Re: what is the best way to test the effects of nicotene on plants?

You can dilute tobacco in water. The problem with diluting tobacco in water is 
that it will dissolve a variety of other chemicals that might also affect plant 
growth. You also have no exact knowledge of the actual nicotine concentration.

You can buy nicotine sulfate, which is used as insecticide. You may be able to 
find nicotine sulfate at a garden center. Black Leaf 40 is one trade name for 
nicotine sulfate. Be very careful when using nicotine sulfate because it is 
very toxic. Wear rubber gloves and safety googles and apply in a well-
ventilated area. Be sure to have a parent or responsible adult help you. 

Injecting it would be very difficult and would probably cause a lot of damage 
to the plant. Spraying it on the plant would probably be the easiest 
application method. Remember that the function of nicotine in a plant is to 
protect against insects or animals that attempt to eat the plant. That's why it 
is used as an insesticide. Therefore, nicotine is not extremely toxic to 
plants, but can harm plants at a high enough concentration. 

The last two websites discuss how leaf wounding, as when animals feed on a 
tobacco plant, trigger the plant to produce more nicotine to defend itself.


References


Black Leaf 40


VENDORS OF MICROBIAL AND BOTANICAL INSECTICIDES AND INSECT MONITORING 
DEVICES


Ecological consequences of jasmonate-induced responses for plants in native 
populations


Nicotine