Hi, I am doing experiment of lignin deposition on tomato leaves after fungi infection by phloroglucinol-HCl staining. But the problem here is that the leaves remain yellowish or blackish before staining and it is difficult to decide which was lignin or not after staining because of the remained background on leaves. So, I assume by comparing the pictures of before and after lignin staining pictures and if there seems darker in the pictures of staining (arrowing in the pictures), I assume there was lignin deposition. But I'm still confusing and if there someone who has better idea for lignin staining? and I wonder how can I clarify which is lignin since I can't remove background on leaves completely? and is there any other methods for experiment of lignin deposition? Can someone give suggestions for me? Thanks. I attached lignin staining pictures of tomato leaves.