The effect of zinc contamination from electricity pylons. Contrasting patterns of evolution in five grass species

Abstract

SUMMARY Samples of 8-35 individuals of Agrostis capillaris, A. stolonifera, Anthoxanthutn odoratum, Deschampsia cespitosaand Eestuca ovina were collected from zinc-contaminated soils beneath electricity pylons erected in North Wales and Lancashire between 1956 and 1970. Their zinc tolerance was assessed, as was that of two individuals of the same species collected from adjacent uncontaminated soils. Five soil samples from beneath each pylon were collected for evaluating total and extractable soil zinc, soil pH, and soil organic matter.Some degree of zinc tolerance was detected in all five species, suggesting that evolution of tolerance has taken place relatively rapidly, particularly in A. capillaris, D. cespitosa, and Anthoxanthum odoratum. However, tolerant individuals of all species were not found beneath all pylons even when the species was present in the surrounding vegetation, l^his confirms and extends to other species previous findings in A. capillaris, that the gene or genes necessary for the evolution of tolerance are not universally present within species.

Maternal transmission of adaptive modifications in salt‐treated Sorghum bicolor: a first stage in ecotypic differentiation?

“…Ecotype formation seems to be a rapid and successful process (e.g. Al-Hiyaly et al, 1990) which is not always related to any genetic potential for tolerance present in the initial population (Gartside & McNeilly, 1974 ;Ashraf et al, 1986). In Chloris gayana, salinity tolerance was not increased by five successive generations of artificial selection towards the most tolerant individuals (Malkin & Waisel, 1986).…”

“…Ecotypes adapted to a new environment are not emerging from all the populations spontaneously present in the modified ecosystem (Al-Hiyaly et al, 1990), and their differentiation is not always related to any genetic potential for tolerance (see the Introduction section). The link between transmissibility and embryo imprinting suggests that the ability for ecotype differentiation might depend on the level of homeostasis in the maternal environment during embryo maturation.…”

Global urban signatures of phenotypic change in animal and plant populations

“…Heterogeneity can refer to heterogeneity in space or time. Novel disturbances require novel adaptations, for example, rapid evolution of zinc tolerance (42). Social interactions refer to direct or intentional results of human agency.…”

Rapid response to artificial selection on flower size in Phlox

“…An increase in herbicide tolerance has been observed in many North American weeds over only a few decades (Davies, 1993). Evolution of zinc-tolerant populations of Deschampsia caespitosa and Anthoxanthum odoratum under electricity pylons has occurred in only 17 years (Al-Hiyali et al, 1990). In Germany, zinc-tolerant populations of A. capillaris evolved from nontolerant ones in a mere 3 years (Ernst et al, 1983).…”