forgotten a lot over the years, but some things really are memorable: soil science lab where we actually tasted soils. Yes, acid soil is sour, and alkaline soil is sweet. The scent of wet earth after a rain is mostly due to the expelled gas of soil microbes - I think - I do admit my memory is a little fuzzy there.

Soil is not just "dirt" under our feet. It is a world unto itself, teeming with microbes, insects and charged with gases like nitrogen and oxygen. It's a veritable other world under our feet, and we're still discovering its secrets every day.

Back in the late 70's, my ex-husband was a soil microbiologist working towards his PhD and I was his non-science-oriented helper. I still learned a lot about nitrogen-fixing bacteria increasing the yield of black-eyed peas, gas chromatographs and massspectromaters, the patience and precision needed in scientific studies, and most of all, the need to keep your eyes open to all possibilities in the biological world - there are always surprises and discoveries to me made.

This vetiver/microbe discovery is just joyful to me. I love this stuff. My mind races ahead, fantasizing about soil or ocean discoveries to be made in the future - maybe one will give us a replacement for the musk deer sac so prized, and now prohibited, in perfumery.

One amazing story remains with me from those studies so long ago, and reinforces the desire to experiment after closely observing the forces of nature: some scientist went to South America and noticed the forest-dwelling people applying mud to their cuts and scrapes. Aren't we taught to keep out cuts and scrapes as clean as possible? This schmutzing of a wound confounded the scientists, so they took samples of the soil and found the fungus Streptomyces present. It was the fungus that was antibacterial, and that lead to the development of actinomycin antibiotics, which have saved many lives.

Here are some older links from the website hosting the article cited here. They might be oldies but goodies, but they really interest me: how Turkish essential oils like rosemary and peppermint are better at defeating aphids on plants that other methods (my opinion: the oils don't have to be Turkish.) Or another article on how oregano oil may combat drug-resistant bacteria - funny - on one hand the bacteria help the plant, but the oils from a plant can be used against the microbes.

Just a fun musing on a lazy Sunday afternoon to share with y'all. Motto: don't underestimate dirt - or bugs. It's all a part of the cycle of life, and the air we breathe, the food we eat, the perfume we wear - it's all connected.

3 comments:

  1. Very useful and fascinating info.

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  2. Not only was it useful and fascinating, Amanda, it brought me back in touch with an old friend from the aggie school! Thirty years have passed, and we're catching up, and I also put her in touch with my ex - they were colleagues.

    Nice story all around!

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  3. A low cost, green eco friendly, healthy natural way to deal with aphids is to make a homemade liquid from soapberry which grows on the Chinaberry tree and has been used for thousands of years. It works very effectively.

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