Teija Ruuhola - Academia.edu (original) (raw)

Papers by Teija Ruuhola

Research paper thumbnail of Communicated by Evan DeLucia

of elevated ultraviolet-B radiation on a plant–herbivore interaction

Research paper thumbnail of RESEARCH ARTICLE Asynchrony between Host Plant and Insects- Defoliator within a Tritrophic System: The Role of Herbivore Innate Immunity

The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host pl... more The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects ’ fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenom-enon. However, the spreading of this phenomenon through the food chain, and especially those mechanisms operating this spreading, are still unclear. In this paper, we study the effect of seasonally declined leafquality (estimated in terms of phenolics and nitrogen con-tent) on herbivore fitness, immune parameters and resistance against pathogen by using the silver birch Betula pendula—gypsy moth Lymantria dispar—nucleopolyhedrovirus as the tritrophic system. We show that a phenological mismatch induced by the delay in the emergence of gypsy moth larvae and following feeding on mature leaves has negative effects on the female pupal weight, on the rate of larval development and on the activity of phenoloxidase in the p...

Research paper thumbnail of Effects of long-term UV-exposure and plant sex on the leaf phenoloxidase activities and phenolic concentrations of Salix myrsinifolia (Salisb.)

Plant physiology and biochemistry : PPB, 2018

The accumulation of flavonoids on the leaf surface is a well-characterized protective mechanism a... more The accumulation of flavonoids on the leaf surface is a well-characterized protective mechanism against UV-B radiation. Other protective mechanisms, such as the induction of antioxidative enzymes and peroxidase-mediated lignification may also be important. The effects of UV-B radiation have mainly been considered in short-term studies, whereas ecologically more relevant long-term field studies are still rare. Here we examined the effects of long-term exposure to enhanced UV-B radiation on the activities of two antioxidative enzymes, polyphenol oxidase (PPO; EC 1.10.2.2 and EC 1.14.18.1) and guaiacol peroxidase (POD; EC 1.11.1.7), as well as the phenolic concentrations in two sexes of the dioecious species, Salix myrsinifolia. After three consecutive growth seasons with enhanced UV-B radiation, we found that PPO activity was decreased by UV radiation in male plants, which might explain their lower UV-B tolerance when compared to female plants. In addition, male plants had higher spec...

Research paper thumbnail of Effects of Cd2+ exposure on key life history traits and activities of four metabolic enzymes in Helicoverpa armigera (Lepidopteran: Noctuidae)

Chemistry and Ecology, 2017

Research paper thumbnail of Amino acids during development of mountain birch leaves

Research paper thumbnail of Dynamics of salicylates in willows and its relationship to herbivory

Research paper thumbnail of Foliar Phenolics are Differently Associated with Epirrita autumnata Growth and Immunocompetence

Journal of Chemical Ecology, 2007

Research paper thumbnail of Kallioperä ja maalaji vaikuttavat hirvivahinkojen määrään

Metsätieteen aikakauskirja, 2016

Research paper thumbnail of Pajujen salisylaattien dynamiikka ja sen suhde hyönteisvaurioihin

Research paper thumbnail of Ellagitannins: defences of Betula nana against Epirrita autumnata folivory?

Agricultural and Forest Entomology, 2013

Research paper thumbnail of DIFFERENCES IN HOST USE EFFICIENCY OF LARVAE OF A GENERALIST MOTH,Operophtera brumata ON THREE CHEMICALLY DIVERGENTSalix SPECIES

Research paper thumbnail of In Vitro Degradation of Willow Salicylates

Journal of Chemical Ecology, Apr 30, 2003

Research paper thumbnail of Temperature as a Modifier of Plant–Herbivore Interaction

Journal of Chemical Ecology, Feb 1, 2007

Research paper thumbnail of Effects of elevated ultraviolet-B radiation on a plant�herbivore interaction

Research paper thumbnail of Trade-off between synthesis of salicylates and growth of micropropagated Salix pentandra

Journal of Chemical Ecology, Jan 6, 2003

Research paper thumbnail of Systemic Induction of Salicylates in Salix myrsinifolia(Salisb.)

Research paper thumbnail of Do ectomycorrhizas affect boron uptake in Betula pendula ?

Canadian Journal of Forest Research, 2014

Research paper thumbnail of In vitro degradation of willow salicylates

Journal of chemical ecology, 2003

Salicylates are defensive compounds against a great variety of generalist herbivores. Salicortin ... more Salicylates are defensive compounds against a great variety of generalist herbivores. Salicortin and its derivatives are labile compounds that degrade immediately when cell compartmentalization is ruptured, producing a 6-hydroxy-2-cyclohexenone (6-HCH) moiety that is a strong antifeeding cue. We studied the in vitro degradation of willow salicylates in the presence and absence of foliar enzymes at acidic, neutral, and alkaline pHs. Higher substituted salicylates were degraded in the absence of foliar enzymes at alkaline pH and in the presence of foliar enzymes at all three pHs. Salicin and its diglucoside, on the other hand, were degraded only in the presence of foliar enzymes at acidic pH, probably by beta-glucosidase activity. The main degradation products of higher substituted salicylates were salicin, 6-HCH, and catechol in both the absence and presence of enzymes, suggesting that the production of 6-HCH and catechol do not necessarily demand enzymatic activity. We propose that ...

