The relationship of Shelford's law of tolerance with the concepts of hormesis and hyperadaptation: evolutionary aspect
Abstract
It is obvious that the limit of resistance of organisms (or entire populations) is not infinite and its width is determined by the dose range, which is called the tolerance range and is theoretically described by Shelford's tolerance law: The limiting factor for the well-being of an organism can be both the minimum and maximum impact of an environmental factor, the range between which determines the degree of tolerance of the organism to this factor. Graphically, this law is described by a bell-shaped curve, which reflects the relationship between the characteristics of the acting factors and the degree of impact on their viability, which is determined by different parameters, at different phases of their ontogenesis and at different levels of their structural and functional organization. The results of studying the dependences of the «dose-effect» type indicate the existence of such a range of doses that have a positive stimulating effect on biological objects, which is called hormesis. In our radiobiological studies, we have shown that hormesis is the result of a transitional process when there is a positive overregulation of the parameters characterizing the viability of organisms and which is called hypercompensation, which provides organisms with an increase in the initial (current) tolerance. The idea of hypercompensation formed the basis of the concept of hyperadaptation. Thus, with the obvious connection between the concepts of hormesis, the law of tolerance and the author's concept of hyperadaptation, there was a need to analyze this connection in more detail. In addition, it was important to determine how the characteristics of stability (the parameters of the Shelford's curve) change in the evolutionary process.
References
Mikhyeyev A. N. Modification of ontogenetic adaptation. Kyiv : Phytosociotsentr, 2018. 396 p. [in Russian]
Calabrese E. J. Hormesis: why it is important to toxicology and toxicologists. Environ Toxicol Chem. 2008. 27 (7). P. 1451–1474. https://doi.org/10.1897/07-541.
Selye H. Stress without distress. Moskva : Progress, 1982. 128 p. [in Russian]
Kuznetsov V. A., Zdanonich V. V., Lobachev E. A., Lukiyanov S. V. Revisiting the problem of astatic ecological optima. Biol Bull Rev. 2016. 6 (2). P. 164–176. https://doi.org/10.1134/S2079086416020043.
Cordyum E. L., Sytnyk K. M., Baranenko V. V. et al. Cellular mechanisms of adaptation of plants to adverse effects of environ-mental factors in natural conditions. Kyiv : Naukova dumka, 2003. 279 p. [in Russian]
Agathokleous E., Calabrese E. J. A global environmental health perspective and optimisation of stress. Sci Total Environ. 2020. 704. 135263. https://doi.org/10.1016/j.scitotenv.2019.135263.
