Polycyclism and phenological variability in the common oak (Quercus robur L.)

Polycyclism is the ability for a plant to produce several flushes in the same growing season. The rare phenomenon of common oak (Quercus robur L.) summer flowering is proof of complex polycyclism. Common oak summer flowering and the unusual transformation of inflorescences were the starting point for this study of the phenological variability of common oak trees in identical site conditions. This paper presents comparative research of leaf flushing, flowering, and leaf fall phenophases in a common oak with summer flowering and a control tree in which this phenomenon was not observed. Both trees displayed frequent polycyclism (polyphase formation of annual shoots during the growing season), but with different intensities depending on the trees and the years. Compared to the control tree, the tree with summer flowering was characterized by a later onset of leaf-flush phenophase and leaf fall phenophase and a longer retention of the leaves in the crown.Projekat ministarstva br. 43007: Studying climate change and its influence on the environment: Impacts, adaptation and mitigatio

Effects of heavy thinning on Turkey oak (Quercus cerris L.) tree and stand increment

Na trajnim pokusnim plohama u umjetno podignutoj, srednjedobnoj, sastojini cera analizirani su efekti jake prorede na prirast stabala i sastojine, 5 i 10 godina od izvođenja. U 56. godini na pokusnoj plohi 1 (jaka proreda) prirašćivalo je 62% stabala, a na plohi 2 (sanitarna sječa) prirašćivalo je 95% stabala u odnosu na početno stanje u 46. godini. Pet godina poslije jake prorede na O.P.-1 tekući prirast temeljnice po hektaru iznosio je 89%, a zapremine 88%, u odnosu na (O.P.-2). U narednom petogodišnjem periodu tekući prirast temeljnice istih stabala na O.P.-1 iznosio je 95 %, a zapremine 92 %, u odnosu na O.P.-2. U cjelokupnom promatranom periodu tekući prirast temeljnice i zapremine preostalih stabala po hektaru na O.P.-1 iznosio je 92 %, odnosno 90 %, u odnosu na O.P.-2. Tekući prirast promjera, temeljnice i zapremine po stablu na O.P.-1. u prvom petogodišnjem periodu bio je veći za 21-22%, u drugom petogodišnjem periodu bio je veći za 26-30%, a u cjelokupnom promatranom periodu bio je veći za 23-25%, u odnosu na O.P.-2. Posle 10 godina na O.P.-1 srednji promjer preostalih stabala povećan je za 16,1%, temeljnica za 34,7%, a zapremina za 50,8%. Za isti period na O.P.-2 srednji promjer preostalih stabala povećan je za 13,2%, temeljnica za 28,4%, a zapremina za 40,4%. Zaključak je kako je jaka proreda povoljno utjecala na povećanje prirasta preostalih stabala. Ukupna produkcija na pokusnim plohama u 56. godini, pored isključivanja 38 % stabala iz proizvodnje na O.P.-1, približno je identična i održan je uspostavljeni rang (sa manjom razlikom) u veličini ukupne produkcije između oglednih ploha pre jake prorede.On permanent sample plots in middle-aged, artificially established, Turkey oak stand, the effects of heavy thinning (S.P.-1) and sanitation cutting (S.P.-2) were analysed on trees and stand increment, 5 and 10 years after cutting at the age of 46 years. Till the age of 56 years, 62% trees incremented on S.P.-1, and 95% trees on S.P.-2, compared to the initial state at the age of 46 years. Due to the devitalisation in the previous period, the remaining trees had the reduced capacity of growth reaction to the spatial increase and they compensated the increment loss slowly, which resulted due to the reduction of a great number of trees (38%) and volume (31%) on S.P.-1. Five years after heavy thinning on S.P.-1 the compensated volume was 57.4 % compared to the state before thinning, and after 10 years, the volume increased by 10% compared to the state before thinning. Compared to the volume per ha on S.P.-2 at the age of 56 years, the volume on S.P.-1 was lower by 20.6%. However, total production on sample plots at the age of 56 years, regardless of the elimination of 38% trees on S.P.-1, was approximately identical, and the established rank was maintained (with minor differences) in the size of the total production between the sample plots before the heavy thinning. Five years after heavy thinning on S.P.-1, current increment of basal area per ha was 89 %, and volume 88 %, compared to S.P.-2. In the following five-year period, current increment of basal area per ha of the same trees on S.P.-1 was 95%, and volume 92%, compared to S.P.-2. Throughout the study period, current increment of basal area and volume of the remaining trees per ha on S.P.-1 was 92% and 90%, compared to S.P.-2., as the consequence, primarily, of the different number of trees which incremented on sample plots. Current increment of diameter, basal area and volume per tree on S.P.-1. during the first five-year period was higher by 21-22%, during the second five-year period it was higher by 26-30%, and in the entire study period, it was higher by was 23-25%, compared to S.P.-2, and it is the consequence, primarily, of the different intensity of increment of the remaining trees on sample plots. In both five-year periods, the trees on S.P.-1 had greater diameter increment compared to the trees on S.P.-2 in all diameter degrees. After 10 years, on S.P.-1, mean diameter of the remaining trees increased by 16.1%, basal area by 34.7%, and volume by 50.8%. During the same period on S.P.-2 mean diameter of the remaining trees increased by 13.2%, basal area by 28.4%, and volume by 40.4%, so it can be concluded that heavy thinning had a favourable effect on the increase of increment of the remaining trees during the study period

