My advice will be that you refer Doil Choi, South Korea papers on Plant-pathogen interaction using Chilli as system for his wonderful work.

I'd suggest aniline blue and phloroglucinol staining in the first instance.

Lignin deposition can easy be observed by Phloroglucinol HCl staining, and potassium dichromate staining methods. Callose deposition can be observed by toludine blue staining. In other case, you can detect both by auto florescence on a UV microscope. That is more reliable.    

thank you one and all.. i will look into all the possibilities.....

You can follow the NREL standard protocol to determine the biomass composition (lignin, cellulose, and hemicellulose)

http://www.nrel.gov/biomass/analytical_procedures.html

In addition, use acetyl bromide method for lignin determination

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0110000

thank you......