I do not see a pic of what your specifically asking about.
However, reading your diary
Your plant looks overwatered to me
Puffy/speed bumpy leaves curling down...
If your showing something you think is a deficiency... my guess... you have over watered and rotted the root hairs...
Plants need dry time as much or more than they need wet time....
Try letting them dry out more between waterings... but know that it's going to take time to correct the problem...
Best of luck