[The shell of invertebrate and plant propagules: selective permeability and barriers]

In the experiments with seeds of Ericaceae, gemmuls of Spongia, statoblasts of Bryozoa, resting eggs and ephippia of Crustacea the hypothesis on selective permeability of propagule shells was tested. It was shown that the propagules are activated and develop until the moment of destruction of shell in the solutions of phenols, formaldehyde, CuSO4, K2Cr2O7, HgCl2, Ag2SO4, AgNO3, CoCl2 and NiSO4. It means that propagule shell is impermeable for these poisons but permeable for water and oxygen. The effectiveness of barrier can be various in different species but in some cases it is very high. The development of resistance to poisons of anthropogenic origin that were not familiar to organism earlier can be considered as an example of the rule (Rasnitzyn, 1971) according which relation between environmental variability and power of regulator is shifted to the priority of regulator. Selectively permeable shell for many organisms is a common adaptation that allows colonization of land and continental waters.