Genetic diversity is often considered a major determinant of long term population persistence and its potential to adapt to variable environmental conditions. The ability of populations to maintain their genetic diversity across generations seems to be a major prerequisite for their sustainability, which is particularly important for keystone forest tree species. However, little is known about genetic consequences of demographic alterations occurring during natural processes of ecological succession involving changes in the species composition. Using microsatellites, we investigated genetic diversity of adult and offspring generations in beech (Fagus sylvatica L.) and oak (Quercus robur L.) populations coexisting in a naturally established old-growth forest stand, showing some symptoms of ongoing ecological succession from oak- to beech- dominated forest. In general, adult generations of both species exhibited high levels of genetic diversity (0.657 for beech; 0.821 for oak), which, however, depended on the sets of selected genetic markers. Nevertheless, several symptoms such as differences in genetic diversity indices between generations, significant levels of inbreeding (up to 0.029) and low estimates of effective population size (48–80) confirmed the declining status of the oak population. On the other hand, the uniform distribution of genetic diversity indices across generations, low levels of inbreeding (0.004), low genetic differentiation among adults and offspring and, most importantly, large estimates of effective population size (119–716), all supported beech as a successive and successful tree species in the studied forest stand.
Quercus robur seedlings are very often infested by oak powdery mildew caused by Erysiphe alphitoides. This disease attacks primary leaves with high insolation. In our experiment seedling growth in different light conditions was observed. Seedlings were derived from intact seeds or from seeds where the distal ends of acorns were cut off. Acorns were sown in pots at four light conditions (2%, 8% and 30% light transmittance and in full sunlight). For half of the seedlings we reduced the influence of powdery mildew by using a fungicide. Height of seedlings, shoot dry mass and the degree of damage caused by Erysiphe alphitoides were measured. The highest damages were in full light conditions and the lowest in the 30% light treatment. The influence of acorn reduction on powdery mildew infection was not significant (p=0.0763), however, in the full light conditions the seedlings from cut acorns were ca. 30% less damaged. The cutting of acorns also alters the height of seedlings and shoot mass. The tallest seedlings were from cut seeds growing in the 30% light treatment. The influence of the fungicide was lowest in the 30% light treatment where the decrease in damage was only ca. 10%. For nursery practice we can say that oak seedling production from cut off acorns under 30% light transmittance should give the best results of seedling growth even without the fungicide application.
The impact of artificial mycorrhization with 6 vegetative inocula (produced by research procedures at the Forest Pathology Department at Agricultural University in Cracow) of ectomycorrhizal fungi: Hebeloma claviceps, H. leucosarx, H. longicaudum, H. sacchariolens, H. sinapizans and H. trunkatum on following parameters: the level of mycorrhization of Scots pine and pedunculate oak seedlings, the profile of frequency and types of ectomycorrhizae on these seedlings, the influence of intervention on the growth and development characteristics of shoot and root system was studied. The results of the mycorrhization described above were compared with the mycorrhization with Polish commercial vegetative inoculum of Hebeloma crustuliniforme carried out on the seedlings of the same tree species grown in containers. The assessment revealed that all fungi species representing Hebeloma genus were very good symbionts for pine. The index of mycorrhization of the root system in each case was high and achieved level between 0,86 for H. longicaudum to 1,0 for H. sacchariolens and H. claviceps. The growth and development of oak seedlings in container culture were improved in the highest degree by H. crustuliniforme, H. leucosarx, H. sinapizans and H. sacchariolens.
Solute accumulation in plant leaves during drought through accumulation of organic compounds is known to compensate turgor loss andpromote higher stomatal conductance at lower water potentials. Recent studies have involved experiments on saplings and younger stands, while evidence of osmotic adjustment in adult pedunculate oak under natural stand conditions on different sites is scarce. Pressure volume curves technique was used to define differences in osmotic potential – water stress adaptation – of 120 year oldped unculate oak trees in two managedforest complexes andin virgin forest remnant. Tree response between the managedstandafter thinning andthe standwithout any silvicultural measures within same forest complex was also compared during summer months in two consecutive (dry and favourable) years with groundwater table. Significant differences were observed in adaptation between forest complexes and during dry (2003) and favourable (2004) years. Osmotic component of thinnedforest was the highest, showing most negative values of stress adjustment. Measured values on all plots responded well to drop in groundwater table, especially in pronounced drought conditions. Such response may be in relation with lower stand density and increased individual space for growth in thinned stand. Adult oaks did not loose their ability to water stress adaptation, in spite of their age and progressively decreasing health conditions.
