I am a student from Roumania looking for some answers about the world
around.Just other day I entered a discussion regarding the capacity of plant to
reason,to think.

You may have a problem here because of the subtleties of translation.
Basically, plants cannot think or reason because they do not have a brain or
anything remotely resembling nerve tissue. The various processes carried on by
plants are governed by hormones & other chemicals which are carried from one
part of the plant to another through the vascular system.
You may have heard that if you have a field of a certain species of plant, and
you place some noxious insects on one of the plants, all of the plants in the
field will produce a defensive chemical. There is no conscious thought
involved; it is the result of a chemical transmission. However, according to
the Oxford English Dictionary definition of communication (British English),
the plants are communicating. According to Merriam-Webster (the American
standard dictionary), they are not.
There are no scientific arguments whatever which will uphold the belief that
plants think.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)