A little background for this question. I recently bought a rhipsalis paradoxa which has been exploding with new growth. True to form, I decided to water the plant yesterday (with fertilizer in water), in the hopes of achieving even faster growth. In hindsight, this was a horrible idea as the plant stems were very turgid, happy, and the particular mix in this pot is less than ideal. I had run out of my normal fast draining, 5-1-1 type mix I use on my jungle cacti.

Sure enough, around 8-10 hours after watering I began noticing ill effects in the paradoxa stems. Some stems, if looked at through the light, have brownish splotches inside of the leaf, usually closest to the thinnest, most exterior portion of the stem. Other stems have cracks or little chunks missing where it looks like some insect has been gnawing away. I know that leaves can brown from overwatering, but this behavior seems a little extreme, expecially so shortly after watering. Is it possible that rhipsalis paradoxa cracks its stems after a lot of water for propogation purposes? Many Rhipsalis species have little bits of stem that fall off and then start a new plant. Perhaps the paradoxa has sped up this mechanism when receiving a lot of moisture?

Of course it is entirely possible that this rapid stem cracking/browning is just due to overwatering. I was wondering is someone could give me a scientific explanation why this happens in plants in general, not just in my rhipsalis. I understand tissue death in the extremities of the plant, i.e. leaf tips, when a plant is being underwatered, but I don't understand exactly why this happens in the case of overwatering. I researched this question some online, and the most common explanation is that overwatering suffocates the roots/causes root rot, which I assume results in tissue loss in the plant extremities (leaf tips) as the damaged roots can't take up water well. I have observed this phenomenon, but it usually doesn't happen so quickly after overwatering. Is it also possible that in the case of more succulent plants, cells literally explode from the plant taking up too much water?

For example, I know that very succulent plants such as lithops ¨burst¨ when taking up too much water, but I do not know whether this is from individual cells exploding or rather the plant structure as a whole becoming so turgid that the outer layer of the plant literally cracks open.

Really hoping to understand this phenomenon better from a scientific point of view. I'm attaching some pictures of my rhipsalis! Thanks in advance.