It should be fine. The buried portion of the stem, will in time, sprout roots. As long as the plant can stop itself from falling over, a tutor or stick to keep her standing will not be needed. If she can not stay upright by herself, obviously a tutor will be needed. If you do need to tie her to a stick/tutor, remember to use a loop with plenty of room for the stem to expand as she grows. If you use a tight knot, as the plant grows and the stem expands, the knot will "strangle" the stem and possibly kill your plant. I have found wide (4-8millimetre), elastic cotton plant ties to work best for tying plants, as opposed to anything with wire.
Hope this helps.... Organoman.