| I don't know , i think that was supposed to hint to the fact that the toxin is released when exposed to certain emotions , like fear , anger , hostility . I know it's a bit metaphysical and fantastical but maybe not that much of a stretch , because plants are affected by the chemicals people release ( at least in the film they were ) , much like a dog can sense people's emotions because we give off pheromones depending on our emotional state . That's why a dog in the presence of an anxious person will become nervous themselves . In the film , the masses were giving off depressing and nihilistic emotions , thereby creating a hostile , threatening environment for the plant life , so they reacted by releasing the toxin , i'm thinking it was a defense mechanism , a survival instinct . Some people have said that the plant's were releasing the toxin because we were destroying the planet , i think it was because of the aforementioned emotional atmosphere that had been created . Spoilers That's why i feel Elliot , his wife and his friend's daughter were never in any real danger of being affected by the toxin, they were all optimistic , caring , and loving towards other people , they didn't release the emotions / chemicals that would cause the plants to respond . To say love conquered all in the end is a bit short sighted , it was their positive inclinations that neutralized the threat , it stabilized the reactions the plant were experiencing . |