Effects of elevated temperature and soil pollution with fluorine on host-pathogen relations were studied in seedlings of the pedunculate oak (Quercus robur L.) inoculated with oak powdery mildew (Microsphaera alphitoides Griff. et Maubl.) and control seedlings. The plants were grown for 1month in elevated temperature (on average by 1.6°C) and soil pollution with sodium fluoride (330 ppm F). The above factors did not have any significant effect on nitrogen content of leaves or on concentrations of metabolites favourable to growth and development of the fungal pathogen (total non-structural carbohydrates, including soluble carbohydrates and starch) and those unfavourable to fungi (soluble phenols, condensed tannins and lignins). The elevated temperature and fluorine pollution did not affect the leaf infection rate. However, a significant temperature × pollution interaction was observed in inoculated seedlings. At the elevated temperature, fluorine caused a less severe infection by powdery mildew. This could be due to a direct toxic effect of fluorine on the pathogen or by an indirect influence, resulting from changes in levels of other metabolites, which were not analysed in this study. The inoculation of oak seedlings with powdery mildew caused a decline in the carbohydrate content of leaves but did not have any significant effect on levels of other analysed metabolites. However, it significantly affected the distribution of phenols and lignins in oak leaves. Those compounds accumulated within necrotic lesions and in adjacent cells. Our results do not enable drawing definite conclusions on effects of a slight rise in temperature and a relatively low level of fluorine pollution of the soil on relations between the pedunculate oak and oak powdery mildew. Lower values of the leaf infection rate in seedlings growing in elevated temperature and fluorine pollution suggest that in warmer years a lower level of infection by M. alphitoides may be expected in areas affected by fluorine pollution.
Future climatic warming may modifyinsect development, sex ratio, quantitative changes in populations that could affect the frequency of outbreaks. Here we analyzed the influence of temperature on larval growth and development in the gypsy moth (Lymantria dispar L.). The larvae were reared at three constant temperatures: 15, 20 or 25°C, and fed with leaves of the English oak (Quercus robur L.). Larval mortality, duration of development (DD), relative growth rate (RGR), total mass of food eaten (TFE), and pupal mass (PM) were estimated. Larval mortality was lowest at 20°C, higher at 25°C, and highest at 15°C. DD significantly decreased with increasing temperature and depended on sex. The influence of temperature on the shortening of DD was stronger in males than in females. RGR significantly depended on temperature and was the highest at 25°C, and lowest at 15°C. At 15°C, RGR did not change markedly with time. In contrast, RGR at 20°C was characterized bya continuous decreasing trend. At 25°C, RGR was very high for 2 weeks but quickly declined afterwards. Temperature did not affect the TFE. PM was significantly correlated with temperature and sex. PM of females was higher at 20°C than at 15 and 25°C, in contrast to that of males, which was similar at 20 and 25°C, and higher than at 15°C. For larval growth and development, the most favourable was the medium temperature (20°C). The least favourable temperature for females was 25°C, for males 15°C. The results suggest that global warming may modifythe future sex ratio of gypsy moths that may affect insect development and outbreaks.
Aleje przydrożne są ważnym, kulturowym elementem krajobrazu Polski. Utworzone z długowiecznych gatunków drzew często pozostają świadkami dawnych wydarzeń i zachwycają monumentalnym wyglądem. W artykule przedstawiono rys historyczny i inwentaryzację alei dębowej w miejscowości Ulucz, w gminie Dydnia.
