This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Plants of the same species can differ considerably in their chemical composition, affecting their smell, taste and even toxicity. A new study shows that the term "chemotype" has not been used consistently.
"Until recently, plants of the same species were assigned to different chemotypes without precisely defining which organ and which chemical family were investigated," says Dr. Caroline Müller, a professor and lead author of the study. "With our systematic approach, we are establishing clearer criteria for defining what exactly constitutes a chemotype." The findings are published in the journal Trends in Plant Science.
A chemotype describes plants within a species that differ in specific chemical compounds. These include terpenoids and alkaloids, for example—compounds that plants use, among other things, to influence herbivores or pathogens. Differences between chemotypes are largely genetically determined.
Environmental conditions can, however, further modify the precise chemical composition. The plant organ examined also matters: Leaves, flowers and roots can have different chemical profiles. Using common tansy (Tanacetum vulgare), researchers demonstrate how strongly the classification of a chemotype can depend on which chemical family is examined.
Without consistent criteria, findings from different studies can be compared only to a limited extent. These differences also matter for practical applications. Tansy was formerly used as a "worm herb" to treat intestinal worms.
Depending on the chemotype, however, the plant can vary in toxicity. Another example is cannabis: Different chemotypes can differ considerably in their THC (tetrahydrocannabinol) content and, consequently, in their effects. Knowledge about chemotypes may also be relevant to agriculture.
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