Comparing Norway spruce and silver fir regarding impact of bark wounds (original) (raw)
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Forests
Xylem traumatic resin ducts (TRDs) in Douglas-fir form in response to mechanical injury, fire, and root pathogens, but it is unknown if these form at the stem in response to bark-beetle-associated fungi. Meanwhile, TRDs are rarely documented in lodgepole pine. In the southern Rocky Mountains, TRD formation in the two species from sterile (Control) and fungal inoculation treatments (Aggressive, Weak (Douglas-fir only)) were compared; predicting the following: (1) both trees would produce TRDs in response to fungal treatments; (2) in Douglas-fir, Aggressive treatment would promote denser and larger TRDs than Weak or Control treatments; and (3) interspecifically, Douglas-fir would produce a higher density of TRDs than lodgepole pine in Aggressive treatments. Two months post-treatment, the position of TRDs indicated these were only induced on all Douglas-fir treatments. Aggressive and Weak treatments had similar responses, except a second TRD line formed in two Douglas-fir Aggressive tr...
Mechanical injury and fungal infection induce acquired resistance in Norway spruce
Tree Physiology, 1999
Norway spruce trees (Picea abies (L.) Karst.) pretreated by wounding and fungal infection showed highly enhanced resistance to a subsequent challenge inoculation with the pathogenic bluestain fungus Ceratocystis polonica (Siem.) C. Moreau. This is the first time the effectiveness of the constitutive and inducible defenses has been shown to depend on prior wounding and infection in conifers, although such acquired resistance has previously been found in several angiosperms. Trees that were pretreated with a combination of 12 bark wounds (1.6 × 10 cm), four fungal inoculations and four sterile inoculations 1--15 days before mass inoculation with C. polonica at 400 inoculations per square meter over a 0.8 m stem section had significantly shorter necroses in the phloem, less bluestained sapwood, and less dead cambium than untreated control trees. Pretreatment with four fungal or sterile inoculations alone did not lead to enhanced resistance. Pretreatment by bark wounding alone seemed to provide an intermediate degree of resistance compared to bark wounding, fungal inoculations and sterile inoculations combined. All trees had a marked increase in the number of resin ducts in the year of inoculation compared with previous years, suggesting that formation of traumatic resin ducts play an important role in the development and maintainance of enhanced resistance.
Forests, 2021
The aim of the research was to check whether the healing of bark-stripping wounds of the silver fir tree trunks reduces the share of wood-decomposing fungi, which may be the result of inter-species interactions. The study carried out in Gorce National Park in Polish Western Carpathians analyzed drill holes of sapwood from three types of wounds (fresh, healed and old) on fir trunks with a diameter at breast height (DBH) of 4.0–16.9 cm as a result of bark-stripping by red deer (Cervus elaphus). In the wood of fresh wounds Alternaria alternata (Fr.) Keissl. and Arthrinium arundinis (Corda) Dyko & B. Sutton had the largest share in mycobiota. Phompsis spp. and the species Sydowia polyspora (Bref. & Tavel) E. Müll. and Epicoccum nigrum Link were also isolated. The dominants in old wounds were Eutypa spp., Phomopsis spp. and Cylindrobasidium evolvens (Fr.) Jülich. Healed wounds were dominated by Trichoderma atroviride P. Karst, a fungus antagonistic to many fungal pathogens. Such properti...
Trees - Structure and Function, 2004
The anatomical defense responses in stems of Norway spruce (Picea abies) clones of different resistance to pathogenic fungi were characterized over time and distance from small mechanical wounds or wounds inoculated with the root rot fungus Heterobasidion annosum. Common responses for both treatments included division of ray parenchyma and other cells in the cambial zone, accumulation of phenolic inclusions in ray parenchyma cells, activation of phloem parenchyma (PP) cells, and formation of traumatic resin ducts (TDs) in the xylem. TD formation occurred synchronously from a tangential layer of cells, or symplasmic domain, within the zone of xylem mother cells. TD induction is triggered by a signal, which propagates a developmental wave in the axial direction at about 2.5 cm per day. TDs are formed at least 30 cm above single inoculations within 16-36 days after inoculation. The size and number of TDs is attenuated further away from the inoculation site, indicating a dose-dependent activity leading to TD development. Compared to sterile wounding, fungal inoculation gave rise to more and larger TDs in all clones, and multiple rows of TDs in weak clones. Fungal inoculation also induced the formation of more new PP cells, increasing the number of PP cells in the phloem in the year of inoculation up to 100%. TD and PP cell formation was greater in susceptible compared to resistant clones and after fungal versus sterile inoculation. Potential mechanisms responsible for this variable response are discussed
Wound Response of the Bark in Healthy and Declining Silver Firs (Abies Alba)
IAWA Journal, 1994
The bark of five healthy and six declining silver firs (Abies alba Mill.) was artficially wounded in July 1991. Structural changes were observed 6, 9, 16,23, and 40 days later. After 6-9 days, there was necrosis and deposition of polyphenols in the exposed tissues. Hypertrophy of the axial and ray parenchyma, and hyperplasia of the rays resulted in the formation of a parenchymatic zone below the necrotic tissues. The outermost cells of this zone just below the necrotic tissues exhibited thickening of walls and lignification in the corners of individual cells. Except in two apparently healthy trees and one strongly declining test tree, intracellular suberin was detectable in some lignified cells by day 16. By then polyphenols were visible in the axial parenchyma cells underneath the parenchymatic zone. Between 23 and 40 days after wounding, progressive suberisation resulted in the formation of a 'ligno-suberised zone', which fused with the phellem of the pre-existing periderm...
