Plant & zo
The science of plants and more
The ‘I am damaged’ fragrance
Plants communicate with the world via volatiles, which we can often smell. To attract insects is a well-known reason plants emit volatiles. Less well known is maybe that plants also emit volatiles when they are damaged. This creates the smell of freshly cut grass. For this it does not matter if the plants get damaged through insects or if the damage occurs mechanically. Both result in the emission of volatiles.
Plants emit a specific fragrance bouquet when they are damaged, one that says, ‘I am damaged’. Plants nearby observe these volatiles and prepare themselves for hungry insects. This makes plants more resistant to the attacking insects, for example because they attracted predatory insects.
Can farmers use this to protect their crops against hungry insects, Japanese researchers asked. For this they wanted to know two things. Firstly would it result in less damage through insects to the plants, rice in this case. But also if it influenced the yield.
To answer these questions, the researchers exposed rice seedlings to volatiles of damaged weeds that they found nearby. The result, exposure to ‘I am damaged’ fragrance resulted in less leaves being eaten by insects.
But that not alone, exposed plants also had an increased yield. They produced more rice grains. The perception of the ‘I am damaged’ fragrance helped plants against their war against hungry insects.
Unfortunately, this research does not show if the ‘I am damaged’ fragrance is an alternative for the currently used plant protection methods. The use of insect killing insecticides allows plants not to put energy towards protecting themselves against insects. In theory, plants can then use all their energy towards growth, seed and fruit production. Therefore, it is important to investigate how this energy allocation in occurs in the field. Is this worse in the currently used methods then exposure to the ‘I am damaged’ fragrance is a useful additional, one that might result in less use of insecticides.
Shiojiri, K., Ozawa, R., Uefune, M., Takabayashi, J. (2021) Field-Grown Rice Plants Become More Productive When Exposed to Artificially Damaged Weed Volatiles at the Seedling Stage. Frontiers in Plant Science 12:1419