The future is going to be a more stressful place for crops, with hotter summers and more frequent droughts punctuated by heavier rains. However, a new study has shown how quickly some plants can bounce back from extreme stress, offering hope that this resilience can be incorporated into our food sources.
Plants respond to stress by going into survival mode, limiting their capacity to grow until circumstances improve. Professor Barry Pogson of the Australian National University and the aptly named Dr Peter Crisp, now of University of Minnesota, exposed arabidopsis plants to dangerously bright light for an hour at a time. The plants were then allowed to recover for an hour, with their stress messengers measured.
“Plants have evolved over millennia to endure periods of drought, blistering sun and heat, among other environmental stresses,” Pogson said in a statement. “We found that plants are able to recover phenomenally well from some environmental stresses by quickly resetting to the pre-stress state.”
Pogson told IFLScience that light was chosen because it operates using similar pathways to water deprivation, but can be tested on much shorter timescales. For plants used to shady environments, even an hour a day of unfiltered sunlight can be highly stressful.
Up to a point, memory of past trauma can be helpful. The perennial grass Arrhenatherum elatius has been shown to be more resilient to drought when it has had a previously less intense dose. The trait can even be transferred to subsequent generations. However, a plant version of post-traumatic stress disorder can stultify growth when times are good. Most plants prefer to put the memory of bad times behind them, yet little research has previously been done on how they rebound.
An understanding of how plants remember or forget could help us in some capacity to anticipate the future, to shape plants to the conditions they will face. Pogson told IFLScience that this could be done either through selective breeding or gene transfer, but that “the main thing is to identify control mechanisms.”
In Plant Cell, Pogson and Crisp report that during the stressful phase, their plants revealed discomfort by upregulating mRNAs. When the light was taken away, 87 percent of stress-related mRNAs returned to their pre-stressed state within 60 minutes, some in as little as 2.7 minutes.
Stress responses vary considerably between species, reflecting the different environments they have adapted to. Pogson told IFLScience he is in discussion with team members for ways to explore this variation at a genetic level, expanding the options on which plant breeders can draw on.
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