I have calla lilies in pots
I have calla lilies in pots - I have one where the bloom is not opening all the way and the pod inside is very large and drooping over. Can I plant these pods in the bloom for more flowers or is this a form of root rot?
The pod is actually the flowers, hundreds of very tiny flowers. The white part is a kind of bract, which are modified leaves. While under very special conditions the flowers might become fertilized and produce seed, this is not likely to happen under home conditions. So no, you can't plant the "pod' and grow new plants. You can grow new plants by separating and planting the rhizomes, what some people think are bulbs.
Here is some information on drooping callas: https://www.gardeningknowhow.com/ornamental/bulbs/calla-lily/drooping-calla-lilies.htm