Japanese scientists from Saitama University have unraveled the mystery of how plants communicate danger signals, showcasing the phenomenon in a video. Since the 1980s, scientists knew that plants could warn each other of threats, but the precise mechanism remained elusive. In a study published in Nature Communications, molecular biologists Yuri Aratani and Takuya Uemura demonstrated the intricate communication network among plants when detecting danger.
Set-up and Experimentation
To explore plant communication, the scientists conducted experiments using caterpillars on leaves from tomato plants and Arabidopsis thaliana, a common weed. The engineered Arabidopsis plant featured a biosensor that fluoresced green upon detecting an influx of calcium ions. The researchers concentrated compounds in a plastic bottle, pumping them onto the recipient plant to analyse their impact.
Undamaged Plants Response
The undamaged plants responded to messages clearly from their injured neighbors, showcasing calcium signaling across their extended leaves. Compounds Z-3-HAL and E-2-HAL were found to induce calcium signals in Arabidopsis through airborne compounds. The researchers identified guard cells, mesophyll cells, and epidermal cells as the initial responders to danger cues.
Cell-Specific Responses
Using Arabidopsis plants with fluorescent sensors in specific cells, the team observed that guard cells promptly generated calcium signals when exposed to Z-3-HAL, followed by mesophyll cells. Significantly, pre-treating plants with a phytohormone that closes stomata reduced calcium signaling, indicating that stomata function as the plant's 'nostrils' in this communication network.
Scientific Insight
Masatsugu Toyota, a senior author of the study, expressed excitement about unveiling the intricate story of how plants respond to airborne warning messages. He emphasized the pivotal role of this ethereal communication network, hidden from view, in safeguarding neighboring plants from imminent threats promptly.
