We tested pollen viability of eight species using four vital dyes, a new pe
roxidase test together with three other established methods (MTT, Baker's a
nd X-Gal), to determine their potential to differentiate fresh pollen from
pollen heated for 2 h and 24 h at 80 degrees C (killed pollen) and compared
the results with in vitro germination. We found that two of three dyes pre
viously employed to determine viability also stained killed pollen, while t
he new peroxidase test and MTT did not. We suggest that the latter two are
the best methods to test pollen viability, since they do not normally stain
either killed or aborted pollen.