Can you tell us more about your tank? What type of lighting are you using? How are you fertilizing?
IME, glosso does not generally lose leaves as pictured in your photo unless it is not receiving enough light or if NO3 is limited. However, even with healthy glosso, burried leaves will turn yellow once the growth is allowed to pile up on top of itself.
It is 30G tank 3WPG lighting
CO2 at 30ppm
I am using Tom Barr's EI. 50% waterchange 1xweek, I am adding 1/4 tsp KNO3 and 1.5 ppm PO4 3x week and 7ml of traces 3xweek.
I started dosing like this one and half weeks ago.
tell me more abut the tank like how long has it been running, how long the glosso has been in there. Also, give me your tank parameters like kh, gh, po4, no3, Ca if u have it. Also, your substrate looks like some wierd gravel. What is it and do u fertilize the gravel. Its very hard to tell a deficiency from a pic without knowing the parameters in the tank. Whats your lighting cycle also. http://www.thekrib.com/Plants/Fertilizer/nutrient-deficiency.html
this may help too but it looks like u may have a few deficiencies at once, thats why I need your tank info.