What an intense and suspenseful story, @ipexito. Nicely told. A tragic ending!
Here's a tip for you: Regardless of the type of story or the genre, readers are hungry for relatable characters. It is only toward the very end of the story that you introduce this character, which instantly brings the story to life:
As the machines approached this area, the engineers in charge of controlling the machines also approached. One of them, Philip, looked at these plants with curiosity. Philip had been away from home for days. He missed his home and his family very much. The plants reminded him of his home garden. He and his son had planted various plants in the garden, his wife would try to grow vegetables like tomatoes and cucumbers for breakfast, and sometimes they would eat the crops for breakfast or salads. For a moment Philip forgot that he was on an alien planet in space and became emotional.
If you opened the story with Philip's experience, readers would be even more interested all the way through to learn what befalls him in the excursion to the planet!
Thanks for the suggestion, actually there is no protagonist in this story, there is only Philip, a character who triggers events. There had to be a reason for Philip to touch the plant and his family came to his mind :) The earthquakes are caused by the promethium being dug up and damaging the plant monster, but with a second warning the monster comes alive and that's what happens.