Use of Household Enzymes to Improve Germination
One often reads in the rose hybridizing literature that the tough seed coat of the rose seed is probably weakened in Nature by the passage though the digestive system of an animal or bird when the hip is eaten. This can now be simulated by soaking the seeds in common household enzymes. That this effect does work has been determined by a published scientific experiment which is supported by my own experiment. Recently another paper has been published in a reviewed scientific journal that found that the enzyme treatment works on other seeds.
Soak the seeds (or, if the blender was used, seeds and remaining pulp) for two days in a enzyme drain cleaner solution prepared by adding about 1 tablespoon of enzyme to 150 ml (about a half cup or 5 oz) of water. The enzyme drain cleaner should be one that states on the label that it will dissolve paper or includes cellulase as one of the ingredients. From my having poor germination from seeds that were treated with a liquid enzyme drain cleaner product that contained something that turned the solution blue, I recommend solid products that do not have a color additive. After the enzyme soak, rinse the seeds using a small mesh wire kitchen strainer. The rinse is important as longer contact with the cellulase containing enzymes may kill the seed or result in the seed being put into secondary dormancy if the enzyme drain cleaner starts reacting with your germination media and produces heat (this is another reason I prefer sand as my germination media, sand is inert).
One tablet of bromelain can be substituted for the enzyme drain cleaner. Bromelain is a health food digestive enzyme. It has the advantage over the enzyme drain cleaner as one of my later experiments indicates that it does not appear to kill the seeds if the soak lasts for more than 2 days; thus, you may want to use bromelain if the seeds are from an important cross. With bromelain a 2 or 3 day soak is normally effective, but as can be seen in the link above there have been instances where soaks as long as 8 days have been successful. Another experiment that I did indicated that putting bromelain containing water in the sand that is used in the Petri dishes improved germination more than the bromelain soak alone. Bromelain tends to be expensive in health food stores. You may want to try purchasing some over the internet. A suggested starting point is: http://www.dealtime.com/xDN-Nutrition--bromelain . Some meat tenderizers also contain Bromelain; I have tested one and it did not work. I assume that the reason is that it also contained sodium salts. I have found that germinating seeds do not like sodium salts. I have treated well water; for this reason I use purchased distilled water for my seed germination set ups.
I
do not know what the mechanism is for the bromelain's action. Bromelain is
a different type of enzyme than the cellulase type. Bromelain attacks proteins (proteolytic
enzyme). I assume that the reason that overexposure to bromelain does not kill
rose seeds while overexposure to a cellulase type does is because of this
distinction. So how does a proteolytic enzyme increase the germination rate? One
possibility is that the glue (suture) that holds the 2 halves of the seed coat
together contains protein type bonds. Unfortunately, I have not been able to
find any studies that have determined the chemical composition of the glue
(suture). A second possibility is
that the bromelain hydrolyzes a dormancy stabilizing chemical (i.e. gets
rid of a chemical that keeps the seed in a dormant state). There is some
evidence to support this second possibility as studies of other seeds report
that it appears that nature produces bromelain type molecules during
germination:
Title: Changes in activity of proteolytic enzymes (BAPAases) in germinating
buckwheat and rye seeds.
Authors: Dunaevskii la E; Belozerskii M A
Published in: BIOKHIMIIA, volumn 45, pages 908-911, (1980).
Abstract: "The interrelationship between the activity of proteolytic
enzymes (BAPAases) from buckwheat and rye seeds hydrolyzing
Nalpha-benzoyl-DL-arginine-p-nitroanilide (BAPA) and the amount of the antiserum
to these enzymes necessary to obtain a certain inhibition level has been studied
at different stages of seed germination. The data obtained show that the
increase of the BAPAase activity in germinating rye seeds is due to de novo
synthesis of this enzyme. During this process antigenically identical enzyme
molecules are synthesized in roots and shoots of the developing plant."
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Title: Proteolytic enzymes in germinating rye grains.
Authors: Brijs, Kristof; Trogh, Isabel; Jones, Beme L.; Delcour, Jan A.
Authors affiliation: Laboratory of Food Chemistry, Katholieke Universiteit
Leuven, Louvain, Beig.
Published in: Cereal Chemistry, volumn 79, pages 423-428, (2002).
Abstract: "The proteolytic activities during rye (Secale cereale L. "Humbolt")
grain germination were monitored using in-soln. methods and one- and
two-dimensional PAGE with gels that contained incorporated substrate proteins.
The total proteolytic activity increased during the first three days of
germination, but not after that. The proteinase activity was measured at pH 3.8,
6.0, and 8.0 in the presence and absence of class-specific proteinase
inhibitors. This indicated that enzymes from all four proteinase classes were
present during the germination process. Germinated rye grain contained mainly
aspartic and cysteine proteinase activities that are esp. active at pH 3.8.
Serine- and metallo-proteinases were less abundant. Overall, the pattern of
hydrolysis was very similar to that obsd. during barley and wheat
germination."
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Title: Protease inhibitors of pigeonpea (Cajanus cajan ) and its wild relatives.
Authors: Pichare, M. M.;Kachole, M. S.
Published in: Physiologia Plantarum, volumn 98, pages 845-851, (1996).
Abstract: "Seed extracts from pigeonpeas and its wild relatives were
analysed for protease inhibitor activities by caseinolytic assay, and the number
of protease inhibitors determined by polyacrylamide gel electrophoresis. Besides
trypsin and chymotrypsin inhibitors, seed extracts contained weak papain
inhibitor(s) but no bromelain inhibitor. Treatment of seed extracts with
bromelain generated new active forms of trypsin inhibitors. The relative amounts
of different trypsin inhibitors and the total trypsin inhibitor activity varied
with different extraction media. Trypsin inhibitors were not detectable in
pigeonpea leaves. The profiles of trypsin and chymotrypsin inhibitors in almost
all the cultivars of pigeonpea analysed were similar; however, those in wild
relatives were quite variable."
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