When plant is cut and its cuttings are planted in the soil, after that it sprouts and take the reserve food material from the cut parts . Shoot become long but after the exhausting of food material in the cutting these shoots dried. But in some plants in the meantime root development also occur and cuttings takes its water and nutrients from the soil and prepare its own food and survived. Generally hard species not roots.   

After all type of stress the meristem cells may started the proliferation ...and in you can after severe salinity stress the meristematic cells produced only one part of plants - the shoots -, and it not can to produced the subterranean part of plant; and this is the reason of plants died -  without  the roots is absent the water flow & nutrition.

It need used the enzyme as gibberellin

Dear Geoger most pernicious possiblity should be phenolics compund accumulation in culturing media. Can you please share the picture of your culture??

I think more details are needed, but I could think of some reasons, if the cuttings where planted in the same substrate, the salt could have accumulated in it. If the cuttings where In vitro then maybe they could have phenolized through the cut tissue.

Please send more information and if possible pictures.

In short, after growth of new shoot, root might suffer from salinity or poor soil.