Fluorescence procedures to assess the photosynthetic resilience in Scots pines after a surface fire

Forest fire represents one of the most serious abiotic stress factors that influence the function and productivity of ecosystems globally. Siberian pine forests are often exposed to forest fires but they are not always harmful to them. We have analyzed the effects of repeated heat stress on the photosynthetic apparatus of Scotch pines before and after surface fire exposure that occurred in the growing season in 2014. The survey area was the forest steppe zone of Krasnoyarsk region (South Siberia). First, we investigated the changes in the temperature-dependent responses of photosynthesis in the needles by means of fast and delayed chlorophyll fluorescence. Our results are indicative of some acclimation of Scotch pines after fire to the repeated high temperature stress. Also, this paper discusses the possibility of using chlorophyll fluorescence parameters for evaluating the presence of physiological changes after the fire affects. The time after fire effect and growth season were found to be important to assess the repair of photosynthesis and pigment content

Influence of high-temperature convective flow on viability of Scots pine needles (Pinus sylvestris L.)

During a forest fire, plants are affected by high temperatures causing stress. At the time of burning, it is difficult to record temperature changes in tree crowns and the associated effects on photosynthesis. This paper presents the results of modelling a high-temperature effect simulating a convective flow from a ground fire. Evaluation of the response was carried out by the parameters of rapid fluorescence (Fv/Fm, ETR), the state of the pigment complex, and the relative water content in the needles. To characterize the degree of heat endurance and short-term effects concerning thermal damage, saplings of Scots pine (Pinus sylvestris L.) were used at different times during the growing season (June, July, August, September). Experimental heating at 55 C lasted for 5 and 10 min. There were different levels of heat resistance by the needles. Data in June show that heating of the saplings significantly suppressed photosynthesis. In July, August, and September, the photochemical quantum yield (Fv/Fm) was restored to 75% and 60% from the initial level after 5- and 10-min heating, respectively. The electron transport rate (ETR) for saplings in September was restored to their initial level within 3 days after a short heat exposure. Restoration of the photosynthetic activity in needles was observed after a 5-min impact, but by the end of the study period, restoration had not reached control values. A longer heating of 10 min resulted in an irreversible suppression of photosynthesis and destruction of the photosynthetic apparatus, as evidenced by the decrease in the number of photosynthetic pigments

Photosynthetic Pigments in Siberian Pine and Fir under ClimateWarming and Shift of the Timberline

Research Highlights: For the first time, the Pinus sibirica Du Tour and Abies sibirica L. conifer forest at theWest Sayan ridge timberline has been explored to reveal which species is likely to react to climate change and a shift of the timberline. Such a shift may modify the ecological functions of the forests. Background and Objectives: Long-term climate change has become obvious in the mountains of southern Siberia. Specifically, a half-century rise in annual mean temperatures has been observed, while precipitation remains unchanged. Trees growing at the timberline are likely to strongly react to climate alterations. The objective was to estimate which of the two species sharing the same habitat would benefit from climate alteration and shifting of the timberline. Materials and Methods: At several altitudes (from 1413 to 1724 m a.s.l.), samples of P. sibirica and A. sibirica needles have been collected and contents of chlorophyll a and b as well as carotenoids were measured in June 2019. The temperature of needles of the two species was measured in both cloudy and sunny weather conditions. Results: The studied species have been shown to have di erent patterns of pigment variations with the growth of altitude. The decline of chlorophylls and carotenoids was more pronounced in P. sibirica (ratio at timberline ca. 2.2) than in A. sibirica (ratio ca. 3.1). Accordingly, the electron transport rate decreased more strongly in P. sibirica at the timberline (ca. 37.2 mol of electrons/m2 s1) than in A. sibirica (56.9 mol of electrons/m2 s1). The temperatures of needles in both cloudy and sunny weather were higher in A. sibirica (10.5 and 43.3 C, respectively) than in P. sibirica (3.8 and 24.2 C, respectively). Conclusions: The considered physiological and ecological traits show that P. sibirica is better protected from higher-altitude hazards (excess insolation, rise of temperature etc.) than A. sibirica. P. sibirica may be therefore a more likely winner than A. sibirica in the movement of the mountain timberline under climate warming in the area

Influence of oil on the grain culture of S.cereale (L)

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала

Influence of oil on the grain culture of S.cereale (L)

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала

Quantitative characteristics of the phases of winter dormancy of conifer species at a site in Central Siberia

