Der Einfluß von kontinuierlichen,niedrigen SO2-Begasungen auf den Phenolgehalt und die Phenoloxidase-Aktivität in Blättern einiger Waldbaumarten

Influence of continuous fumigation by low levels of SO₂ on the phenolic contents and phenoloxidase activities in leaves of forest trees. Potted clonal trees of Norway spruce, black alder and English birch were continuously exposed to low levels of So₂ in fumigation chambers. The phenolic content of the Norway spruce needles was increased consiberably over the controls months before the trees showed any symptoms of damage to the naked eye. Fumigated black alder had a significant higher phenoloxidase activity in the leaves; but this increase only occurred two weeks before the development of necroses. In English birch neither the phenolic content nor the phenoloxidase activity was changed against the unfumigated controls during the course of the experiment.     

Modellversuche zum Einfluß der Nährstofïversorgung auf die SO2-Empfindlichkeit von Pflanzen1

Studies on the influence of nutrition on the susceptibility of plants to SO₂ . The mineral nutrition of plants is of great importance for their susceptibility to air pollutants. Substrate media with ammonia as nitrogen source, deficiency of potassium and low pH-values reduce the buffer capacity and the cation contents. Buffer capacity and cation contents play important roles for the detoxification of SO₂-borne products. Low cation contents and a reduced buffer capacity produce a severe increase of the SO₂-effects. Decreased sulfur nutrition results in a considerable delay of the beginning of the SO₂-injuries.     

Einfluß von SO2 und HF auf freie Aminosäuren der Fichte (Picea abies [L.] Karsten)

The influence of SO₂ and HF on free amino acids of spruce . The influence of the air pollutants SO₂ and HF on composition and amount of free amino acids was investigated. Distinct differences in the pattern of amino acids are caused, particularly in glutaminic acid and compounds based on it.     

Die Wirkung wäßriger Streuextrakte verschiedener Waldbäume auf Mycelwachstum und Konidiosporenkeimung von Fomes annosus (Fr.) Cke.

The effect of water extracts of leaf and needle litter from different forest trees on the mycelial growth and the germination rate of conidia of Fomes annosus (Fr.) Cke. Litter extracts from various forest trees and stands have distinct effects on mycelial growth and germination rate of conidia of Fomes annosus. The effects depend on concentration of the extract, period of extraction and on date of collecting the litter samples.     

Der Einfluß von Asphaltmischanlagen auf die Vegetation unter besonderer Berücksichtigung der Erdölbitumendämpfe1

The influence of hot mix asphalt plants on vegetation with special regard to vapours from asphaltic bitumen . Vapours from asphaltic bitumen can be neglected as a factor injurious to plants because of the small amount generally exhaled by hot mix asphalt plants. Vegetation damage observed was due to sulfur dioxide, dust and soot. A method for identifying condensed vapours from asphaltic bitumen deposited on plant surfaces is discussed.     

Untersuchungen über den Einfluß von Cuticularwachsen auf die Infektionsfähigkeit pathogener Pilze

The effect of cuticular waxes on the infection rate of pathogenic fungi. 2. Rhytisma acerinum, Microsphaera alphitoides and Fusarium oxysporum . Cuticular waxes of Acer and Quercus species stimulate germination rate and germ-tube development of certain foliar pathogens. The stimulation increases with host susceptibility. In the case of Rhytisma acerinum, the chemical composition of the leaf wax may be responsible for the host specificity of physiological races. Cuticular waxes showed a marked effect on Fusarium oxysporum also. In some cases, individual chemical components of different fractions seem to play a role in the mechanism of resistance.     

Untersuchungen über den Einfluß von Cuticularwachsen auf die Infektionsfähigkeit pathogener Pilze

The effect of cuticular waxes on the infection rate of pathogenic fungi. 1. Lophodermium pinastri and Botrytis cinerea . Spore germination and growth rate of germ-hyphae of Lophodermium pinastri and Botrytis cinerea are influenced by low concentrations of cuticular waxes, added to the germination medium. The stimulating effect increases with decreasing resistance of the species or race used for wax sampling. Generally the separately tested alcohol-, aldehyde-, ester-, fatty acid- and hydrocarbon fractions induce similiar but less pronounced reactions than total waxes. Exceptions occur. They led to suggestions in direction to single chemical components causing resistance. – Finally alcohol and hydrocarbon chromatOgrams of cuticular waxes for Pinus montana, P. nigra and Picea abies are presented for the first time.     

Der Einfluß gasförmiger Luftschadstoffe auf die EpicuticularWachse von Quercus robur

Influence of gaseous pollutants on the epicuticular wax of Quercus robur . The effects of SO₂, NO, and ozone on the epicuticular wax of Q. robur were studied by scanning electron microscopy and by measuring the contact angle of water droplets on the leaf surfaces. The treatments did not induce any significant differences in the wax micromorphology.     

