Variability of photosynthetic pigments content in needles of pine with different form of seed scales apophysis under permanent excessive soil moisture

Variability and a comparative estimate of the photosynthetic pigments content in needles of one, two and three years old in two pine forms (Pinus sylvestris L.) under permanent excessive moisture of the northern taiga soils of the lower reaches of the Northern Dvina was studied. Forms of pine was distinguished by the type of development of the apophyses of the scales (f. gibba Christ - “convex”, f. plana Christ - “flat”, according to the method of L.F. Pravdin (1964). The levels of individual variability of the content of chlorophylls and carotenoids, their relative indices in different calendar periods are determined. A similarity in the character of the seasonal dynamics of the concentration of photosynthetic pigments of needles of different ages in pine with a “convex” and “flat” form of apophyses is established. Forms with different types of apophysis on peat bog soils do not differ significantly in the content of chlorophylls and carotenoids, relative values in the pigment complex of needles. This indicates the general nature of pigment formation and the similarity of adaptive reactions to environmental factors under the permanent soil moisture excess. In the spring, more intensive accumulation of chlorophylls was observed in two- and three-year-old needles compared with the one year-old needles for pine with a “flat” form of the apophyses. Concentration of carotenoids in the one-year needles was less in comparison with the needles of older ages for pine with the “convex” form of the apophysis. The pigment formation was associated with phenological phases of development in trees of different forms. Differences of pine trees with a convex shape of apophyses at the beginning of growth were more evident in the content of chlorophyll a in the one-year-old needles and the total content of photosynthetic pigments (CV = 19-20 %) than in the pine with the “flat” form of the apophysis (CV = 12 %). Pine with a “convex” type of apophysis had a more definite adaptive response to stress factors under of permanent excessive soil moisture in comparison with the pine with a “flat” type of apophysis. There is a tendency to decrease the proportion of chlorophylls in the light-harvesting complex in a long light day (in May) compared to the shortest day (in December) in both forms of pine. This is due to the adaptation of the photosynthetic apparatus of trees to light conditions in high latitudes.