In plants, where is ethylene produced?

Question

and can you tell me where brassinosteroids are produced as well?

Answer 1

Ethylene is produced in all higher plants and is produced from methionine in essentially all tissues. Production of ethylene varies with the type of tissue, ...

Answer 2

Below is the link to the cycle that forms (eventually) ethylene. It is a cell product and allows all parts of the plant to use it for the many functions that it is of value. See ethylene article in wikipedia if you would like more info. It's a little clearer than my paraphrase would be.