Der Nachweis unsichtbarer („physiologischer”) Fluor-Immissionsschädigungen an Waldbäumen durch eine einfache kolorimetrische Bestimmung der Peroxidase-Aktivität

The detection of hidden F-injury of forest trees by a simple colorimetric determination of peroxidase actívity . The paper describes a simple routine method for determining colorimetrically peroxidase activity (p. a.) in foliage of forest tree species, including conifers. The effect of factors such as foliage age, F Content, external F dust, necrosis etc. on p. a. is investigated. Analyses of plants exposed at different distances to F exhalates of an aluminum plant show that with decreasing distance F content and p. a. increase. P. a. thus is an indicator of air pollution effects on tree physiology even in the range where no visible symptoms of injury occur.     

Untersuchungen iiber die Resistenzeigenschaften einiger Weißpappelklone gegenüber der Triebspitzenkrankheit

The resistance of several white poplar-clones against Pollaccia radiosa. Continuing the work of Weisgerber (1967,1968 and 1969) clone-typical forms of resistance against spring defoliation (shoot-dieback), caused by Pollaccia radiosa were investigated in several Leuce-poplarclones. The most obvious differences in attack occur under natural conditions. The observed differences concerning the type of resistance (infection versus spreading in the host) seem to depend on the anatomical structure of the host.     

Der Einfluß einer praxisnahen SO2-Begasung auf das 14CO2-Fixierungsmuster von Buchen (Fagus sylvatica L.)

The influence of a SO₂-fumigation on the ¹⁴CO₂-fixation pattern of beeches (Fagus sylvatica L.) under field conditions. The influence of a fumigation with a low SO₂ concentration on the metabolism of beech leaves (Fagus sylvatica L.) was investigated. Changes due to SO₂ were observed in the sulfur content, the ¹⁴CO₂-uptake and the ¹⁴CO₂-fixation pattern. The use of these parameters for the indication of air pollution effects on plants is discussed.     

Der Einfluß von Fluorverbindungen auf die Chloroplasten-pigmente von Pappel-, Holunder- und Fliederblättern im Freiland bei verschiedener Belastung1

The effect of different concentrations of fluorine on the chloroplast pigments of Poplar, Elder and Lilac occurring in the field. An important aim when studying the effects of pollutants is to find methods indicating very early injury. The concentrations of the chlorophylls a and b and of the carotinoids in leaves of Populus canadensis Moe., Sambucus nigra L., and Syringa vulgaris were measured. When affected by fluoride-ions the leaves of P. canadensis show significant loss of the three pigments. The two other species seem to be more resistant.     

Physiologische Reaktionen der Fichte (Picea abies) auf komplexen SO2- und Trockenstreß

Physiological reactions of spruce (Picea abies) on complex SO₂- and drought-induced stress. Part 3. Responses of SO₂-stressed spruces to subsequent drought-induced stress. SO₂-stressed spruces under drought-stress showed less reduced water content, less increased osmotical potential and less restricted photosynthesis compared to spruces without preceding SO₂-stress and thus seemed to be in a better physiological situation. Their ability to retain water (in cut-off twigs) as well as their ability to withstand a quick and strong water-loss in the needle-tissue without cell-damage were reduced. Reasons for the temporarily favourable effect of a pre-going SO₂-stress in surviving a drought-stress are discussed.     

Vergleich der Attraktivität von 3 Pheromonfallentypen auf die Mehlmotte,Ephestia kühniella Zeller

In the laboratory three types of pheromone traps for the Mediterranean Flour Moth,Ephestia kühniella were tested. The trap of the Albany International Corp. was compared with the Detia Mottenindikator and a trap of the Institute for Pesticide Research in Wageningen. In separated series of trials with paired traps, all six possible combinations between traps and lures were tested. The direct comparison between Detia Mottenindikator and the Albany trap revealed no significant difference in moth catch. But the shape of the Detia trap is better than the Albany one, whereas for the lures the reverse holds true. The best combination is therefore Detia trap/Albany lure. Significant fewer moths were caught with the trap of the Institute for Pesticide Research than with the Albany trap.     

Simultane Messung der Chlorophyll Fluoreszenz-Kinetik bei verschiedenen Wellenlángen als rasches Verfahren zur Frühdiagnose von Immissionsbelastungen an Waldbäumen: Ozoneinwirkungen auf Buchen und Pappeln

Simultaneous measurement of chlorophyll fluorescence-kinetics at two different wavelengths as a rapid and an early detection method of air pollution damage on trees: Ozone effects on beech and poplar . A newly defined light adaption index A_P shows the stress influence already before the comparable and known vitality index R_fd and the appearance of visible ozone symptoms on foliage.