The work was undertaken with objectives to ratify and determine the possibility to
use the pH of seed exudate using the bulk system for corn seeds. It was used 32 seed lots. Two
studies were conducted. The first one consisted of evaluating the seed individually through the pH
of seed exudate test using sodium carbonate and phenolphthalein solution (IS) at different
concentrations and imbibition time. The second study was based on evaluating the seed as a bulk
system using two ways: (i) determining the time necessary to change the color of the seed exudate
when the IS was added with the imbibition water, (ii) determining the quantity of the SI necessary
to change the color of the seeds exudate after a time of imbibition. For the studies the seeds were
cutted through the embryo. The tests conducted on normal seeds were the standard germination
and vigor (cold test) which were correlated with pH of seed exudate test. Based on the result the
following conclusions were taken: it is possible to determine corn seed viability through pH of
bulk seed exudate, but presents an average relationship with cold test; the process to determine
corn seed viability using the pH of individual seed exudate performs better using 20 min. of
imbibition and 8g of Na2CO3 liter-1 of water + phenolphthalein at 0.5%; and it is possible to
determine through the pH of bulk seed exudate test that low quality seed lots require 0.7ml of the
IS to change color after 25 min. of imbibition.