This is a post I wrote for the Whorled Leaves blog.

I was fascinated by an article, Loyal to Its Roots, published on June 10 in the online version of the New York Times, concerning the social life of plants. It begins:

From its diminutive lavender flowers to its straggly windblown stalks, there is nothing about the beach weed known as the Great Lakes sea rocket [shown in photo at left] to suggest that it might be any sort of a botanical wonder. Yet scientists have found evidence that the sea rocket is able to do something that no other plant has ever been shown to do. The sea rocket, researchers report, can distinguish between plants that are related to it and those that are not. And not only does this plant recognize its kin, but it also gives them preferential treatment. If the sea rocket detects unrelated plants growing in the ground with it, the plant aggressively sprouts nutrient-grabbing roots. But if it detects family, it politely restrains itself. The finding is a surprise, even a bit of a shock, in part because most animals have not even been shown to have the ability to recognize relatives, despite the huge advantages in doing so. If an individual can identify kin, it can help them, an evolutionarily sensible act because relatives share some genes. The same discriminating organism could likewise ramp up nasty behavior against unrelated individuals with which it is most sensible to be in claws- or perhaps thorns-bared competition.

The research was carried out by Susan A. Dudley, an evolutionary plant ecologist at McMaster University in Hamilton, Ontario, and a graduate student, Amanda L. File. Dr. Dudley said: "I'm just amazed at what we've found. ... Plants have a secret social life." Since publishing this research last August, Dr. Dudley has since found evidence of three other species that can also recognize their relatives.

The article continues by relating how some plants can sense potentially competing neighboring plants through subtle changes of light or by the chemicals released into soil and air, and how they take advantage of this.

The article ends by talking about the ongoing debate among plant scientists of "which of the abilities and attributes that scientists have long considered the real of just animals, like sensing, learning and memory, can sensibly be transferred to plants?" and discusses the controversy surrounding a new group, the Society of Plant Neurobiology.
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The online article includes a video of a seedling of the parasitic weed, dodder (Cuscuta pentagona), seeking out its victim (a tomato plant).

The photo of the Sea Rocket flower is taken from the New York Times article. For more photos and information about the Great Lakes Sea Rocket, see Andy's Northern Ontario Wildflowers.