Plants can sense the direction of gravity in their environment and use this information to orient their growth. However, it has been a mystery how plant cells are able to detect the direction of gravity and convert this signal into a growth response. A new study published in the journal *Nature Plants* suggests that a key part of this process involves the plant hormone auxin, which plays a role in a variety of developmental processes.

The study was led by researchers from the University of Cambridge and the University of Warwick. They found that auxin is transported within plant cells in a gravity-dependent manner. This means that auxin accumulates on the lower side of plant cells when they are placed in a vertical position. This difference in auxin concentration triggers a signalling cascade that results in the growth of new cells on the lower side of the tissue, causing the plant to bend in the direction of gravity.

The researchers believe that this mechanism allows plants to constantly adjust their growth and development in response to the changing environment. They say that this discovery could have a number of potential applications, such as the development of new growth regulators for plants or the design of materials that mimic the plant's ability to sense and respond to gravity.

"We are excited about this discovery because it provides new insights into how plants work at the cellular level," said senior author Professor Malcolm Bennett from the University of Cambridge. "It also suggests that there may be other hormones or signalling molecules that play a role in gravity sensing and response, and we are eager to explore these possibilities in future research."

The study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).