Adaptation strategies and referencing trial of Scots and black pine populations subjected to heavy metal pollution

Abstract

The impact of industrial heavy metal pollution on Scots pine (Pinus sylvestris L.) and black pine (Pinus nigra Arn.) populations was investigated. Sampled pine stands, which were located in Upper Silesia (southern Poland) in an area strongly polluted by heavy metals, consisted of resistant and sensitive trees. To evaluate the adaptation process, genetic structure and diversity was tested using isozyme analysis. Higher levels of Zn, Pb, Cd and Cu were detected in needles of sensitive trees compared with resistant ones. With respect to morphology, Scots pines were more distinctly impaired than black pines. Although black pines had lower heavy metal concentrations, levels in 1-year-old needles, other than Cu, significantly exceeded “reference plant” values (Markert 1994). In both species, resistant trees demonstrated a lower degree of genetic variation than metal-sensitive trees with respect to some enzyme loci (SHDH A, PGI, PGM, MDH C and DIA). This observation was corroborated in sensitive trees by the smaller number of identified alleles and alleles per locus, absence of private alleles and significant excess of homozygotes in relation to expected Hardy–Weinberg equilibrium values. Assuming that only resistant trees of both species survive under conditions of prolonged soil contamination, the observed genetic structure implies that remaining populations will be depleted of some alleles of unknown adaptive value to future selection pressures. Genetic changes induced by heavy metals suggest an important role for specific enzymes—FEST, SHDH A and B, GOT B and PGI—in the adaptation process. Our results may serve as a basis for selection and propagation of individuals appropriate for re-cultivation of areas chemically degraded by industrial activity.

Tolerance to heavy metal stress in seedlings of three pine species from contrasting environmental conditions in Chile

“…have been reported to exhibit a lower degree of genetic variation than metal-sensitive trees with respect to some isozyme loci (SHDH A, PGI, PGM, MDH C and DIA). This allele depletion suggests that genetic changes induced by heavy metals may dramatically affect the adaptation process in forest tree populations (Chudzinska et al 2014).…”

Heavy Metal Contamination of Soils

“…The Ewens-Watterson test for neutrality and the test of Vitalis et al (2001) confirmed that allele frequencies at locus GOT B, as well as GDH, MDH C, NDH and SHDH B, of P. nigra have been influenced by selection, acting either directly on this locus or on adjacent genomic regions. Among the analysed microsatellite loci of nuclear DNA, two (PtTX 4001 and SPAC 11.4) appeared to be under balancing selection (Chudzińska 2013). SSR markers showed lower or higher genetic diversity of sensitive and resistant subpopulations with respect to certain loci.…”

“…Their number is higher under extreme conditions, e.g. in a pinе growing in a bog (Chudzińska 2013). The number of nuclеoli counted in silverstained interphase pine-seedling cells varied from 1 to 15 in data from Miasteczko Ś ląskie.…”

“…Studies on phosphoglucomutase (PGI) showed its relevance to oxygen availability, soil type and pH, and according to Van Assche et al (1998), it is likely to be under the control of selection as an enzyme involved in the process of glycolysis. Research conducted on the Scots pine with regard to the above-described allozyme data revealed clear differences between genotypes of trees resistant and susceptible to heavy metals (Chudzińska 2013;Chudzińska et al 2013a, b).…”

Peer Review #2 of "The effects of afforestation on soil bacterial communities in temperate grassland are modulated by soil chemical properties (v0.1)"

“…), an endemic tree in Inner Mongolia including in Honghua'erji, is one of the main forestation species in temperate regions of China. Scots pine (P. sylvestris L.), a relative of Mongolia pine that is widespread from Western Europe to Eastern Siberia, is also an important tree in forestry (Krakau et al 2013) and is physiologically sensitive to environmental pollution (Chudzińska et al 2014), geographic weather variation (Oleksyn et al 2003) and climate change (Hurme et al 1997;Savolainen et al 2004). Studies have demonstrated that Scots pine and, by reasonable extension, Mongolia pine have broad, plastic adaptability in response to environmental heterogeneity, supporting the wide use of these trees in afforestation.…”