MAGNETOTROPISM IN PLANTS When the life activities of plants are studied in conjunction with various environmental factors, no attention is usually given to the geomagnetic field.
However, it seemed that under certain conditions the Earth's magnetic field must influence these life activities. Such an assumption was based on the presence of magnetic properties in all substances, as revealed by modern physics /1/. Consequently, the individual organelles, cells, tissues, organs, and the organism as a whole must possess magnetic fields The energy of the molecular bonds determining the chemical reactivity of substances is a manifestation of the magnetic properties of matter, and should thus change with variation in these properties. This is also reflected in the metabolism. The magnetic properties of a substance may vary according to temperature, intensity of external the magnetic field, orienta tion with respect to the lines of force of such a field, etc.
The chemical reactions between substances, accompanied with changes in their magnetic properties, generate electrical potentials, i. e., bio currents. The ensuing biocurrent will itself affect the magnetic proper ties of the matter. In the process of life activities an organism generates an electromagnetic field which is an inseparable part of the living system. It may be assumed that the magnetic properties of matter are the cause of polarity, which represents the most general feature of living matter.
Polarity both reflects and determines the definite character of the organism's metabolism. Any change in the magnetic properties of a sub stance, and consequently changes of polarity, must be reflected in the life activities of the organism.
The physical basis, determining the continuous transformations of sub stances in the organism is represented by uncompensated (asymmetric) electromagnetic forces. The continuous movement of protoplasm may be regarded as the result of asymmetric polarity.
The relationship between growth rate and intensity of plasma movement has been established. The rate of movement is strongly affected by the presence of oxygen, which, it is interesting to note, possesses marked magnetic properties. The primary value of oxygen for life processes
possibly derives from its magnetic properties. The presence of oxygen in a living system may strongly affect its electromagnetic state, altering the asymmetry of its polarity. Changes in the chemism of the metabolism may increase or decrease the asymmetry of polarity, or shift its sign toward positive or negative values. Reversal in the sign of polarity must change the direction of biochemical processes. It may be stated that the rate and character of interactions, and consequently the growth and development of organisms, will be primarily determined by the polarity.
In connection with the significance of polarity for life activities of plants we should mention the experiments on the effect of electrons upon growth of unfertilized ovaries of tomato plants.
When the experimental ovaries of the tomato plants were ready for fertilization, they were treated with electrons from radioactive phosphorus, Development of the unfertilized ovaries appears to have been induced by their exposure to negatively charged particles. The experiments revealed that the asymmetry of polarity was increased toward negative values under the effect of the electrons. This change in the asymmetric polarity indicated the conditions required for the onset of growth processes.
While setting up our experiments on the effect of geomagnetism on the life activities of plants, we intended to utilize that change in the magnetic properties of the individual components of the living system that might arise from the different orientations of the organism with respect to the direction of external magnetic fields. We therefore assumed that the maxi mum (readily detected) change in the life activities of plants will occur when the external magnetic field is applied during the initial period of life pro cesses, i. e., before the tissues assume a stable state of polarity, and before the various biochemical processes are fully developed, their rates and relationships being marked by continuous changes. With these consi derations in mind we chose plant seeds as the appropriate object of investigation.