Variability of the chloroplast dna of sessile oak (Quercus petraea agg. Ehrendorfer, 1967) in Serbia

Genetic variability of sessile oak (Quercus petraea agg. Ehrendorfer, 1967) in Serbia is estimated applying cpDNA universal primer pairs that were characterized by a high informative level for chloroplast genome variability assessment in previous investigations. Five different haplotypes were detected in the analyzed sample material from populations in Serbia

Some characters of the pollen of spring and summer flowering common oak (Quercus robur L.)

Summer flowering of the common oak is a natural rarity, considering the large area of the species natural distribution. This phenomenon can be classified as an ancestral (atavistic) property. Pollen morphological and physiological characters from spring flowering male inflorescences collected over the period 2004 - 2007 and summer flowering male inflorescences collected in 1999 were compared. The analysis included the pollen of a tree with frequent summer flowering and a control tree with spring flowering only. The size and form of summer pollen differed from the spring flowering pollen. The germination percentage and germination energy depended on the pollen growing medium (0, 5, 10, 15, 20, 25% sucrose solution), year of collection (2004 - 2007), temperature (+5°C and -20°C) and storage period (1 to 24 months). The study results are significant for the explanation of common oak phylogenetic development, and they contribute to the knowledge of pollen characters under the effects of different factors.Projekat ministarstva br. 17302

Age-Related Skeletal Muscle Atrophy in Humans: An Immunohistochemical and Morphometric Study

The aim of this study was to determine age-related changes in three human muscles with different function and location in the body. The cross sectional area and the percentage of fibers type I, type IIA and type IIX were studied in vastus lateralis, deltoideus and external intercostal muscle. Muscle samples were obtained from 30 male subjects, aged 20–80 years. Fiber types were defined immunohistochemically, using monoclonal antibodies specific for type I, type IIA and type IIX fibers. Cross sectional area of muscle fibers was analyzed morphometrically by computerized image analysis. All muscle fiber types (I, IIA, IIX) showed the reduction in the fiber size in all three examined muscles. In all muscles the proportion of type I and type IIA was changed, but not in type IIX. With increasing age results showed the increase in proportion of type I, while proportion of type IIA fibers decreased, with vastus lateralis muscle being the most affected. These results suggest that age-related muscle atrophy is not a general phenomenon, and does not affect all muscles equally

Polycyclism and phenological variability in the common oak (Quercus robur L.)

Polycyclism is the ability for a plant to produce several flushes in the same growing season. The rare phenomenon of common oak (Quercus robur L.) summer flowering is proof of complex polycyclism. Common oak summer flowering and the unusual transformation of inflorescences were the starting point for this study of the phenological variability of common oak trees in identical site conditions. This paper presents comparative research of leaf flushing, flowering, and leaf fall phenophases in a common oak with summer flowering and a control tree in which this phenomenon was not observed. Both trees displayed frequent polycyclism (polyphase formation of annual shoots during the growing season), but with different intensities depending on the trees and the years. Compared to the control tree, the tree with summer flowering was characterized by a later onset of leaf-flush phenophase and leaf fall phenophase and a longer retention of the leaves in the crown.Projekat ministarstva br. 43007: Studying climate change and its influence on the environment: Impacts, adaptation and mitigatio

