“I have been able to prove that magneto-inductive forces act only on free ions…The action of alternat[ing] magnetic fields possessing enough strength, is an established reality and lends itself to practical biological manifestations… a modification takes place in the normal outlines of the embryos, which give place to mutations whose existence can be verified.” - Alberto Pirovano, 1950 (source)
Did the plant breeder known as the 'Italian Michurin' develop a relatively safe, DIY method of pollen irradiation using magnetic fields?
In the process of looking at references on Michurin, I came across the name Alberto Pirovano (1884-1973). Pirovano was the son of a grape breeder and a self taught electrical experimenter. He released several grape cultivars cultivars which are still grown widely such as ‘Italia’ used in pisco production in Peru (source). He was an early pioneer in the field of mutation breeding, among the first wave of experimenters to apply electromagnetic fields to seeds and pollen in the in the 19-teens and twenties prior to the burgeoning of mutation breeding as a field (source).
What similarities did Pirovano have to become known as the “Italian Michurin?” Like Michurin, his research interests had to do with “the plasticity of species,” but he did not work with grafting (source). Like Michurin, Pirovano also claimed that exposing pollen to electromagnetic fields promotes the success of distant hybridization, but Michurin used electrostatic fields for this purpose (source). Like Michurin, a version of his ideas were adopted by the fascist regime of his country and became associated with “Lysenkoism” (source). Could there have been a baby lost in the bathwater of politicized science as with Michurin? While Pirovano’s theories of heredity and electrogenetics can be largely dismissed in light of modern biology, what can be learned from the plant breeder who spent decades treating pollen and growing out the seeds?
Pirovano published a 300 page text in 1922 called the “Electric mutation of botanical species.” Later in the 60s it was translated to English and published as “the Electrogenetics of Alberto Pirovano” but didn’t remain in print long. The original Italian version of the text is available online. It’s written in a form of Italian that is cumbersome for native Italian speakers today. It includes about 100 diagrams of machines that Pirovano built for pollen treatment.
In 1925, Flint published a critical review of Pirvano’s book in English in the Journal of Heredity (source). Here are some relevant sections:
“These methods are all homogenous in that they all involve the electrical treatment of pollen prior to pollination yet they offer a lamentable diversity in the particular nature of the electrical treatment, since use is made of radio-active materials, x-rays, ultra-violet rays, electrolytic action, magnetism and high tension electric current, with diverse variations and combinations.”
The criticisms of Pirovano are primarily due to his not having done properly experimentally controlled trials, using multiple variables at once. The other criticism is that the variation Pirovano observed could be part of the normal range of variation of a species, or a result of hybridization. Flint continues:
“…the types of variation obtained, and attributed by Pirovano to the influence of the electrical agencies, are of the sort ordinarily associated with hybridization, while the frequency of these variations is not clearly established as having been modified…The plants used in these experiments were all annuals, and included species of Papaver, Cheiranthus, Helianthus, Althea, Cucurbita, Lunaria, Solanum, Brassica, and Pisum. No experimental data for any of these plants appears sufficiently convincing to establish the fact of abnormal variation, let alone the definite association of such variations with electrical influences.” (source)
All of these same criticisms of Pirovano are rehashed in 21st century references such in the 2017 book “The Lysenko Controversy as a Global Phenomenon: Vol II” (source). A few paragraphs from Flint’s 1925 review made their way into that book, including this part:
“Pirovano’s data and illustrations were therefore misleading since they failed to indicate the true range of variability associated with the use of normal pollen. Furthermore, the types of variation obtained—and attributed to the influence of experimental treatments—were of the sort ordinarily associated with hybridization, and there were no data on the changes in the frequency of these variations under experimental conditions.”
The above section is not cited as Flint’s conclusion, and reads as the conclusion of the authors. There probably isn’t much to take issue with regarding the lack of experimental control or the dismissal of electrogenetic theory. What strikes me as odd and inconsistent, however, is to say that all of the phenotypic variation that Pirovano observed was natural variation. Pirovano frequently exposed pollen to multiple sources of irradiation as Flint notes, but did so because he was more interested in induced plasticity than teasing out the specific effects of field type and intensity for each species. Flint can’t be faulted for assuming the possibility that all of the variation that Pirovano witnessed was due to already existing or to hybrid variation, because mutation breeding as a field did not exist in 1925. It wasn’t until the ensuing decades of the 30s-60s that mutation breeding as a field really took off. Since mutation breeding has become widely known, the criticism that Pirovano was working with natural variation would not seem to make as much sense as it did in 1925. Pirovano spent several decades exposing pollen to a huge range of electromagnetic fields, including ionizing radiation.
“First, Pirovano combined different kinds of electrical treatment—radioactive materials, X-rays, UV rays, electrolytic action, magnetism and high-tension electric current without specifying the alleged mutagen agent (source).”
How is it possible in 2017 to criticize Pirovano for using too many variables at once— including intense ones like X-rays and radioactive materials—and in the previous paragraph say that he wasn’t inducing any novel variation just working with naturally occurring variation?
