Can an F-1 student apply for green card?

There is no clear guidance or regulation from the USCIS regarding whether a student is still under F-1 status if s/he has applied for I-485 adjustment of status. Since a student visa doesn't allow "dual intent" as in H or L visas, it seems that filing a green card application - a clear indication of immigrant intent - would terminate one's F1 status immediately. However, there have been strong arguments, precedent cases and even informal remarks from USCIS personnel that indicate one may, in fact, maintain both F1 and AOS status.

Since USCIS may issue new guidance on this matter in the future, students under this situation must be even more careful with their status issues and on- or off-campus employment opportunities. We definitely recommend applying for EAD along with your 485 application. Additionally, an advance parole (AP) is absolutely necessary if you intend to travel abroad, not only to avoid abandonment of your AOS, but also because you will have a hard time explaining to a consulate officer why you still qualify for an F1 nonimmigrant visa.

source: http://immigrationroad.com/visa/f1-student.php