Histological Correlation Between Pulp and Periapical Tissue Findings

Svrha je istraživanja bila analizirati korelaciju između histopatološkog nalaza pulpe i periapeksnoga tkiva za vrijeme otvorenog tipa infekcije pulpe na eksperimentalnome modelu psećih zuba. Devet pasa mješanaca podijeljeno je u četiri eksperimentalne skupine. Pulpa mandibularnih premolara (37 korjenova) je trepanirana s pomoću spororotirajućega zubnog koljičnika. Zubi su ostavljeni otvoreni djelovanju oralnoga mikro okruženja 20 dana (skupina I-dvije životinje, 8 korjenova), 35 dana (skupina II- tri životinje, 15 korijenova), 50 dana (skupina III- 2 životinje, 6 korijena) i 65 dana (skupina IV- dvije životinje, 8 korijenova) kako bi se inducirao pulpitis i apeksni parodontitis. Pulpe mezijalnoga korijena (9 korjenova) mandibularnih molara (kontrolni zubi) nisu bili izloženi oralnom mikrookruženju. Nakon završetka eksperimentalnog perioda životinje su žrtvovane. Nedemineralizirani zubi s okolnom alveolarnom kosti uklopljini su u metil-metakrilat i pripremljeni za histološko bojenje Toluidinskim modrilom. Nakon 20 dana izloženosti (skupina I) na 6 korjenova histopatološka dijagnoza bila je parcijalna nekroza pulpe, a na dva korijena nekroza je zahvatila cijelu pulpu. U skupini II (35 dana izloženosti) na tri korijena je dijagnoza pulpitis, na 6 potpuna nekroza pulpe, te na ostalih 6 djelomična nekroza pulpe. U skupini III (50 dana izloženosti) dva korijena imala su pulpitis, tri djelomičnu nekrozu pulpe, a jedan potpunu nekrozu pulpe. U skupinu IV (65 dana) sve su pulpe (8) bile potpuno zahvaćene nekrozom. Svi zubi s pulpitisom (5 korjenova), bez obzira na eksperimentalno razdoblje, imali su akutni serozni apeksni parodontitis, svi zubi s djelomičnom nekrozom pulpe (15 korjenova) imali su sliku subakutnog apeksnog parodontitisa. Zubi s potpunom nekrozom pulpe (19 korjenova) imali su sliku kroničnog apeksnog parodontitisa, a u jednom slučaju, u skupini III, periapeksni absces. Korelacija između histopatoloških nalaza pulpe i periapeksnog tkiva je statistički znatna (Pearsonova korelacija; r = 0,92, p < 0,01). Stanje pulpe u korelaciji je s histopatološkim nalazom periapeksnoga tkiva u otvorenom tipu infekcije pulpe. Akutni apeksni parodontitis s resorpcijom kosti počinje za vrijeme pulpitisa i može se razviti prije dvadesetoga dana izloženosti pulpe na modelu psećih zuba.The aim of the study was to analyse the correlation between histopathological findings of pulp and periapical tissue during open infection of the pulp on the experimental dog model. Nine mongrel dogs were divided into 4 experimental groups. Pulps of mandibular premolars (37 roots) were exposed using low-speed dental engine. Teeth were left open to the oral environment for 20 days (group I - two animals with eight roots), 35 days (group II - three animals with 15 roots), 50 days (group III - two animals with 6 roots) ahd 65 days (group IV - two animals with eight roots) to induce pulpitis and apical parodontitis. Pulp of the mesial root (nine roots) of a mandibular molar (control tooth) were not exposed to the oral environment. After the experimental period animals were sacrificed. Undemineralized teeth with bone, embedded in methylmetacrylate, were prepared for histological analysis (toluidine blue). After 20 days exposure (group I9 six roots had partial pulp necrosis and two roots complete pulp necrosis. In group II (35 days exposure) three pulps had pulpitis, six roots had complete pulp necrosis and six partial pulp necrosis. In group III (50 days exposure) two roots had pulpitis, three partial pulp necrosis and one complete pulp necrosis. In group IV (65 days) all pulps (eight) had complete pulp necrosis. All teeth had pulpitis (five roots), regardless of the experimental period, had acute serose apical periodontitis in periapical tissue, all teeth (15 roots) with partial necrosis had subacute apical periodontitis in the periapical tissue. Teeth with complete pulp necrosis (19 roots) had chronic apical periodontitis and in one case in group III abscessus periapicalis. Correlation between histopathological findings of the pulp and periapical tissue is statistically significant (Pearson correlation; r = 0.92, p < 0.01). The condition of the pulp correlated with the histopathological findings of periapical tissue in the open types of the pulp infection. Acute apical periodontitis with bone resorption began during pulpitits and can occur before 20 days of the pulp exposure in the dog