To me it simply looks like a deficiency of some sort, but i'm no expert.... depending on where these types of leaves are appearing depends on whether or not you may have already resolved it. The leaves on the bottom of the plant may appear like this, but the top ones might not be subjected to the deficiency. I have a few leaves like that on my plants, but they are on the lower branches. I think i've also got a root disease, and I will be interested in how this thread turns out with some comments from the experts.I can't tell if this is a fungus, a toxicity, or a pH problem, or both??