Calcium ion is a versatile second messenger for diverse cell signaling in response to developmental and environmental cues. The specificity of Ca²⁺-mediated signaling is defined by stimulus-elicited Ca²⁺ signature and downstream decoding processes. Here, an Aequorin-based luminescence recording system was developed for monitoring Ca²⁺ in response to various stimuli in Arabidopsis. With the simple, highly sensitive, and robust Ca²⁺ recording, this system revealed stimulus- and tissue-specific Ca²⁺ signatures in seedlings. Cellular Ca²⁺ dynamics and relationship to Aequorin-based Ca²⁺ recording were explored using a GFP-based Ca²⁺ indicator, which suggested that a synchronous cellular Ca²⁺ signal is responsible for cold-induced Ca²⁺ response in seedlings, whereas asynchronous Ca²⁺ oscillation contributes to osmotic stress-induced Ca²⁺ increase in seedlings. The optimized recording system would be a powerful tool for the identification and characterization of novel components in Ca²⁺-mediated stress-signaling pathways.

An Aequorin-based Film Adhesive Seedling (FAS) Ca²⁺ recording system was developed for monitoring Ca²⁺ in response to various stimuli in Arabidopsis. This system revealed stimulus- and tissue-specific Ca²⁺ signatures in seedlings with a simple, sensitive, and robust Ca²⁺ recording.