Pirovano’s last publication that I could find is a short article from 1950 called “The Institute of Fruit-culture and Electrogenetics in Rome” (source). It was translated into English, indeed it’s the only writing by Pirovano in English that I have seen. By this time, Pirovano was approaching five decades of work, and for the last two of those the field of mutation breeding as a field had been developing internationally. The theory of electrogenetics however had not been developing alongside mutation breeding, and electrogenetics stopped being a term of use. The 1950 article depicts some of the variation that Pirovano achieved:
Pirovano published his book on electric mutation in 1922. In 1927 the Institute of Electrogenetics and Fruit-culture was formed in Rome. Nearly 30 years later the institute published an article summarizing their work. Its possible that the criticisms regarding a lack of experimental controls in by commentators such as Flint in 1925 caused Pirovano to make more careful experimental designs in his ensuing decades of work at the Institute of Fruit-culture and Electrogenetics. The 1950 article depicts some interesting variation, but by far the most interesting thing was Pirovano’s excitement about the effects strong alternating magnetic fields on pollen. Pirovano was already discussing the magnetic field treatment of pollen, in addition to ionizing radiation, in his 1922 book on electric mutation. Yet the field of mutation breeding subsequently developed around the use of only the ionizing forms of radiation such x-rays and gamma rays (chemical mutagens are also used). Ionizing radiation directly damages DNA, but magnetic fields (even fairly intense alternating ones) are non-ionizing. By the time of the 1950 article, pollen treatment with ionizing radiation was well known by scientists and in use for some time. Indeed, we still use it today, yet magnetic field treatment of pollen is unheard of. Is the reason simply because ionizing radiation damages DNA and therefore works, while magnetic treatment does not, so was forgotten? Perhaps, but why after 4+ decades of work did Pirovano still insist that magnetic irradiation was more useful (source), while other methods he worked with became commonplace? According to Pirovano, magnetic irradiation is more forgiving, it doesn’t reduce pollen viability as ionizing radiation can, but also because it promotes the likelihood of distant hybridization. With ionizing radiation, the proper strength to induce variation and not kill the pollen is a narrow window. Also, a person can do magnetic irradiation at home but ionizing methods would be more difficult and require more safety precaution.
After looking at this 1950 article, I found the link for Pirovano’s book in Italian. It’s interesting to scroll through and look at the diagrams but you can’t get much out of it, and an old copy of the English translation currently sells for around 1000$. I sent the link of Pirovano’s book to a friend of mine in Italy named Paolo who is a plant breeder as well as electronics experimenter. He got back to me a couple weeks later, saying it was a difficult form of Italian to understand, but he had made it through the book. Paolo stated that the most salient thing to him was the use of fairly strong rapidly-alternating magnetic fields to irradiate pollen. Paolo described to me how to replicate Pirovano’s magnetic irradiation setup with a greater efficiency using modern methods. Fairly intense variable magnetic fields ranging in frequency from 10s-100s Hz are required to replicate the magnetic irradiation experiments. It is most easily achieved using a spinning rotor containing neodymium magnets of alternating polarities. Something akin to this:
Is Pirovano’s magnetic irradiation legit? Until someone replicates it, we can’t say for sure. The threads of the case merit pulling on, but until then, is there anything in the scientific literature indicating a potential for magnetic fields to induce genome instability or transposon activity?
Here is one interesting reference:
“The research group was the first in the world to describe genomic instability caused by an extremely low-frequency magnetic field, and this can be regarded as their most significant achievement so far. Genomic instability is a phenomenon that was first observed under ionising radiation, changing our understanding of the basic concepts of radiation biology. According to traditional radiation biology, possible mutations in a cell exposed to radiation are inherited by future generations of cells as such…However, more recent observations in radiation biology show that offspring cells inherit an increased tendency for mutations, meaning that there will be genetic variation in future generations of cells. This phenomenon is known as genomic instability, and recent findings now show that it can also be caused by extremely low-frequency magnetic fields.” (source)
Pirovano’s thinking, as written about in "The Lysenko Controversy as a Global Phenomenon Vol. II,” was that the electromagnetic field treatment of pollen functioned to “shake the stable arrangement of atoms” and thus mutate the resulting plant:
“According to Pirovano, the stability of the species could only be explained by the stability in the molecular structure of the germplasm. A direct action could thus bring disorder (and variation) in the atomic composition of the plasm. This action, which he called jonolisi, consisted in the application of a variable electromagnetic field directly to the pollen. The jonolisi was supposed to shake the stable arrangement of atoms, if the result was one of the few life-compatible, to give birth to a mutated plant.”
The destabilization of the organism can of course be caused by DNA damage in the case of ionizing radiation. In the case of magnetic irradiation, the induced plasticity can potentially occur due to the mobilization of transposons in the pollen, a less direct way of altering the genetic structure. Pollen is inherently more susceptible to this as it “undergoes dynamic epigenetic regulation of expression from transposable elements” and “growing evidence indicates expression of TEs (transposable elements) is more dynamic in pollen than other tissues” (source). Perhaps the magnetic irradiation of pollen is a legit technique and does in fact result in the plasticity that Pirovano was so focused on?
*Some other sources:
Magnetic Field Exposure Stimulates Transposition through the Induction of DnaK/J Synthesis (source)
Genomic instability induced by 50 Hz magnetic fields is a dynamically evolving process not blocked by antioxidant treatment (source)
Evidence of Changes in Genomic Location of Transposable Elements in Drosophila Melanogaster Flies Exposed to Static Magnetic Fields (source)
Amazing! Someone needs to try this or we will never know for sure.