Combined chlorophyll fluorescence techniques to study environmental impact on the mountain moss Polytrichum commune

Two chlorophyll fluorescence (ChlF) methods were used to study the effects of high light (photoinhibition) and dehydration, common stressors of the alpine environment, on primary photosynthetic processes in the moss Polytrichum commune from the Czech Republic, the Jeseníky Mountains. Photoinhibition (PI) was studied in fully hydrated thalli of P. commune and during the period of spontaneous desiccation. Time courses of Kautsky kinetics (KK) of ChlF and derived parameters: maximum quantum yield (FV/FM), effective quantum yeld (ΦPSII), and non-photochemical quenching parameters, were measured before and after the samples were treated with high light (1500 µmol m-2 s-1 PAR) for 60 min. Dehydration effects were tested in two sets of experiments with a Pulse-Amplitude-Modulation fluorometry (PAM) and Fast Chlorophyll Fluorescence induction curve (OJIP) techniques. In PAM tests, the desiccating samples were exposed to saturating light pulses every 10 min. in order to obtain ΦPSII and non-photochemical quenching (NPQ). In the second dehydration experiment, OJIP transients of ChlF were repeatedly recorded, OJIP-derived ChlF parameters were plotted against relative water content (RWC) monitored during desiccation. Combined ChF techniques provided insights into the mechanisms activated during P. commune desiccation, such as dissipation of excess absorbed energy through heat dissipation, and conformational changes or destructions of the light harvesting complexes. Combination of stressors resulted in amplified interference with the photosynthetic machinery, even when the added stressor (dehydration) was applied in low dose.

In Vitro Observations of the Interactions between Pholiota carbonaria and Polytrichum commune and Its Potential Environmental Relevance

Wildfires play a critical role in maintaining biodiversity and shaping ecosystem structure in fire-prone regions, and successional patterns involving numerous plant and fungal species in post-fire events have been elucidated. Evidence is growing to support the idea that some post-fire fungi can form endophytic/endolichenic relationships with plants and lichens. However, no direct observations of fire-associated fungal–moss interactions have been visualized to date. Therefore, physical interactions between a post-fire fungus, Pholiota carbonaria, and a moss, Polytrichum commune, were visually examined under laboratory conditions. Fungal appressoria were visualized on germinating spores and living protonemata within two weeks of inoculation in most growth chambers. Appressoria were pigmented, reddish gold to braun, and with a penetration peg. Pigmented, reddish gold to braun fungal hyphae were associated with living tissue, and numerous mature rhizoids contained fungal hyphae at six months. Inter-rhizoidal hyphae were pigmented and reddish gold to braun, but no structures were visualized on mature gametophyte leaf or stem tissues. Based on our visual evidence and previous work, we provide additional support for P. carbonaria having multiple strategies in how it obtains nutrients from the environment, and provide the first visual documentation of these structures in vitro.

The Mitochondrial Genome of Nematodontous Moss Polytrichum commune and Analysis of Intergenic Repeats Distribution Among Bryophyta

An early-branched moss Polytrichum commune is a widely accepted model object for ecological, environmental, physiological, and genetic studies. Its mitochondrial genome has been sequenced and annotated. The genome contains 67 genes in total and has a length equal to 114,831 bp, which exceeds the length of most known mitochondrial genomes for mosses. A phylogenetic tree based on 33 coding sequences of mitochondrial genome was constructed, and the pairwise identity of whole mitogenome sequences was estimated for 44 Bryophyta species. Based on the analysis of pairwise identity, it was shown that mitogenomes of Tetraphis pellucida and Buxbaumia aphylla sufficiently differ from those of other Bryophyta species. The first known Bryophyta mitogenome rearrangement was identified in Pogonatum inflexum within Polytrichopsida. Based on the intergenic repeats occurrence in 44 bryophyte mitochondrial genomes and available data on repetitive elements content in other Viridiplantae groups, it was noted for the first time that greater stability of the moss’s mitogenomes is probably associated mainly with the absence of long (>1 kb) repeats. The phenomenon of absence of the intergenic repetitive elements in the terminal clades species was discovered.

The status of Listera cordata cenopopulation in the nurgush state nature reserve

The census of Listera was conducted on routes with a total length of 11.05 km on 2020. The width of the recording transect was 10 m. In suitable habitats, plants were located in relatively dense groups, separated from each other by considerable distances. We have revealed 31 subpopulations of Listera with a total of 283 generative shoots and 1949 vegetative ones. The density of Listera in the surveyed habitats was 3.50 ind./ha, density in the subpopulations was from 5 to 13 ind./sq.m, on the average 6.81 ind./sq.m. All the Subpopulations were confined to areas of moss cover dominated by sphagnum mosses, but with the obligatory presence of Polytrichum commune and hypnum mosses. The setting and ripening of Listera fruits in 2020 were high: fruits were developed from 84% of flowers. The Tulashor site of the Nurgush State Nature Reserve plays an important role for the conservation of Listera cordata in the Kirov region.

The pigment complex and photosynthetic activity in the annual cycle of Polytrichum commune in the forest belt of the Khibiny Mountains on the Kola Peninsula of Russia

This paper presents data on the content and ratio of pigments, photosynthesis rate, and assimilation number throughout the annual cycle of Polytrichum commune in the forest belt of the Khibiny Mountains. It is shown that the activity of the pigment complex in the photosynthetic organs of P. commune is preserved and maintained over 2 years. The highest content of plastid pigments in this year’s shoots was recorded in fall, in the past year’s shoots in the summer. In winter, the content of chlorophylls in the photosynthetic organs of this year’s shoots decreased in 1.5 times relative to the summer maximum, and carotenoids - in 1.4 times. In the past year’s shoots, no significant changes in the content of the pigments were noted. During the active vegetation period, the photosynthetic intensity in this year’s shoots is in 1.5 times as high as that in the past year’s shoots. At the end of the growing season in the past year’s shoots the value of LHC (76%) due to their immersion deep into the moss clumps and shading them with this year’s shoots. Chlorophyll’s efficiency (assimilation number) in P. commune shoots of different ages in early spring (April) is in 2 times as high as that in fall (October).