I have treated the roots according to Phillips and Hayman (1970). How can I preserve these roots for few weeks so that I can examine it under microscope? Should I have to remove it from the trypan stain solution?
of course it is best to examine the roots sooner than later.
You might seal them on a slide with the object glass on top. seal around with some kind of wax. But you can keep them in the staining solution and in the fridge. Nevertheless the stain will loose the clearity when kept longer like this.
I have also done similar type of work and hence I do strongly recommend the previous answers given by Madam Winkert that it would be better to do it soon rather keeping it for longer period as in spite of keeping in a freezer you might not be able to visualize the association clearly after long.
i have done something similar, i think it is better to examine immediately and if you really must preserve, it shouldnt be more than a week, because overtime the visibility of those spores on the roots tend to reduce even when properly stained.