org-startup-with-beamer-mode

org-startup-with-beamer-mode is a variable defined in `org.el'.
Its value is

nil

Documentation:
Non-nil means turn on `org-beamer-mode' on startup.
This can also be configured on a per-file basis by adding one of
the following lines anywhere in the buffer:

#+STARTUP: beamer

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.