Characterization of wound responses of stems of paper birch (Betula papyrifera) and European white birch (Betula pendula) (original) (raw)
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2001
We investigated the role of phenolic and phenolic-related traits of the leaves of mountain birch (Betula pubescens ssp. czerepanovii) as determinants of their suitability for the growth of larvae of the geometrid Epirrita autumnata. As parameters of leaf suitability, we determined the contents of total phenolics, gallotannins, soluble and cell-wall-bound proanthocyanidins (PAS and PAB, respectively), lignin, protein precipitation capacity of tannins (PPC), and leaf toughness.
Induced Defense in Japanese White Birch Seedlings against Insect Herbivores
Eurasian Journal of …, 2010
Plants defend themselves against herbivores, pests and abiotic stresses. Although some defense traits in plants are constitutive, some are switched on, or increased, only when the plants have suffered from stresses (i.e. induced defense). Growth (i.e. lignin) and the synthesis of most defensive compounds in broad-leaved trees derive from phenylalanine. If, therefore, plants allocate photosynthates mainly to defense, these resources would not be available for growth (lignin synthesis). In this study, we examined the defense induced against grazing by the gypsy moth (Lymantria dispar) in seedlings of the white birch (Betula platyphylla var. japonica) grown under two nitrogen levels. We exposed white birch leaves to be grazed by gypsy moths, and we cut the leaves with scissors in early spring. The defenses of white birch seedlings, especially the amount of total phenolics and condensed tannin, were found to be induced by cutting, to extents that were influenced by the soil nitrogen condition. Induced defense of white birch seedlings may depend on the heterophyllous type of shoot development.
2006
The different defence strategies of trees against herbivores are very often connected with succession status, leaf life span and the level of secondary metabolites. We examined the effect of simulated leaf grazing on the differences in the leaf life span and defence chemistry of two pioneer tree species that belongs to the same family (Betulaceae), black alder (Alnus glutinosa (L.) Gaertn.) and European white birch (Betula pendula Roth.). At the beginning of the growing season, mature leaves were perforated using a paper punch. The holes removed about 10% of the leaf surface. Each species was represented by six trees-one branch was chosen for perforation and one branch as a control. All leaves were counted every week until their abscission. Additional damages caused by grazing insects were also noted. Undamaged birch leaves were held much longer than those of alder. The average difference in half leaf life span between control and perforated leaves was 28 days in birch and 6 days in alder. The control unperforated alder leaves were significantly (P <0.05) more often grazed by insects than those that were perforated. Leaf perforation in alder increase phenolic concentrations in the new, young leaves. In birch we did not observe these changes. The comparison of alder and birch indicate that the species with similar successional status can have different strategies of leaf defence. The birch leaves were characterized by a longer leaf life span, constitutive defence, a lack of induced defence accumulation of phenolics and earlier shedding of damaged leaves in comparison to the control. The black alder foliage had a shorter leaf life span, induced defence reaction (produced more phenolics after perforation), and only slightly earlier shedding of damaged leaves than the control.
Received 8 February 2013 There is increasing evidence that plants can react to biotic aggressions with highly specific responses. However, few studies have attempted to jointly investigate whether the induction of plant defences is specific to a targeted plant tissue, plant species, herbivore identity, and defensive trait. Here we studied those factors contributing to the specificity of induced defensive responses in two economically impor- tant pine species against two chewing insect pest herbivores. Juvenile trees of Pinus pinaster and P. radiata were exposed to herbivory by two major pest threats, the large pine weevil Hylobius abietis (a bark-fee- der) and the pine processionary caterpillar Thaumetopoea pityocampa (a folivore). We quantified in two tissues (stem and needles) the constitutive (control plants) and herbivore-induced concentrations of total polyphenolics, volatile and non-volatile resin, as well as the profile of mono- and sesquiterpenes. Stem chewing by the pine weevil increased concentrations of non-volatile resin, volatile monoterpenes, and (marginally) polyphenolics in stem tissues. Weevil feeding also increased the concentration of non-vol- atile resin and decreased polyphenolics in the needle tissues. Folivory by the caterpillar had no major effects on needle defensive chemistry, but a strong increase in the concentration of polyphenolics in the stem. Interestingly, we found similar patterns for all these above-reported effects in both pine spe- cies. These results offer convincing evidence that induced defences are highly specific and may vary depending on the targeted plant tissue, the insect herbivore causing the damage and the considered defensive compound.
