scholarly journals Appreciation of tolerance at the impact of thermal stress on photosystem ii activity in the leaves of pedunculate oak (Quercus robur L.) trees of different ecological origin

2021 ◽  
Vol 13 (1(22)) ◽  
pp. 13-20
Author(s):  
Petru Cuza ◽  

Extreme weather events with high temperatures and strong sunlight have increased alarmingly in the last few decades, considerable affecting plant photosynthesis. In this study, the impact of thermal stress on photosystem II activity in the leaves of pedunculate oak trees (Quercus robur L.) of different ecological origin was assessed. Four days after the thermal shock application with a temperature of 50°C during 20, 40, 60 minutes, the processes of recovery on photosystem II activity in the leaves of the oak trees in the investigated provenances took place with different speed and fullness. The recovery of the functional state of photosystem II in the leaves of the trees showed that in the environmental conditions of the ,,Plaiul Fagului” reservation territory an advanced thermotolerance to the thermal stress action was specifi c for the origin from the north of the country (Edinet). The leaves of the trees of local and southern origin showed a low resistance to the thermal stress action. The advanced adaptation capacity, the high growth rate of the trees from the northern provenance suggest that the acorn harvested from the oaks of northern origin can be used for the works of extension of the afforestation areas in the central area of the Republic of Moldova.

Author(s):  
С.Н. Кружилин ◽  
Т.Ю. Баранова ◽  
А.А. Багдасарян

Государственный природный заказник "Горненский", расположенный в центральной части Ростовской области, являясь особо охраняемой природной территорией областного значения, имеет уникальные объекты, представленные искусственно созданными лесными насаждениями дуба черешчатого (Quercus robur L.). В современном лесном хозяйстве черноземной зоны дуб черешчатый продолжает занимать лидирующие позиции по хозяйственному значению. Большое внимание при выращивании леса уделяется продуктивности. Насаждения, устойчивые насаждение к болезням, вредителям и неблагоприятным природным явлениям, всегда являются продуктивными и имеют большой показатель запаса древесины на единицу площади. Усыхание дубрав в последние годы становится актуальной проблемой. Основными факторами этих процессов являются повреждения вредителями и инфекционными заболеваниями. Повышению устойчивости деревьев дуба черешчатого в насаждениях способствуют своевременные рубки ухода. Авторы провели анализ посадок дуба черешчатого, сформированных с участием основной сопутствующей породы – клена остролистного. Исследовано 2 варианта лесных культур дуба в условиях сухой дубравы (Д1), определены лесоводственно-таксационные показатели в разные возрастные периоды. Отмечается, что при отсутствии в них плановых рубок ухода в периоды с 25 до 40 и с 35 до 50 лет происходит падение бонитета с 1 до 2 класса. Наряду с этим отмечается суховершинность деревьев, что приводит к задернению поверхности почвы и, соответственно изменению условий произрастания. The Gornensky State NatureReserve,situated in the central part of the Rostov Region, isa protected natural area of regional significance. The reserve contains unique objects, represented by artificially created forest stands of pedunculate oak (Quercus robur L.). In the modern forestry of the Chernozem zone,pedunculate oak continues to take a leading position in terms of its economic value. Much attention is paid to productivity when growing forests. Plantings that are resistant to diseases, pests, and adverse natural phenomena are always productive and have a large stock of wood per unit area. The diebackof oak forests has become an urgent problem in recent years. The main factors of these processes are damage by pests and infectious diseases. Timely improvement felling of oak trees helps to increase the stability of the stands. The authors analyzed plantings of petiolate oak formed with the participation of the main accompanying species– Norwaymaple. Twovariants of forest oak plantationsin the conditions of a dry oak forest (D1) were studied, and forestry and taxation indicators were determined for different age periods. It is noted that in the absence of planned improvement felling in the periods from 25 to 40 and from 35 to 50 years, there is a drop in the yield class from 1 to 2. Along with this, the diebackof trees is noted, which results inthe grassing-downof the soil surface and, accordingly, changes in the growing conditions.


2005 ◽  
pp. 9-29 ◽  
Author(s):  
Dragan Karadzic ◽  
Tanja Milijasevic

The most frequent fungus species known as powdery mildews, causing the diseases of forest trees, were studied. Among forest woody species, oaks are especially susceptible to powdery mildew attack, and among them pedunculate oak (Quercus robur L) is highly endangered. This paper reports 49 species of powdery mildews. However, Microsphaera alphitoides has the greatest significance in forest economy, causing the decline of seedlings in nurseries and also aggravating the natural regeneration of pedunculate oak. This fungus, together with gypsy moth and honey fungus (Armillaria mellea) participates in the dying of old oak trees. Powdery mildews can be successfully controlled by fungicides, and sulphur fungicides Karatan and Rubigan are especially effective.


2020 ◽  
Vol 287 (1935) ◽  
pp. 20201303
Author(s):  
Laura J. A. van Dijk ◽  
Johan Ehrlén ◽  
Ayco J. M. Tack

Insects and pathogens frequently exploit the same host plant and can potentially impact each other's performance. However, studies on plant–pathogen–insect interactions have mainly focused on a fixed temporal setting or on a single interaction partner. In this study, we assessed the impact of time of attacker arrival on the outcome and symmetry of interactions between aphids ( Tuberculatus annulatus ), powdery mildew ( Erysiphe alphitoides ), and caterpillars ( Phalera bucephala ) feeding on pedunculate oak, Quercus robur , and explored how single versus multiple attackers affect oak performance. We used a multifactorial greenhouse experiment in which oak seedlings were infected with either zero, one, two, or three attackers, with the order of attacker arrival differing among treatments. The performances of all involved organisms were monitored throughout the experiment. Overall, attackers had a weak and inconsistent impact on plant performance. Interactions between attackers, when present, were asymmetric. For example, aphids performed worse, but powdery mildew performed better, when co-occurring. Order of arrival strongly affected the outcome of interactions, and early attackers modified the strength and direction of interactions between later-arriving attackers. Our study shows that interactions between plant attackers can be asymmetric, time-dependent, and species specific. This is likely to shape the ecology and evolution of plant–pathogen–insect interactions.


Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1425
Author(s):  
Bernd Degen ◽  
Yulai Yanbaev ◽  
Malte Mader ◽  
Ruslan Ianbaev ◽  
Svetlana Bakhtina ◽  
...  

As for most other temperate broadleaved tree species, large-scale genetic inventories of pedunculate oak (Quercus robur L.) have focused on the plastidial genome, which showed the impact of post-glacial recolonization and manmade seed transfer. However, how have pollen mediated gene flow and introgression impacted the large-scale genetic structure? To answer these questions, we did a genetic inventory on 1970 pedunculate oak trees from 197 locations in 13 European countries. All samples were screened with a targeted sequencing approach on a set of 381 polymorphic loci (356 nuclear SNPs, 3 nuclear InDels, 17 chloroplast SNPs, and 5 mitochondrial SNPs). In a former analysis with additional 1763 putative Quercus petraea trees screened for the same gene markers we obtained estimates on the species admixture of all pedunculate oak trees. We identified 13 plastidial haplotypes, which showed a strong spatial pattern with a highly significant autocorrelation up to a range of 1250 km. Significant spatial genetic structure up to 1250 km was also observed at the nuclear loci. However, the differentiation at the nuclear gene markers was much lower compared to the organelle gene markers. The matrix of genetic distances among locations was partially correlated between nuclear and organelle genomes. Bayesian clustering analysis revealed the best fit to the data for a sub-division into two gene pools. One gene pool is dominating the west and the other is the most abundant in the east. The western gene pool was significantly influenced by introgression from Quercus petraea in the past. In Germany, we identified a contact zone of pedunculate oaks with different introgression intensity, likely resulting from different historical levels of introgression in glacial refugia or during postglacial recolonization. The main directions of postglacial recolonization were south to north and south to northwest in West and Central Europe, and for the eastern haplotypes also east to west in Central Europe. By contrast, the pollen mediated gene flow and introgression from Q. petraea modified the large-scale structure at the nuclear gene markers with significant west–east direction.


2019 ◽  
Vol 68 (1) ◽  
pp. 111-115 ◽  
Author(s):  
Bernd Degen ◽  
Ruslan Yanbaev ◽  
Yulai Yanbaev

Abstract We studied the genetic composition of 200 pedunculate oak (Quercus robur) trees at nine nuclear microsatellite gene loci. We sampled nine locations in an area of 1100 km by 400 km in the South-Ural. The question was to analyse the genetic differentiation of the oaks at the south-east edge of the species distribution area. We observed relatively high values of genetic differentiation and fixation (delta=0.387, FST=0.0652, FST(Hedrick)=0.407) compared to values from the centre of the species distribution range. Bayesian clustering analysis revealed three genetic groups. Presence of all genetic groups was detected at all locations, but oak trees in the extreme east of the Ural Mountains were genetically most different. We hypothesise that genetic drift influenced the observed pattern.


2021 ◽  
Vol 64 (1) ◽  
pp. 5-12
Author(s):  
Heinrich Spiecker

Large dimension branch free wood of pedunculate oak (Quercus robur L.) and sessile oak (Q. petraea (Matt.) Liebl.) is highly valued, while small sized and low-quality oak timber generate little income. This paper describes how large dimensions of branch free wood can be produced by applying appropriate silvicultural measures. The results are based on measurements of oak trees in various regions in Germany and Denmark. Two management phases are distinguished: In phase 1 pruning is emphasized and at the beginning of phase 2 future crop trees are selected to promote diameter growth of these oak trees. The resulting guidelines provide a quantitative basis for objective-oriented oak management.


2017 ◽  
Vol 28 (1) ◽  
pp. 14-19 ◽  
Author(s):  
Jolanta Bąk-Badowska ◽  
Ilona Żeber-Dzikowska ◽  
Jarosław Chmielewski

Abstract The aim of the study was to demonstrate the degree of healthiness of the pedunculate oak (Quercus robur) acorns found in the Włoszczowa-Jędrzejów Nature Park (abbreviation: W-JOChK) and in the neighbouring area. It was dealt with by making the analysis of health of the acorns (total 3,600). The research material included the samples of fallen down acorns, collected under the pedunculate oaks in Kurzelów (W-JOChK), as well as Żelisławice. The study was conducted from late September 2014 to early October 2015. The analysis of acorns demonstrated that over 50% of the acorns were damaged by insects. The ‘perpetrators’ of the damage proved to be Curculio glandium (Coleoptera: Curculionidae - acorn weevil) and Cydia splendana (Lepidoptera: Tortricidae - chestnut tortrix). It was stated that acorns from the pedunculate oak trees, which were found on the protected area, were twice less frequently inhabited by Curculio glandium than those originating from the trees in Żelisławice - near the industrial firm. The damages caused by Cydia splendana in both study sites were similar in number. The results indicate that the acorns of oaks in more polluted environment are probably more vulnerable to infestation by insects.


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