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Abstract <p>The evergreen shrub <i>Vaccinium vitis-idaea</i> L. is one of the most common species in the natural flora of Yakutia permafrost ecosystems. We investigated how low temperatures affect parameters of the OJIP chlorophyll <i>a</i> fluorescence transient curves to follow the seasonal acclimation of PSII in current-year leaves. The relative amounts of Q<sub>B</sub>-non-reducing centers, Q<sub>A</sub>-non-reducing centers and the rate of the RCs closure were found to increase when the temperature drops in autumn. The decrease in ψ<sub>Eo</sub> and φ<sub>Eo</sub> was observed, which indicates the limitation of photosynthetic electron transport activity. The fall in the average daily temperature from 0.1 to –8.1°C during October led to the increase in constitutive thermal dissipation of excess light energy, which was manifested in the increase in parameter DI<sub>0</sub>/RC. It is concluded, that the high DI<sub>0</sub>/RC values is due to the thermal dissipation in closed/inactive RCs and Z mediated constitutive quenching in antenna. However, a significant part of the PSII in overwintering leaves retained photochemical activity. The appearance of K-band in OJIP curves recorded during autumnal cold acclimation and after snowmelt suggests that PSII complexes may include the population of PSII devoid of active oxygen evolving complexes (OEC). Thus, our results deepen the understanding of the mechanisms of adaptation of the photosynthetic apparatus of evergreen plants wintering under snow.</p>

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Seasonal Acclimation of Photosystem II in Lingonberry (Vaccinium vitis-idaea L.) Leaves in the Natural Conditions of Central Yakutia

  • 期刊论文

  • 发表日期：

    2025年6月17日

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  • V. E. Sofronova,
  • F. F. Protopopov,
  • V. V. Nokhsorov,
  • O. V. Dymova,
  • T. K. Golovko

摘要

Abstract

The evergreen shrub Vaccinium vitis-idaea L. is one of the most common species in the natural flora of Yakutia permafrost ecosystems. We investigated how low temperatures affect parameters of the OJIP chlorophyll a fluorescence transient curves to follow the seasonal acclimation of PSII in current-year leaves. The relative amounts of QB-non-reducing centers, QA-non-reducing centers and the rate of the RCs closure were found to increase when the temperature drops in autumn. The decrease in ψEo and φEo was observed, which indicates the limitation of photosynthetic electron transport activity. The fall in the average daily temperature from 0.1 to –8.1°C during October led to the increase in constitutive thermal dissipation of excess light energy, which was manifested in the increase in parameter DI0/RC. It is concluded, that the high DI0/RC values is due to the thermal dissipation in closed/inactive RCs and Z mediated constitutive quenching in antenna. However, a significant part of the PSII in overwintering leaves retained photochemical activity. The appearance of K-band in OJIP curves recorded during autumnal cold acclimation and after snowmelt suggests that PSII complexes may include the population of PSII devoid of active oxygen evolving complexes (OEC). Thus, our results deepen the understanding of the mechanisms of adaptation of the photosynthetic apparatus of evergreen plants wintering under snow.