soybean extract for germination

General Discussion
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Title: Germination improvement by means of soybean extract.

Author: Bucksteeg, Wilhelm.

Published in: Nachrbl. deut. Pflanzenschutzdienst (1938), 18, pages 87-88.

Abstract: “Soybean ext. was prepd. by digesting 1 part soybeans, freed of the shell and bitter principle, with 4 parts H2O at 60 for 24 hrs. The ext. contained 3.5-4.0% dry matter; the pH was 6.6. The ext. was applied to the soil at the dosage of 1.25 l. per sq. m., usually after seeding. Control plots were treated with corresponding quantities of H2O. In 14 days the improved quality of seedlings in the treated plots was definitely noted by virtue of larger size and deeper green color. Furthermore, the no. of germinated seeds per unit area of treated plots was considerably larger than in the controls, e. g., the increase for roses was 70-100%; for Rhodotypus kerrioides 45%; for Acer palmatum 75%; for Juniperus communis 70%; and for Symphoricarpus racemosus 45%. There was also some indication of greater resistance to disease and to effects of bad weather. The expts. are to be continued on a larger scale.”

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Interesting observation. I assume they actually meant the hulls, (thin layer around the seed) not shells like on peanuts, nor the pods of the beans.

A colleague of mine Philip Nordin in the early 1980s showed that most of the water leachable material is pinitol, a polyol related to inositol and used as an osmotic protectant in the root nodules of soybeans. So far there has been very little evidence that it has any big role during germination, though I suspected at the time that it is a recognition signal for symbiotic bacteria and a recent paper shows that in another legume it actually does play an important role as a bacterial nutrient.

At 60 (C ?) there would be other stuff coming out but most proteins would be denatured. That’s related to making soy milk and tofu, if the beans are ground up, not leached intact.