nonproductive. Some of their test plants also received an aqueous soil infusion as a
source of microbial inoculum. Heating the soil infusion to 70
C, or boiling the
infusion, before administering it to the plants was used as a means of destroying
microbes naturally present in the infusion.
In their experiments, the growth of barley and oats (both family Poaceae, then
known as Gramineae) was found to be strictly dependent upon the amount of nitrates
added to the soil. However, they observed that growth of peas failed to show a
similarly dependent relationship to presence of nitrates in the soil. Chemical analysis
revealed that the crop products obtained from their pea plants contained considerably
more nitrogen than was found in the given nitrates, seeds and soil together.
Hellriegel and Wilfarth concluded that, in addition to any nitrogen present in the
soil made available to their pea plants, the peas managed to find another source from
which they were able to acquire nitrogen in abundance.
14.11.2 Hellriegel and Wilfarth’s Final Conclusions as They
Specifically Were Stated, with Computer Assisted
Translation
1. The legumes behave fundamentally different from the Gramineae with regard to
the absorption of their nitrogenation.
2. With their nitrogen requirements, the Gramineae are solely dependent on the
assimilable nitrogen compounds present in the soil and their development is
always in a direct relationship to the available nitrogen stocks of the soil.
3. In addition to soil nitrogen, the legumes also have a second source from which
they can cover their nitrogen requirements in the most extensive way or, as far as
the first source is not enough, they can supplement them.
4. This second source provides the free, elemental nitrogen in the atmosphere.
5. The legumes do not per se have the ability to assimilate the free nitrogen in the air,
but the participation of living microorganisms in the soil is absolutely necessary
for this.
6. In order to make free nitrogen available to the legumes for nutritional purposes, it
is not enough just to have any lower organisms in the soil, but it is necessary that
certain species of the latter enter into a symbiotic relationship with the former.
7. The root nodules of legumes are not to be regarded as mere reserve stores for
protein substances, but are related to the assimilation of free nitrogen.
14 Discovering the Symbiotic Nature of Microbial Life: Summarizing Milestone. . .
227
source of microbial inoculum. Heating the soil infusion to 70
C, or boiling the
infusion, before administering it to the plants was used as a means of destroying
microbes naturally present in the infusion.
In their experiments, the growth of barley and oats (both family Poaceae, then
known as Gramineae) was found to be strictly dependent upon the amount of nitrates
added to the soil. However, they observed that growth of peas failed to show a
similarly dependent relationship to presence of nitrates in the soil. Chemical analysis
revealed that the crop products obtained from their pea plants contained considerably
more nitrogen than was found in the given nitrates, seeds and soil together.
Hellriegel and Wilfarth concluded that, in addition to any nitrogen present in the
soil made available to their pea plants, the peas managed to find another source from
which they were able to acquire nitrogen in abundance.
14.11.2 Hellriegel and Wilfarth’s Final Conclusions as They
Specifically Were Stated, with Computer Assisted
Translation
1. The legumes behave fundamentally different from the Gramineae with regard to
the absorption of their nitrogenation.
2. With their nitrogen requirements, the Gramineae are solely dependent on the
assimilable nitrogen compounds present in the soil and their development is
always in a direct relationship to the available nitrogen stocks of the soil.
3. In addition to soil nitrogen, the legumes also have a second source from which
they can cover their nitrogen requirements in the most extensive way or, as far as
the first source is not enough, they can supplement them.
4. This second source provides the free, elemental nitrogen in the atmosphere.
5. The legumes do not per se have the ability to assimilate the free nitrogen in the air,
but the participation of living microorganisms in the soil is absolutely necessary
for this.
6. In order to make free nitrogen available to the legumes for nutritional purposes, it
is not enough just to have any lower organisms in the soil, but it is necessary that
certain species of the latter enter into a symbiotic relationship with the former.
7. The root nodules of legumes are not to be regarded as mere reserve stores for
protein substances, but are related to the assimilation of free nitrogen.
14 Discovering the Symbiotic Nature of Microbial Life: Summarizing Milestone. . .
227