Calcium signals temporarily reduce roots’ response to a growth hormone
A peer-reviewed experiment in Arabidopsis links preceding calcium signals to a weaker response to auxin, a plant growth hormone. Electrical changes, gene activity and reversible root-growth inhibition formed different parts of the observed response. The researchers identified a candidate molecular link, while the experiments leave agricultural performance and broader effects across plant species untested.
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Light controlled calcium in root cells
In a peer-reviewed experiment, researchers altered calcium signals in Arabidopsis, a small flowering plant widely used in laboratory research. They equipped root cells with a light-sensitive channel that allowed calcium to enter when activated. This let the team impose signals and then apply auxin, a hormone involved in plant growth. Measurements of cell voltage and calcium showed that preceding calcium stimulation weakened the rapid response to the externally supplied hormone.[1]
The response recovered after a pause
A comparison channel changed membrane voltage without producing the same suppression, helping distinguish the calcium response from an electrical change alone. Cold and glutamate, a chemical associated with wound signalling, also elicited calcium signals followed by a weaker auxin response. In those experiments, sensitivity recovered after a pause. Repeated auxin exposure itself showed a similar temporary attenuation, consistent with feedback in which the hormone’s calcium signal reduces responsiveness to the next stimulus.[1]
Gene activity and growth also changed
Longer calcium stimulation altered auxin-responsive gene activity and reversibly inhibited root growth, with reduced cell division and elongation. The researchers identified a candidate connection between CaM7, a calcium-sensing protein, and CNGC14, a channel involved in calcium entry. The paper presents this molecular module as a likely contributor to the regulation. The work concerns cellular responses in the experimental plant and does not establish crop yields or demonstrate the same effects across other plant species.[1]
