Research Reveals Plant Roots Change Shape and Branch Out for Water

Nov 18, 2022

Researchers have discovered how plant roots adapt their shape to maximise their uptake of water, pausing branching when they lose contact with water and only resuming once they reconnect with moisture, ensuring they can survive even in the driest conditions.

Plant scientists from the University of Nottingham have discovered a novel water sensing mechanism that they have called ‘Hydro-Signalling’, which shows how hormone movement is linked with water fluxes. The findings have been published today in Science.

Water is the rate-limiting molecule for life on earth. The devastating impact of climate change is enhancing the effects of water stress on global agriculture. Climate change is causing rainfall patterns to become more erratic, impacting rain-fed crops in particular.

Roots play a critical role to reduce the impact of water stress on plants by adapting their shape (such as branching or growing deeper) to secure more water. Discovering how plant roots sense and adapt to water stress is vital importance for helping ‘future proof’ crops to enhance their climate resilience.

Using X-ray micro-CT imaging researchers were able to reveal that roots alter their shape in response to external moisture availability by linking the movement of water with plant hormone signals that control root branching.

The study provides critical information about the key genes and processes controlling root branching in response to limited water availability, helping scientists design novel approaches to manipulate root architecture to enhance water capture and yield in crops.

Dr. Poonam Mehra, postdoctoral fellow, from the School of Biosciences is one of the lead authors and explains: “When roots are in contact with moisture, a key hormone signal (auxin) moves inwards with water, triggering new root branches. However, when roots lose contact with moisture, they rely on internal water sources that mobilises another hormone signal (ABA) outwards, which acts to block the inwards movement of the branching signal. This simple, yet elegant mechanism enables plant roots to fine tune their shape to local conditions and optimize foraging.”

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Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.