Photosynthetic pigments activity in plants leaves under the conditions of weather anomalies

St. Petersburg State University, Faculty of Biology, Department of Applied Ecology, Universitetskaya Emb. 7-9, St Petersburg, 199034, Russia

^* Corresponding author: elizaveta902@mail.ru

Abstract

The global climate change growing rate causes an increase in the frequency of weather anomalies, expressed in seasonally atypical temperature rises in various regions. Meteorological anomalies affect all components of living ecosystems, in particular – plant communities, and often have a negative impact, resulting in suppression of its components physiological functions, including photosynthetic activity of plants. In 2021, 2022 and 2024, summer weather anomalies were recorded in St. Petersburg at different pheno-phases of vegetation. In all three cases, the content of photosynthetic pigments (chlorophylls A and B, carotenoids) in leaves of higher plants was measured under conditions of exposure to the stress caused by seasonally atypical for the region weather conditions, as well as after the end of this factor impact in order to consider the plants capacity to restore photosynthetic pigments levels. It was shown that weather anomalies occurring in the earlier vegetation stages, when most plants of the studied region have not yet reached their maximum resistance to external stress, cause the most significant changes in their physiological state, which is slowly and not fully recovered after weather conditions normalization, while in the later pheno-phases chlorophylls levels were preserved to a greater extent.