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).