Traditionally the registration of seasonal changes in plant growth and development has been carried out phenologically, i.e., qualitatively using visual inspection. However, since the process of plant acclimatization to winter dormancy involves reversible biochemical and physiological changes at the level of cells, quantitative methods can be applied to determine the duration and the depth of winter dormancy in perennial plants. We used a method based on detecting thermally induced changes in the zero-level fluorescence (TICZF) on needles from four Siberian coniferous trees. Needles of Picea obovata Ledeb. and Abies sibirica Ledeb. recover from the state of winter dormancy much faster than those of Pinus sibirica Du Tour and Pinus sylvestris L. The photosynthetic apparatus in the needles of A. sibirica may be damaged during the spring period, characterized by unstable weather, when after several days of warm weather, the plants prematurely recover from winter dormancy. We conclude that under conditions of climate warming tree, species like A. sibirica may suffer from severe diebacks due to desiccation caused by premature break of winter dormancy

Quantitative characteristics of the phases of winter dormancy of conifer species at a site in Central Siberia

Traditionally the registration of seasonal changes in plant growth and development has been carried out phenologically, i.e., qualitatively using visual inspection. However, since the process of plant acclimatization to winter dormancy involves reversible biochemical and physiological changes at the level of cells, quantitative methods can be applied to determine the duration and the depth of winter dormancy in perennial plants. We used a method based on detecting thermally induced changes in the zero-level fluorescence (TICZF) on needles from four Siberian coniferous trees. Needles of Picea obovata Ledeb. and Abies sibirica Ledeb. recover from the state of winter dormancy much faster than those of Pinus sibirica Du Tour and Pinus sylvestris L. The photosynthetic apparatus in the needles of A. sibirica may be damaged during the spring period, characterized by unstable weather, when after several days of warm weather, the plants prematurely recover from winter dormancy. We conclude that under conditions of climate warming tree, species like A. sibirica may suffer from severe diebacks due to desiccation caused by premature break of winter dormancy

How much carbon can the Siberian boreal taiga store: a case study of partitioning among the above-ground and soil pools

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.In the context of global carbon cycle management, accurate knowledge of carbon content in forests is a relevant issue in contemporary forest ecology. We measured the above-ground and soil carbon pools in the dark-coniferous boreal taiga. We compared measured carbon pools to those calculated from the forest inventory records containing volume stock and species composition data. The inventory data heavily underestimated the pools in the study area (Stolby State Nature Reserve, central Krasnoyarsk Territory, Russian Federation). The carbon pool estimated from the forest inventory data varied from 25 (t ha−1) (low-density stands) to 73 (t ha−1) (highly stocked stands). Our estimates ranged from 59 (t ha−1) (low-density stands) to 147 (t ha−1) (highly stocked stands). Our values included living trees, standing deadwood, living cover, brushwood and litter. We found that the proportion of biomass carbon (living trees): soil carbon varied from 99:1 to 8:2 for fully stocked and low-density forest stands, respectively. This contradicts the common understanding that the biomass in the boreal forests represents only 16–20 % of the total carbon pool, with the balance being the soil carbon pool. © 2015, Northeast Forestry University and Springer-Verlag Berlin Heidelberg

How much carbon can the Siberian boreal taiga store: a case study of partitioning among the above-ground and soil pools

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала.In the context of global carbon cycle management, accurate knowledge of carbon content in forests is a relevant issue in contemporary forest ecology. We measured the above-ground and soil carbon pools in the dark-coniferous boreal taiga. We compared measured carbon pools to those calculated from the forest inventory records containing volume stock and species composition data. The inventory data heavily underestimated the pools in the study area (Stolby State Nature Reserve, central Krasnoyarsk Territory, Russian Federation). The carbon pool estimated from the forest inventory data varied from 25 (t ha−1) (low-density stands) to 73 (t ha−1) (highly stocked stands). Our estimates ranged from 59 (t ha−1) (low-density stands) to 147 (t ha−1) (highly stocked stands). Our values included living trees, standing deadwood, living cover, brushwood and litter. We found that the proportion of biomass carbon (living trees): soil carbon varied from 99:1 to 8:2 for fully stocked and low-density forest stands, respectively. This contradicts the common understanding that the biomass in the boreal forests represents only 16–20 % of the total carbon pool, with the balance being the soil carbon pool. © 2015, Northeast Forestry University and Springer-Verlag Berlin Heidelberg