Section: Monitoring of natural and anthropogenically disturbed areas
Due to climate change, the boundaries of the ranges of many plants are shifting both in latitudinal and altitudinal directions. In particular, the forest boundary shifts upward in the mountains. A transect with four sampling plots was laid on the slope of the Ergaki Ridge (Western Sayan), crossing the treeline (upper border) of the forest as it transits from the mountain taiga to the rocky-tundra belt. It has been revealed that Siberian pine (Pinus sibirica Du Tour) plants use various survival strategies when spreading above the treeline, which manifests itself in a change in the shape of the crown form from stem-like to krummholz, as well as seasonal changes in the pigment complex and parameters of chlorophyll fluorescence in needles. In all habitats of P. sibirica, an important parameter for predicting an increase in the needle weight, which, in turn, ensures the productivity of the entire plant, is the maximum rate of non-cyclic electron transfer in the summer. In spring and autumn (in the course of transition from winter dormancy to vegetation and back), the ratio of chlorophylls and carotenoids from forest to mountain-tundra communities decreases in the pigment complex of needles. Siberian pine specimens growing above the treeline and having mechanisms for dissipating excess light energy by light-induced non-photochemical fluorescence quenching have a clear advantage in gaining needle weight over other plants from the same sample plots. For trees from sample plots located in forest environment, a high proportion of nonphotochemical fluorescence quenching is rather a disadvantage. The considered parameters of chlorophyll fluorescence can be used to identify P. sibirica individuals resistant to habitat conditions above the treeline and their subsequent use in breeding to increase the area of woodlands under climate change.
ISSN 1995-4301
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