Are you try to extract all metals in a plant ? For non volatile metals like iron you can dry and ash it in a furnace, later you can use acid solution to dissolve metals into your solution. If you are looking for volatile metals like mercury, fastest way was using microwave digestion with minimal losses.
Dear Salamma, i appreciate your mail and i want to make one more request. can you please suggest an article that deals with metal recovery from plants. i need the methodology with the reference. Regards