Anatomical-based defense responses of Scots pine (Pinus sylvestris) stems to two fungal pathogens
Tree Physiology, 2006
We investigated the cellular responses of stem tissues of mature Scots pine (Pinus sylvestris L.) trees to inoculations with two fungal pathogens. The bark beetle vectored fungus, Leptographium wingfieldii Morelet, induced longer lesions in the bark, stronger swelling of polyphenolic parenchyma cells, more polyphenol accumulation and increased ray parenchyma activity compared with the root rot fungus, Heterobasidion annosum (Fr.) Bref., or mechanical wounding. Axial resin ducts in the xylem are a general feature of the preformed defenses of Scots pine, but there was no clear induction of additional traumatic axial resin ducts in response to wounding or fungal infection. The anatomical responses of Scots pine to pathogen infection were localized to the infection site and were attenuated away from bark lesions. The responses observed in Scots pine were compared with published studies on Norway spruce (Picea abies (L.) Karst.) for which anatomically based defense responses have been well characterized.
Induced Resistance to Pathogenic Fungi in Norway Spruce
PLANT PHYSIOLOGY, 1999
Norway spruce (Picea abies) trees (approximately 16 m high) of a single clone were used to study the effects of fungal infection and wounding on induction of resistance to the bark beetle-associated bluestain fungus Ceratocystis polonica. A dose-response experiment was designed involving three different dosages of fungal (fungus and wound) and sterile agar (wound) pretreatment inoculations (10, 50, or 100 inoculations/m 2 on the stem between 0.8 and 2.0 m high). Three weeks after pretreatment, trees were challenged with a massive C. polonica inoculation (400 inoculations/m 2 ). Control trees that received no pretreatment were heavily colonized and killed by the challenge inoculation. The high and medium fungal pretreatments reduced subsequent fungal colonization success by 76% to 97% relative to the control, and fungal pretreatments protected the trees much more efficiently than sterile agar pretreatments. The protection was demonstrated to be local and not systemic in a subsequent experiment, where trees were pretreated with the medium fungal dosage on the lower bole and challenge inoculated further up the stem. Protection was also demonstrated to be pathogen nonspecific, as trees that had been pretreated with a medium dosage of the root rot fungus Heterobasidion annosum showed enhanced resistance to challenge inoculation with C. polonica.
Physiological and Molecular Plant Pathology, 2001
Xylem defence responses occurring in pot-grown Eucalyptus nitens (Maiden) saplings were analysed within the ®rst few weeks following stem wounding and inoculation with the non-aggressive decay fungus Ganoderma adspersum (Schulz). The fungus colonized the dead xylem cells up to 5 mm above and below the wound after 30 days. Evidence of xylem cell death and discolouration was detectable within 12 h and vessel tyloses were present after 3 days. Concentration of tetra-galloylglucose increased by 3 . 5-fold within 24 h, while the trend for total phenols was a slow increase reaching a maximum after 21 days. Suberin was not detected. Early accumulation of water content has been proposed as a defence component of host± pathogen interactions in woody angiosperm xylem, but this was not obvious for E. nitens. Nuclear magnetic resonance imaging (NMR imaging or MRI) was used to measure small-scale distributions in moisture content around the inoculated stem wounds in intact E. nitens saplings. Some moisture accumulation was detectable at lesion margins of wounds analysed after 3 weeks. However, this was not detectable by gravimetric measurements. This increase in moisture content may be a consequence of wound physiology rather than an active defence response. *
Analysis of the link between injuries on forest trees and presence of harmful fungal organisms
Scientific Research and Essays, 2013
This research focus on the occurrence of pathogenic microorganisms on beech trees relative to the presence of tree injuries, with the aim to ensure protection and preservation of this species in Serbia. The research was conducted in eastern Serbia, in a hillside beech forest Fagetum moesiacae submontanum of generative origin. The testing was carried out on two sites over 51 testing plots, with a total of 829 trees and 21 species of identified fungi. On the first site it was found that the appearance of fungi primarily depends on the presence of mechanical damage on trees (as much as 73.46%), while the presence of abiotic damage has almost no bearing (only 3.21%). On the second site there was a strong correlation link between the occurrence of fungi and presence of mechanical damage 51.88%, as well as between the fungi and abiotic damage – 47.96%. The health condition of high beech stands was found to be heavily dependent on careful and proper manipulation during harvesting, while ea...