Thinks Chetna Ugale for your information, so now I can use saffranin or methyl green to color my pollen after acetolysis.

Sometimes pollen color after acetolysis also depending upon the exine thickness. For instance echinate pollen (with thick exine) commonly becames very dark after acetolysis, in that case a chlorination is necesary to get more detailes analysis.

Pollen color after acetolysis usually do not remain the same. However using Glycerin jelly with saffranin gives them an added red coloration. But know it that add more may obstruct some of the important features such as the ornamentation

.  

You can also use fuchsin instead of safranin.

I argue; to get a detailed picture of the pollen grains, If staining can reduce the results of the analysis, how about using a contrasting colored lenses as background when observed under a microscope.

Syafrizal - Reinberg illumination can be done to illuminate some pollen morphology. However, this technique requires low magnification.

Abderrahim - There are many ways to stain your pollen after acetolysis, depending what color you want, e.g., brown, blue, red, violet, etc. My advice is to use about ½ the amount of stain that the formula calls for so you don't overstrain.