Here is a pic with the buds

Looks like its suffering a bit to me. Maybe it needs a dome or something to keep its humidity up while it acclimates to being on its own?

Mid 40 temperatures are not a problem for citrus. You do not indicate where you live, so I have no idea what kind of sun you are having. I am assuming your tree you air layered was in the full sun. For a week or two I would keep you new tree outside in partial sun until you note new growth, before moving to full sun. When fully established I would start pruning to shape. Al

Mid forties is not a problem for citrus in a container, if you don't mind them barely growing or slowly declining depending on the variety if above ground...... Some potted citrus can not tolerate those kinds of temps and cold roots while others can pretty much hold their own until its warms up..

If your tree is in a porous mix with those kinds of temps, all the more power. If it's in a fine mix that takes its time to dry out, it's a risk.

For me, I don't mind them slowing down or looking anything but perfect for only a short time...I will eventually bring them in at night when I start to see them react to the cold..

Some of my citrus I refuse to let see temps drop below 55 if I want to keep them actively growing, the ones I have a sof spot for, my favorite ones.

if you leave your trees exposed to those kind of cold temps without adjusting them to indoors as you are doing, bringing them into a warm environement will shock them and cause leaf drop or other issues.

All that being said, this is what I would do..

**I would bring my trees in at night if temps drop below 50 and bring them back out on those warm days into part sun** until you bring your trees in for good..

I would keep the roots warm since it's just getting started and in a pot, not the warm ground although the outside ambient air would be cold...

Thank you guys for your responses. I live in Indiana. It is a Washington naval orange. I don't want too stress it out. And I'm hoping the buds don't fall off, since it was the only party of the tree that actually flowered and buded. So to sum it up, leave it in partial shade and bring it in at night, right? Now that it is potted, which I just did 2-days ago, it will require more humidity? Or is it ok to keep it in the same environment as the mother plant and other citrus? I'll be bringing it in soon because the good weather will be gone in a week or two. Ant recommendations on the grow lights? Don't have a window with adequate lighting.

You don't need humidity for it to do well, although it would love it. Treat it the way you do the mother plant if you find the mother plant has been well under your care)