Biochemical controls: root controls (Introduction)

by David Turell , Sunday, January 12, 2025, 19:48 (23 days ago) @ David Turell

Seeking water requires root growth:

https://www.sciencedaily.com/releases/2025/01/250110143657.htm

"Plant scientists from the University of Nottingham, in collaboration with Shanghai Jiao Tong University, have identified how abscisic acid (ABA), a plant hormone known for its role in drought response, influences root growth angles in cereal crops such as rice and maize.

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"The study highlights how ABA and auxin, another key hormone, work together to shape root growth angle, providing a potential strategy to develop drought-resistant crops with improved root system architecture.

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"Plants rely on their root systems, the primary organs for interacting with soil, to actively seek water. In drought conditions, water often depletes in the topsoil and remains accessible only in the deeper subsoil layers. Abscisic acid (ABA) plays an important role in helping plants adapt to these challenging conditions. This new study gives new insights into how ABA changes root growth angles to enable plants to reach out deeper subsoils in search of water.

"The researchers discovered a new mechanism where ABA promotes the production of auxin, which enhances root gravitropism to grow them at steeper angles in response to drought. Experiments showed that plants with genetic mutations that block ABA production had shallower root angles and weaker root bending response to gravity compared to normal plants. These defects were linked to lower auxin levels in their roots. By adding auxin externally, the researchers restored normal root growth in these mutants, showing that auxin is key to this process."

Comment: Clearly a designed system to direct root growth. Plants could not have adapted to land without this mechanism available in the beginning.