Compared to even the dumbest human being, your average tulip is a moron. But you’d have to be dumber than a tulip to deny that something — maybe not intelligence in its dictionary definition, but some guiding, autonomic power — is at work among the members of the plant kingdom. And if we grant plants this quasi-intelligence, then we have to concede that some of them must be smarter than others—cannier absorbers of bugs and sun, better users of their varied environments. Inevitably, then, the question is: Which one’s smartest?
For this week’s impressive multi-purpose mechanism of spore dispersal, but the real reason I rate it so highly is that it is from a group older than the dinosaurs, and hence has hung around with little change for 250+ million years, and yet still manages to outwit human begins, for all our supposed smartness, by being an almost ineradicable garden weed! If pulled up, the underground stems simply break, effectively propagating the plant.
Philippa Borrill
Lecturer, Plant Biology, University of Birmingham
This may sound a bit kooky, but I think that crop plants are the smartest plants on the planet. We often think about crops as being domesticated by humans, but I would argue that the reverse is also true. The crops we depend on have domesticated (or perhaps even enslaved) us to sow their seeds for them, water and care for the growing plants, and then harvest the seeds and make sure they get planted the next year (although obviously we do eat many of them too!).
In particular, wheat is grown on more land area across the world than any other crop. This is quite an amazing feat for a plant which originated in the fertile crescent, a relatively small area in the Middle East and Mediterranean about 10,000 years ago. Now humans sow wheat across five continents (North America, South America, Europe, Asia and Africa) and wheat has adapted to grow in a huge range of environments—from the hot, dry environment in Australia to the cool wet climate of the UK. Globally we produce ~750 million tons of wheat every year, which equates to 1.5 x 1019 individual wheat grains (the ridiculously big number 15,000,000,000,000,000,000) and it provides food for over 2.5 billion people every day. If that’s not a smart plant I’m not sure what is.
Olivia Wilkins
Assistant Professor, Plant Science, McGill University, and leader of the Plant Systems Biology research group
Plants are able to do so many clever things: they can build their bodies from atmospheric gasses and sunlight; their seeds can persist in the soil for years (and in some cases centuries); they can woo animal pollinators to transport their gametes; and they do it all without a central processing organ analogous to a brain. But given that these traits are common to most plants, I think the criteria that I’d used to pick out the smartest ones would be their ability to grow and thrive in unpredictable environmental conditions.
Most plants have evolved in the context of the long term climate of the areas in which they are endemic, and they grow well there. Plants that have been moved around by humans, like crops, have been bred to grow and produce (somewhat) reliable yields in a variety of site specific climates. But the challenge that plants are facing now is really hard. They are confronted by environments that are not only changing rather quickly, but which are punctuated by unfamiliar temperature and precipitation extremes. Some plants won’t be up to the challenge and they will become extinct. In the case of crops, this could be a disaster.
Fortunately, plants are already accustomed to responding to changing environments. Daily, they are confronted by energy rich periods of light and energy poor periods of darkness; they protect themselves against drying out by restricting their water use in dry times. They do this by employing flexible and dynamic subcellular structures called gene regulatory networks. One of my favourite examples of the power of regulatory networks to expand the environments in which plants can grow was discovered in rice. Most varieties of rice plants will die if they are completely submerged in water during the flash floods that can follow monsoons. But some rice varieties can tolerate complete submergence for more than a week. It turns out that plants that can tolerate submergence have a regulatory network controlled by a protein called sub1. Moreover, it turns out that if you move the gene encoding sub1 to rice varieties that are sensitive to submergence they become tolerant to it. Evolution has clearly targeted regulatory networks to expand the variety of conditions in which plants can grow, and I believe that these networks are the most accessible targets for defending plants against the new challenges presented by climate change.
But as for the question of which plant is the smartest? I don’t know. But I’m very hopeful that we’ll continue to discover and explore ways in which nature has already solved our most pressing plant questions.
David Duffy
Professor, Botany, University of Hawaii at Manoa
Plants are way smarter than people, who are just walking shadows; poor players, who strut and fret their hour upon the stage (to paraphrase the Bard). I’d say what makes a plant smart is surviving—like street smarts. Here are three examples.
Llangernyw Yew in churchyard North Wales: 5,000 years old.
Jurupa Oak Quercus palmeri in Riverside, CA: 13,000 years old.
Pando’ Quaking aspen in Utah: 80,000 years old.