@article{Jamnická2020,
title = {Physiological vitality of Norway spruce (\textit{Picea abies} L.) stands along an altitudinal gradient in Tatra National Park},
author = {Gabriela Jamnická and Alena Konôpková and Peter Fleischer and Daniel Kurjak and Peter Petrík and Anja Petek and Hana Húdoková and Peter Fleischer and Zuzana Homolová and Marek Ježík and Ľubica Ditmarová},
doi = {10.2478/forj-2020-0019},
isbn = {2454-034X},
year = {2020},
date = {2020-12-02},
journal = {Central European Forestry Journal},
volume = {66},
number = {4},
pages = {227-242},
abstract = {Nowadays, a large area of Norway spruce forest stands in Europe is disturbed by windstorm and, subsequently, bark beetle outbreaks. We investigated the state of three disturbed spruce stands along an altitudinal gradient in Tatra National Park (Slovakia) through various physiological processes. Tree-growth characteristics, the mineral nutrition in the needles, and photosynthetic efficiency were assessed. Two techniques of chlorophyll a fluorescence and analyses of assimilatory pigments were used to detect the changes in photosynthesis functioning. Also, the heat sensitivity of photosystem II was tested. Our results showed that these stands are located in nutrient-poor environments. We recorded similar contents of nitrogen, phosphorus, potassium, sodium, zinc, and iron in all stands. Down the vertical transect, the contents of calcium, magnesium, and manganese significantly decreased and the non-essential aluminium increased. Based on stem circumference measurements, water deficit occurred during the vegetation season in all stands, but with the smallest magnitude highest U–stand. We found some photosynthetic constraints: slightly lower chlorophyll contents in all stands were recorded; however, seasonal dynamics with increasing chlorophyll concentration in the highest U–stand were observed. Moreover, the photochemistry of the lowest D–stand was the most negatively influenced by simulated heat, as the photosynthetic performance index, and the density of the active reactions centres significantly decreased and the values of the K–step and basal fluorescence increased. Therefore, we can conclude the different levels of physiological vitality in these naturally damaged spruce stands, with the best physiological performance of the trees in the highest stand.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Kubov2020,
title = {Drought or Severe Drought? Hemiparasitic Yellow Mistletoe (\textit{Loranthus europaeus}) Amplifies Drought Stress in Sessile Oak Trees (\textit{Quercus petraea}) by Altering Water Status and Physiological Responses},
author = {Martin Kubov and Peter Fleischer Jr. and Jozef Rozkošný and Daniel Kurjak and Alena Konôpková and Juraj Galko and Hana Húdoková and Michal Lalík and Slavomír Rell and Ján Pittner and Peter Fleischer},
doi = {10.3390/w12112985},
issn = {2073-4441},
year = {2020},
date = {2020-10-24},
journal = {Water},
volume = {12},
number = {11},
abstract = {European oak species have long been considered relatively resistant to different disturbances, including drought. However, several recent studies have reported their decline initiated by complex changes. Therefore, we compared mature sessile oak trees (Quercus petraea (Matt.), Liebl.) infested versus non-infested by hemiparasitic yellow mistletoe (Loranthus europaeus Jacq.) during the relatively dry vegetation season of 2019. We used broad arrays of ecophysiological (maximal assimilation rate Asat, chlorophyll a fluorescence, stomatal conductance gS, leaf morphological traits, mineral nutrition), growth (tree diameter, height, stem increment), and water status indicators (leaf water potential Ψ, leaf transpiration T, water-use efficiency WUE) to identify processes underlying vast oak decline. The presence of mistletoe significantly reduced the Ψ by 1 MPa, and the WUE by 14%. The T and gS of infested oaks were lower by 34% and 38%, respectively, compared to the non-infested oaks, whereas the Asat dropped to 55%. Less pronounced but significant changes were also observed at the level of photosystem II (PSII) photochemistry. Moreover, we identified the differences in C content, which probably reduced stem increment and leaf size of the infested trees. Generally, we can conclude that mistletoe could be a serious threat that jeopardizes the water status and growth of oak stands.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Konôpková2020b,
title = {Origin rather than mild drought stress influenced chlorophyll a fluorescence in contrasting silver fir (\textit{Abies alba Mill.}) provenances},
author = {Alena Konôpková and Hana Húdoková and Marek Ježík and Daniel Kurjak and Gabriela Jamnická and Ľubica Ditmarová and Dušan Gömöry and R. Longauer and Roberto Tognetti and Eva Pšidová},
doi = {10.32615/ps.2020.011},
issn = {0300-3604},
year = {2020},
date = {2020-01-01},
journal = {Photosynthetica : international journal for photosynthesis research},
volume = {58},
pages = {549-559},
abstract = {The performance of PSII photochemistry in five Central European provenances of silver fir differing in the altitude of origin (250-1,300 m a.s.l.) were studied using the chlorophyll a fluorescence parameters derived from the JIP-test. Measurements were performed on two dates in 2016: at the start and at the peak of growing season. Within this period, mild water stress was recorded, allowing us to monitor changes in photochemistry under drought conditions. Our results confirmed that silver fir is generally resistant to water deficit at the PSII level. However, the differences in photochemistry between provenances originating from different climatic conditions were observed. The high-altitude provenances (from wetter and colder localities) achieved higher PSII efficiency, which was also supported by clear trends along the climatic and geographic gradients of the provenance origins. After the drought, comparable PSII efficiency for low-altitude provenances and even higher for these originating in higher altitudes was observed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{Konôpková2020d,
title = {Impact of the European bark beetle \textit{Ips typographus} on biochemical and growth properties of wood and needles in Siberian spruce \textit{Picea obovata}},
author = {Alena Konôpková and Konstantin E Vedernikov and Egor A Zagrebin and Nadezhda A Islamova and Roman A Grigoriev and Hana Húdoková and Anja Petek and Jaroslav Kmeť and Peter Petrík and Anna S Pashkova and Anastasia N Zhuravleva and Irina L Bukharina},
doi = {10.2478/forj-2020-0025},
issn = {2454-034X},
year = {2020},
date = {2020-01-01},
journal = {Central European Forestry Journal},
volume = {66},
number = {4},
pages = {243-254},
abstract = {European spruce bark beetle Ips typographus is an important driver of ecological processes in spruce stands, with severe effects on forestry economies. To prevent bark beetle outbreaks, early detection of infestations is a crucial step in forest management. It is expected that bark beetle infestation modifies biochemical composition of wood and needles, alters physiological responses in the early stage of infestation, which results in the reduction of tree growth and ultimately a tree death. Therefore, we studied the differences in biochemical composition of wood, content of photosynthesis-related pigments, shoot morphology, and growth between the healthy Siberian spruce trees (Picea obovata) and trees which were infested by I. typographus. The study was performed in five experimental plots established in the south of the Udmurt Republic in the European part of the Russian Federation. Three infested and three non-infested trees were chosen on each plot. Our results showed no significant effect of bark beetle infestation on the content of main structural components of wood-holocellulose (cellulose and hemicellulose) and lignin. On the other hand, we found differences in the content of extractive substances in the wood. Specifically, we found a higher tannin content in the non-infested trees. The content of photosynthesis-related pigments differed between the non-infested and infested trees as well. Unexpectedly, bark beetle infestation caused the overproduction of both pigment types rather than their degradation. Moreover, we observed that a higher amount of total extractive substances positively affected the incremental growth, whereas tannins supported the growth of shoots and needles.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}