This is a rather unexpected phenomenon. When seeds (of various species of plants) were exposed to ethylene gas during germination, the plants subsequently grew larger than those whose seeds were not exposed. The study concluded that the plants from the ethylene-exposed seeds were taking in more CO2, and increasing their photosynthetic rate.
phys.org
I have not tried this (e.g. placing a banana peel onto the germinating seeds in a covered cup).
Bob

Exposing plants to an unusual chemical early on may bolster their growth and help feed the world
Just like any other organism, plants can get stressed. Usually it's conditions like heat and drought that lead to this stress, and when they're stressed, plants might not grow as large or produce as much. This can be a problem for farmers, so many scientists have tried genetically modifying...
I have not tried this (e.g. placing a banana peel onto the germinating seeds in a covered cup).
Bob