Since plants generally can’t move around, they have to rely on other strategies to cope with animals eager to turn them into a meal. Chemical weapons are a significant part of plants’ defensive arsenal. For example, thousands of plant species produce precursors of the deadly poison hydrogen cyanide; when an animal eats the plant, the precursors get converted into cyanide, which kills the offending animal. Continue reading
In response to my recent post about the dynamic life of plants, reader tmso asked about whether plants can sense and respond to smoke. I still haven’t found anything about an immediate response to smoke, but I’ve learned quite a bit about how smoke and fire affect germination. Many plants, especially in areas with a Mediterranean environment, are ‘fire followers’ that germinate after a fire has cleared the landscape. Some of them have seeds coated with flammable oils which release a lot of heat when they burn, causing the seed to germinate. Other plants, though, don’t respond to the fire itself, but germinate and grow better in response to smoke. Over the past decade, we’ve started to understand how these plants sense smoke, though there’s still a lot discover. (Thanks for the question, tmso!) Continue reading
In Lewis Caroll’s Through the Looking Glass, Alice wanders into a garden with flowers that can talk — the “garden of Live Flowers”. Of course, all plants are alive, but here the flowers are called “live” because they can talk. One of the greatest examples of human arrogance might be our attitude towards plants. We treat plants as objects, as part of the background, as mere things without any agency. We tend to forget that they’re dynamic, complex living creatures that react and respond to their environment — just in unfamiliar ways and on a different timescale. Continue reading
Around a year ago I wrote about a study which showed that micro-RNAs from plants that were eaten could regulate genes in the animal that ate them. It was an exciting and important finding. The study claimed that the miRNAs survived passage through the digestive tracts of mice, got into their bloodstream and traveled to their liver, where they regulated genes involved in cholesterol metabolism. This week I read a post on Virginia Hughes’ blog Only Human where she discusses several follow-up studies which haven’t been able to reproduce the original results. That doesn’t necessarily mean the study was wrong, but it certainly raises doubts. In her post, Virginia also links to a rebuttal letter she received from the author of the original study, so it looks like the debate is on! I’ll try to keep an eye on the subject and report back about it as things develop, but in the meantime read Virginia’s excellent summary of the current state of affairs. Showing that creatures can directly regulate genes in organisms of another kingdom of life would be a major finding, so I’m really glad that there’s debate about it. That’s how science should work: we should try to repeat studies, remain critical and open-minded, and challenge each other.
In the 1990s, Suzanne Rutherford and Susan Lindquist were studying fruit flies with a mutated version of the Hsp90 gene and found that the absence of this single gene led to a wide range of developmental defects. This was surprising not only because Hsp90 isn’t directly related to development, but also because of the remarkable breadth of its impact. Uncovering how this gene affects so many aspects of development has led to an intriguing story linking responses to environmental stress with the evolution of developmental pathways.