Seasonal Changes in the Photosynthetic Activity of Terrestrial Lichens and Mosses in the Lichen Scots Pine Forest Habitat

Abstract

Photosynthetic activity is one of the most important metabolic processes that can be quickly and easily studied in the field. It can be used for identifying the environmental factors affecting ecosystem balance, as any stressor influencing metabolic and physiological processes will have a measurable effect on photosynthesis. The aim of this study was to measure the photosynthetic activity of selected lichens and mosses and investigate its changes resulted from diurnal and seasonal variability. We studied two lichens (Cladonia mitis Sandst and Cladonia uncialis (L.) Weber ex F.H. Wigg.) and two mosses (Pleurozium schreberi (Willd. ex Brid.) Mitt. and Dicranum scoparium (L.) Hedw.). Samples were collected in the area of lichen Scots pine forest of the “Bory Tucholskie” National Park. Our study revealed that the photosynthetic activity of cryptogams depended on species, season, time of the day, and water availability. Cladonia species, which are the main component of lichen Scots pine forests, have higher photosynthetic activity than Pleurozium schreberi, which represents species of fresh coniferous forests. Photosynthetic activity increased from spring through summer and reached the highest values in autumn. It was also higher in soaked samples collected in the morning and afternoon compared to noon. Despite the water access, noon samples still showed the lowest activity. This can result from natural changes in humidity during the day to which cryptogams are well-adapted.

Effect of light stress on maximum photochemical efficiency of photosystem II and chloroplast structure in cryptogams Cladonia mitis and Pleurozium schreberi

“…Establishment and maintenance of laboratory cultures of lichen and bryophytes Species of lichen C. mitis and bryophyte P. schreberi were randomly collected in Bory Tucholskie National Park within the lichen Scots pine forest community (Cladonio-Pinetum Ass.) in February 2022 (Węgrzyn et al, 2020;2021a;2021b). The collected samples were cleaned of plant debris and soil particles and divided into 3 study samples, which were later placed in 3 experimental glass containers (aquariums) with different light treatments.…”

“…As part of our investigation, we not only measured the photosynthetic activity of the lichens in their nonsoaked state, but also irrigated them for a period of two hours, since the importance of hydrating the samples under investigation before measuring their physiological parameters has already been shown in the previous study (Węgrzyn et al 2021b). Exposure to the sunlight of the dry lichen thallus can cause the accumulation of severe damage in PS II, and water is the endogenous factor for the regeneration of the damaged apparatus (Veres et al 2022a).…”

Effect of light stress on maximum photochemical efficiency of photosystem II and chloroplast structure in cryptogams Cladonia mitis and Pleurozium schreberi

“…Handy PEA + fluorometer (Handy PEA, Hansatech Instrument Ltd, King's Lynn, Norfolk, England). The fluorometer light probe emitted the dose of excitation light, which allowed recording the maximum photochemical efficiency of photosystem II (Fv/Fm) (Chowaniec and Rola, 2020;Dziurowicz et al, 2022;Węgrzyn et al, 2021).…”

“…This approach was adopted based on importance of hydrating the samples under investigation before measuring their physiological parameters, that has already been shown in the previous study (Węgrzyn et al, 2021). Exposure to the sunlight of the dry lichen thallus can cause the accumulation of severe damage in PS II, and water is the endogenous factor for the regeneration of the damaged apparatus (Veres et al, 2022a).…”

Is Active Moss Biomonitoring Comparable to Air Filter Standard Sampling?

“…During the experiment, the exposed mosses significantly decreased their photosystem II activity. The rate of accumulation of elements depends on environmental conditions [51]; in the same way, the result of a photosynthetic activity measurement is dependent on the conditions under which it is performed [52]. Sudden changes in environmental conditions and (associated with it) stress cause the moss condition to deteriorate [53,54].…”