Abies sibiricaledeb. meiosis during microsporogenesis in disturbed forest ecosystems

Abstract

Meiosis during microsporogenesis in Siberian Fir (Abies sibirica Ledeb.) in the East Sayan middle mountains (the territory of national park "Stolby", the valley of the river Laletin and Upper Kaltat river) has been studied. Microsporogenesis has been investigated in details in healthy, damaged by fungi (Melampsorella cerastii Wint.) and drying trees. Features of A. sibirica meiosis have been revealed. Meiotic abnormalities have been found in all trees at different stages. Specific abnormalities have also been revealed in some trees.

Fossilized pollen malformations as indicators of past environmental stress and meiotic disruption: insights from modern conifers

“…2), we summarize possible developmental origins of pollen malformation types observed in this study that are applicable to the fossil record by drawing upon historical observations in the cytological literature of extant conifers and seed plants. In studies to date, the developmental origins of certain malformation traits have not explicitly been discussed, given that cytological studies on conifer microsporogenesis mentioning them focus on genotypic rather than phenotypic implications of meiotic deviations (Andersson 1947; Runquist 1968; Bazhina et al 2007a,b, 2011; Noskova et al 2009), while morphological studies addressing malformations do not evaluate their developmental origins (Lakhanpal and Nair 1956; Srivastava 1961; Mehra and Dogra 1965). However, there are inferences that can be made about malformation origins based on what is known about microsporogenesis in saccate conifers and the nature of some morphological deviations.…”

“…Such conditions could account for the substantially wider range of meiotic irregularities previously reported in Abies sibirica Ledeb. specimens grown in arboretum settings than in natural ecosystems (Bazhina et al 2007a). Modern thresholds for environmental stress based on cultivated trees (and to some extent, natural ecosystems) could therefore be higher than in the deep past.…”

“…Although certain morphological deviations in both fossil and modern pollen walls can be inferred to result directly from certain types of developmental disruptions, traceable to specific stages in meiosis I and II (Chira 1967; Bazhina et al 2007a,b, 2011; Noskova et al 2009) (Fig. 2), it can be difficult to infer presence of a specific environmental stress using higher frequencies of developmental deviations alone, as they arise from numerous genotype by environment interactions (Veilleux and Lauer 1981).…”

“…Furthermore, environmental stresses are not mutually exclusive with respect to one another, meaning more than one stress can synchronously exacerbate selective pressures on plant communities, generating pollen malformations in the process. For example, Bazhina et al (2007a) noted numerous saccate pollen malformations in drought-stressed modern conifers in Siberia that were exposed to industrial air pollution and were also being attacked secondarily by pathogens.…”

“…Malformed pollen grains have been observed in modern conifers under numerous environmental stresses such as sharp decreases in temperature (Christiansen 1960; Chira 1967), warming and drying climate (Bazhina et al 2007a; Noskova et al 2009), photochemical and industrial pollution (Renzoni et al 1990; Mičieta and Murín 1996; Presnukhina and Kalashnik 2003), geochemical pollution (Tretyakova and Noskova 2004), pathogenic fungal attack/disease (Bazhina et al 2007a), heightened ultraviolet-B radiation (UV-B; 280 to 315 nm) (Benca et al 2018), and nuclear radiation (Sirenko 2001). Aside from nuclear radiation, these stresses are not limited to anthropogenic activities, and therefore could have been experienced by gymnosperms before the Industrial Revolution.…”