Polish Journal of Ecology
The different defence strategies of trees against herbivores are very often connected with succession status, leaf life span and the level of secondary metabolites. We examined the effect of simulated leaf grazing on the differences in the leaf life span and defence chemistry of two pioneer tree species that belongs to the same family (Betulaceae), black alder (Alnus glutinosa (L.) Gaertn.) and European white birch (Betula pen-dula Roth.). At the beginning of the growing season , mature leaves were perforated using a paper punch. The holes removed about 10% of the leaf surface. Each species was represented by six trees – one branch was chosen for perforation and one branch as a control. All leaves were counted every week until their abscission. Additional damages caused by grazing insects were also noted. Undamaged birch leaves were held much longer than those of alder. The average difference in half leaf life span between control and perforated leaves was 28 days in birch and 6 day...
Plant Defense Characteristics and Hypotheses in Birch Species
Eurasian Journal of Forest Research, 2010
Birches employ defense when under pressure, either biotic or abiotic or both. They have at least three types of defense against herbivores, involving physical, chemical and phenological strategies, whether the defense is constitutive or induced. Leaves usually use both types of defense, whereas woody parts (stems, branches, or twigs) deploy mostly chemical defense. Other studies scarcely differentiate between proposed plant defense models such as CNBH and GDBH, and the defensive responses of birches, since there is a large variation in defensive responses. The evidence supports neither the carbon-nutrient balance (CNB) nor the growth-differentiation balance (GDB) hypothesis in birch defense, indicating that defense is genetically regulated. In our review, we may conclude that birches deploy their various defenses in parallel, since these derive from distinct chemical and physical mechanisms.
Wound-induced oxidative responses in mountain birch leaves
Annals of botany, 2006
The aim of the study was to examine oxidative responses in subarctic mountain birch, Betula pubescens subsp. czerepanovii, induced by herbivory and manual wounding. Herbivory-induced changes in polyphenoloxidase, peroxidase and catalase activities in birch leaves were determined. A cytochemical dye, 3,3-diaminobenzidine, was used for the in situ and in vivo detection of H2O2 accumulation as a response to herbivory and wounding. To localize peroxidase activity in leaves, 10 mm H2O2 was applied to the dye reagent. Feeding by autumnal moth, Epirrita autumnata, larvae caused an induction in polyphenoloxidase and peroxidase activities within 24 h, and a concomitant decrease in the activity of antioxidative catalases in wounded leaves. Wounding also induced H2O2 accumulation, which may have both direct and indirect defensive properties against herbivores. Wound sites and guard cells showed a high level of peroxidase activity, which may efficiently restrict invasion by micro-organisms. Bir...
Variable responses of folivorous sawflies to leaf quality of mountain birch
Canadian Journal of Forest Research, 2005
We studied whether the larval performance of four sawfly species feeding on mountain birch (Betula pubescens subsp. czerepanovii (Orlova) Hämet-Ahti) leaves at different times of the growing season was related to the same chemical and physical leaf traits. In the three phenologically earliest species, larval growth was related to the same set of leaf traits. In contrast, consumption of leaf material was related to different leaf traits in all of the four species. Leaf suitability for herbivore growth and tree resistance to herbivore consumption were thus not always determined by the same leaf traits. Leaf water content and toughness had the strongest associations with larval performance. Phenolics, which are often considered the main resistance compounds in deciduous trees, explained only a small part of the variance in leaf consumption, but some groups of phenolics were negatively related to larval growth. In conclusion, the same mountain birch trees were not resistant to all of th...
Trees-structure and Function, 2005
Previous studies on the mechanisms of birch resistance to herbivores and foliar micro-fungi (both pathogenic and endophytic) have focused mainly on the role of internal leaf chemistry. In the present study, we examined genetic correlations between leaf surface traits (glandular trichome density and total concentrations of surface flavonoid aglycones) and occurrence of three species of foliar micro-fungi, one pathogenic rust (Melampsoridium betulinum) and two endophytic fungi (Fusicladium sp. and Melanconium sp.), and performance of autumnal moth larvae (Epirrita autumnata) in two birch species, Betula pubescens ssp. czerepanovii and B. pendula. The performance of autumnal moth larvae on B. pubescens ssp. czerepanovii was negatively correlated with density of glandular trichomes (RGR: r=−0.855; pupal mass: r=−0.709). In addition, rust infection was negatively correlated with trichome density in B. pendula (r=−0.675) and with epicuticular flavonoid aglycones in B. pubescens ssp. czerepanovii (r=−0.855). The frequency of the endophytic fungus Fusicladium sp., was related to epicuticular flavonoid aglycones (r=−0.782), while another endophytic fungus, Melanconium sp., showed no associations with any of the studied variables in B. pubescens ssp. czerepanovii. Our results indicate that leaf surface traits may be at least as important determinants of herbivore performance and micro-fungi abundance in birch as leaf internal chemistry.