For the first time, researchers have shown that plants can make “decisions” based on risk. In a paper just published in Current Biology, scientists from Oxford University and Tel-Hai College show that the pea plant can make choices depending on perceived risk factors. The plants were more likely to take risks when nutrient levels were low but became risk averse when nutrients were readily available.
Researchers grew pea plants and split their roots between two separate pots. In order to keep growing, the plant would have to “decide” which pot to prioritize. As previous research had shown, the plants would generally be biased toward the pot that offered better growing conditions. The researchers wondered what would happen if both pots contained, on average, the same amount of nutrients. One pot would contain nutrients at a constant concentration while the other would vary over time.
Interestingly, the plants prioritized pots based on if the average concentration of available nutrients was high or low. If the average concentration of nutrients between the pots was high, the plants would grow roots in the pot with constant conditions. If the average concentration of nutrients was low, the pea plants were more likely to grow roots in the pot with variable conditions. In other words, if they were getting enough nutrients overall, they’d stick to the pot that had an unchanging supply. If nutrients were too low, they would take a risk by growing in the varied concentration pot, where they had a chance of gaining more nutrients later.
The pea plants demonstrated risk aversion when they had enough nutrients to grow, taking the safer route by growing in the pot with unchanging conditions. If they lacked nutrients, however, they’d show risk prone behaviors by favoring the variable pot. This is the first time that such risk sensitivity has been shown in plants. The researchers hope that future studies will reveal how the plants make these choices.
Dener, Efrat et al. Pea plants show risk sensitivity. Current Biology (2016).