Researchers from the Hebrew University of Jerusalem believe an early-morning surge in stomatal activity may be key to developing crops tolerant to heatwaves and drought
The impact of this summer’s widespread drought across Europe is likely to be felt beyond the initial dried-out soils and lower crop yields, highlighting as it did the urgent need for action to protect food security.
When it comes to breeding, efforts to develop varieties that can survive weather extremes are continuous, and new research from the Hebrew University of Jerusalem may shed further light on how that goal will be achieved.
Published in Plant Science, the study, led by Dr Sanbon Chaka Gosa and Prof Menachem Moshelion from the university’s faculty of agriculture, found that when tomato plants open and close their leaf pores may be just as important as how many they possess.
“The team combined years of field performance data with advanced greenhouse phenotyping to compare drought response across genetically diverse tomato lines,” the university stated. “They found that the strongest-performing plants consistently displayed an early-morning surge in stomatal activity — opening their stomata when sunlight was already strong but before heat and dry air greatly increased water loss.”
The researchers labelled this the “golden hour”, the period when plants maximise photosynthesis while minimising unnecessary water loss.
“Plants don’t simply save water during drought – they manage it strategically,” said Moshelion. “Understanding these dynamic patterns gives breeders entirely new traits to target when developing crops that can thrive under increasingly unpredictable climate conditions.”
The best-performing lines also recovered quicker after drought, maintaining high biomass and water-use efficiency. Once water returned, the plants that utilised more water in favourable conditions were actually the ones that often recovered more quickly.
The researchers concluded that although high-performing plants tended to have more stomata on the underside of their leaves, anatomy alone could not predict drought resilience.
“Our work shows that a plant’s daily rhythm matters,” said Gosa. “By measuring how plants respond continuously rather than at a single moment, we can identify resilient varieties much earlier and with far greater precision.”
The approach could potentially slash the time needed to identify promising tomato varieties, the researchers said, “helping breeders develop plants that can better withstand drought while maintaining productivity”, and they believe the same strategy can work with other crops beyond tomatoes.
