Makes you wonder why the dramatic leaf loss if the roots were okay. I've never grown Ags either hydro or semi-hydro but would imagine that would be too much water for them. With mine (in soil) I've found they are good with a bit of drying out before being watered and the soil being kept just damp. The stem stores reserves for the plant so it should reshoot if conditions are kept right. It doesn't look wrinkled up so it should be okay.

i root tips of ags in water and then xfer to perlite and then to light mix. they take anywhere from 4-8 or even 10 weeks to root. when kept on heat mat and tented for high humidity they root much faster...about 5-6wks.

but yours already had roots, so putting it in water would rot them...

from my experience with rooting - this stem will just rot away unless you put it on a heat mat and keep it on it for sev months tented +hot+moist. but even then it might still rot without leaves. ags are very slow growers, by the way. with 1 leaf it might take 2 months to grow a 2nd one.

also the pot is way too big - it should be half of that diameter. cold soil = root rot for ags.