When I was a child, my mother used to tell me to not 'disturb' plants at night, as they sleep just like humans do. And I, in my wilful curiosity and kind gesture, would pluck a flower for her from any of the trees and she'd chide me for hurting and causing them pain. At first, I didn't understand how something which seems almost inanimate feel any pain or needs to sleep at all. But as the years passed, and my mother's garden grew in time, I realised that trees and plants have a life and we're only sabotaging it every day for our selfish gains.

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When both the plants were under extreme stress, they started emitting ultrasonic frequencies between 20 and 100 kilohertz- not a frequency humans can pick up on without assistance but a volume that could feasibly be detected by some organisms from up to several meters away. 

The study was conducted and published on the BioRxiv database.

When the researchers cut the stems of the tomato plant, the microphone detected it emits 25 ultrasonic distress sounds for an hour or so. On the other hand, when they deprived both tomato and tobacco plants from water, tomato made louder distress calls at 35 ultrasonic distress sounds while tobacco made 11. But the interesting part is that how these plants show different levels of stress depending on the conditions they're subjected to. 

For example, starving a tomato plant makes it scream more intensely than anything else.

"These findings can alter the way we think about the plant kingdom, which has been considered to be almost silent until now," the study group summarised in its conclusion.

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