W pracy przedstawiono wyniki analizy wpływu nacisku jednostkowego wywar-tego na glebę na wzrost i jakość sadzonek sosny zwyczajnej Pinus sylvestris L., buka pospolitego Fagus sylvatica L. oraz dębu szypułkowego Quercus robur L., wyrosłych w warunkach powierzchni doświadczalnych założonych pod okapem drzewostanu. Określoną wartość nacisku jednostkowego uzyskano przy użyciu prototypu ciągnikowego urządzenia do wywierania kontrolowanego nacisku na glebę. Badania wykonano w kulisach szkółki leśnej „Kłaj” w Nadleśnictwie Niepołomice na dwóch powierzchniach doświadczalnych. Przygotowano łącznie sześć serii poletek, stosując nacisk jednostkowy o różnych wartościach (50, 100, 150, 200 oraz 250 kPa) oraz poletka kontrolne (bez nacisku), na które wysiano nasiona analizowanych gatunków. Po 7 miesiącach wyrosłe sadzonki wykopano i przewieziono do laboratorium, gdzie pomierzono średnicę w szyi korzeniowej, długość części nadziemnej i podziemnej oraz suchą masę poszczególnych części roślin. Uzyskane dane poddano analizie statystycznej przy użyciu programu Statistica. Wyniki wskazują, że wartość zastosowanego nacisku jednostkowego wywieranego na glebę wpływała na parametry sadzonek analizowanych gatunków. Dla dębu szypułkowego i sosny zwyczajnej większość parametrów sadzonek zmniejszała się ze wzrostem nacisku, dla buka pospolitego analizowane parametry zwiększały się, co sugeruje możliwość lepszego odnawiania się tego gatunku na bardziej zbitym podłożu. Sadzonki wyrosłe na poletkach kontrolnych z reguły cechowały się największymi wartościami średnimi cech, z wyjątkiem buka.
Uzyskanie kwalifikowanego materiału siewnego wymaga wykonania szeregu czynności fizycznych, mających źródło w znajomości praw rządzących procesami rozdzielczymi. Podstawą ich są różnice w niektórych właściwościach fizyko-mechanicznych pomiędzy poszczególnymi składnikami mieszanin ziarnistych. Znajomości takiej wymaga ponadto konstruowanie podzespołów maszyn i urządzeń do uszlachetniania materiału siewnego oraz efektywna eksploatacja czyszczalni i sortowników mechanicznych oraz innych maszyn do obróbki nasion. Zarówno współczesne jak i dawne konstrukcje separatorów są oparte na doświadczeniu praktyków, a nie teoretycznych koncepcjach mających źródło w gruntownej znajomości agrofizyki nasion. Ze względu na powyższe niezbędna jest szczegółowa analiza cech rozdzielczych dębu, uwzględniająca także cechy nie wykorzystywane w leśnictwie do tej pory, a które powinny być wzięte pod uwagę w konstrukcji przyszłościowych rozdzielaczy uniwersalnych. Mechaniczna separacja nasion wymaga znajomości ich podstawowych parametrów geometrycznych, w tym wielkości i kształtu. Pomiary wspomnianych parametrów wykonano korzystając z komputerowej analizy obrazów nasion, uzyskanych z aparatu cyfrowego. Celem pracy była analiza wielkości i kształtu żołędzi dębu szypułkowego (Quercus robur L.) opisana współczynnikami kształtu, z uwzględnieniem przynależności do klas żywotności. Przyjęto klasyfikację nasion na 3 frakcje pomiarowe, biorąc za podstawę rozwój zarodka oraz szacowaną na tej podstawie spodziewaną zdolność kiełkowania nasion. Wyniki badań wykazały, że cechy geometryczne żołędzi nie mogą być uznane za cechy rozdzielcze, zatem nie ma możliwości przeprowadzenia procesu separacji w oparciu o wielkość nasion. Podczas badań zaobserwowano także, że tradycyjny sposób suszenia żołędzi, celem przygotowania do przechowywania, nie umożliwia uzyskania jednorodnej wilgotności końcowej. Jedynie nasiona żywotne o dużych zarodkach wykazują właściwą wilgotność, znacząco wyższą od pozostałych. Stanowi to zapewne jedną z przyczyn spadku zdolności kiełkowania nasion w trakcie przechowywania.