Chili-Fennel Communication

Gardening can be very relaxing, especially when we are looking after our plants indoors. When nobody is watching, many of us talk to them. Of course, whether or not this cheers them up or it’s just for our benefit is still a subject for debate over a glass or two.

As usual, the focus is on our communication skills and we totally ignore those of the plants. Not so with Gagliano et al who have been taking an interest in the communication skills of red hot chili peppers – not the rock band you understand, but the plants and you can read about their adventures in the Public Library of Science (1).

They had noted that plants are known to communicate chemically, both through the soil and through the air, in addition to using light at the far-red end of the spectrum. So they set out to see if that was the limit of their repertoire. They chose chili plants and watched the progress of baby plants, firstly on their own, but then in the presence of adult chili baby sitters or, more threateningly, adult fennel plants. I must admit that I was blithely ignorant about the long-standing issues between chili and fennel.

The experiments were set up so that seed germination and early growth could not be affected by chemical messages nor by light signals. The results showed that not only did more of the chili seeds germinate when fennel plants were present, but the plants grew longer roots and stems.

The question remains open as to how the seeds and seedlings knew that fennel plants were lurking around out of site, but they responded positively in two years worth of experiments. The authors speculate on weak magnetic fields and sound, but maybe the lab techs gave it away by talking to them. Whichever is the cause, chili-fennel communication is effective.


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