THE TOPOGRAPHICAL TETRAZOLIUM METHOD FOR DETER-
MINING THE GERMINATING CAPACITY OF SEEDS -
Received July 14, 1948
In 1942 the author published the so-called tetrazolium method for de-
termination of the germinability of seeds (3).
the reduction in germinability of the seeds due to a gradual dying-off of
the embryo (2).
The topographical spread of necrosis of embryo tissues
can be demonstrated by means of 2,3,5-triphenyl-tetrazolium-chloride.
This compound is colorless but is reduced (hydrated) into the stable but
nondiffusible red formazan by living cells (3).
tetrazolium is a definite indication of its viability because necrotic cells
remain uncolored. By means of extensive experiments conducted over a
period of years, the procedure has been perfected to demonstrate which
parts of the embryo are at least sufficiently viable to make germination
The recent publication of R. H. PORTER, MARY DURRELL, and H. J.
(1) concerning the topographical tetrazolium method does not,
however, present the method correctly in relation to several essential points.
In order to correct these errors, the present author submits a short descrip-
tion of his method (3).
Use of the tetrazolium method merely involves preparation of the em-
bryo of various species of seeds in such a way that all those parts which
are decisive in the estimation of germinability be made visible.
cereals the anterior face of the embryo must be visible.
carp is impermeable and opaque in most cereals the embryo must be re-
moved from the kernel with a lance-like scalpel or dissecting needle.
cept in maize, a longitudinal section through the center of the embryo is
not adequate because the lateral root primordia remain invisible.
in oats is the pericarp sufficiently transparent to obviate excision of the
The embryo of maize, however, possesses a simple root primor-
dium, and the lateral root primordia (secondary radicles) in the meso-
cotyl are uniformly distributed.
In this instance a longitudinal section
provides the best preparation (5).
The presoaking of the seeds in water
is necessary only to facilitate the removal of the embryo.
germination is neither necessary nor significant for the test because even
non-after-ripened cereals can reduce tetrazolium
described below, the cross-sectioned grains of oats are placed in tetrazolium
solution without pre-soaking.
Only in the case of maize is the staining of
the scutellum important in relation to germinability.
This method is based upon
Coloration of a cell by
Since the peri-
According to the method
This response of
Ueber Keimpotenz und labile Keimtendenz bei Pflan-
zensamen, insbesondere bei Getreidefriichten.
Bestehen der Landw. Hochschule Hohenheim.
7. RODEWALD, H.
Untersuchungen iiber die Fehler der Samenpriifungen.
Arbeit. Deutsch. Landw.-Gesellsch. Heft. 101.
Festschrift z. 100