Research paper thumbnail of 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 pubes... more 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...

Research paper thumbnail of Trade-off between synthesis of salicylates and growth of micropropagated Salix pentandra

Journal of chemical ecology, 2003

We studied the relationship between biosynthesis of salicylates, the main chemical defenses in wi... more We studied the relationship between biosynthesis of salicylates, the main chemical defenses in willow and growth of Salix pentandra by cultivating plants in the presence of 2-aminoindan-2-phosphonic acid (AIP), a powerful inhibitor of phenylalanine ammonia-lyase (PAL: EC 4.3.1.5.). AIP inhibited efficiently, though not totally, the endogenous synthesis of salicylates. This inhibition markedly increased plant growth. Exogenous application of the precursors of salicylates, benzoic acid (BA), salicylic acid (SA), and helicin, increased the levels of several individual salicylates, but decreased the growth of plants cultivated in the presence of AIP. These results suggest a trade-off between plant growth and the synthesis of salicylates in S. pentandra. Phenylalanine, which accumulated in response to inhibitor treatment, but was decreased by precursor treatments, may be a common and limiting precursor for both plant growth and salicylate synthesis. The biosynthesis of salicin is suggest...

Research paper thumbnail of Communicated by Evan DeLucia

of elevated ultraviolet-B radiation on a plant–herbivore interaction

Research paper thumbnail of RESEARCH ARTICLE Asynchrony between Host Plant and Insects- Defoliator within a Tritrophic System: The Role of Herbivore Innate Immunity

The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host pl... more The effects of asynchrony in the phenology of spring-feeding insect-defoliators and their host plants on insects ’ fitness, as well as the importance of this effect for the population dynamics of outbreaking species of insects, is a widespread and well-documented phenom-enon. However, the spreading of this phenomenon through the food chain, and especially those mechanisms operating this spreading, are still unclear. In this paper, we study the effect of seasonally declined leafquality (estimated in terms of phenolics and nitrogen con-tent) on herbivore fitness, immune parameters and resistance against pathogen by using the silver birch Betula pendula—gypsy moth Lymantria dispar—nucleopolyhedrovirus as the tritrophic system. We show that a phenological mismatch induced by the delay in the emergence of gypsy moth larvae and following feeding on mature leaves has negative effects on the female pupal weight, on the rate of larval development and on the activity of phenoloxidase in the p...

Research paper thumbnail of Effects of long-term UV-exposure and plant sex on the leaf phenoloxidase activities and phenolic concentrations of Salix myrsinifolia (Salisb.)

Plant physiology and biochemistry : PPB, 2018

The accumulation of flavonoids on the leaf surface is a well-characterized protective mechanism a... more The accumulation of flavonoids on the leaf surface is a well-characterized protective mechanism against UV-B radiation. Other protective mechanisms, such as the induction of antioxidative enzymes and peroxidase-mediated lignification may also be important. The effects of UV-B radiation have mainly been considered in short-term studies, whereas ecologically more relevant long-term field studies are still rare. Here we examined the effects of long-term exposure to enhanced UV-B radiation on the activities of two antioxidative enzymes, polyphenol oxidase (PPO; EC 1.10.2.2 and EC 1.14.18.1) and guaiacol peroxidase (POD; EC 1.11.1.7), as well as the phenolic concentrations in two sexes of the dioecious species, Salix myrsinifolia. After three consecutive growth seasons with enhanced UV-B radiation, we found that PPO activity was decreased by UV radiation in male plants, which might explain their lower UV-B tolerance when compared to female plants. In addition, male plants had higher spec...

Research paper thumbnail of Effects of Cd2+ exposure on key life history traits and activities of four metabolic enzymes in Helicoverpa armigera (Lepidopteran: Noctuidae)

Chemistry and Ecology, 2017

Research paper thumbnail of Amino acids during development of mountain birch leaves

Research paper thumbnail of Dynamics of salicylates in willows and its relationship to herbivory

Research paper thumbnail of Foliar Phenolics are Differently Associated with Epirrita autumnata Growth and Immunocompetence

Journal of Chemical Ecology, 2007

Research paper thumbnail of Kallioperä ja maalaji vaikuttavat hirvivahinkojen määrään

Metsätieteen aikakauskirja, 2016

Research paper thumbnail of Pajujen salisylaattien dynamiikka ja sen suhde hyönteisvaurioihin

Research paper thumbnail of Ellagitannins: defences of Betula nana against Epirrita autumnata folivory?

Agricultural and Forest Entomology, 2013

Research paper thumbnail of DIFFERENCES IN HOST USE EFFICIENCY OF LARVAE OF A GENERALIST MOTH,Operophtera brumata ON THREE CHEMICALLY DIVERGENTSalix SPECIES

Research paper thumbnail of In Vitro Degradation of Willow Salicylates

Journal of Chemical Ecology, Apr 30, 2003

Research paper thumbnail of Temperature as a Modifier of Plant–Herbivore Interaction

Journal of Chemical Ecology, Feb 1, 2007

Research paper thumbnail of Effects of elevated ultraviolet-B radiation on a plant�herbivore interaction

Research paper thumbnail of Trade-off between synthesis of salicylates and growth of micropropagated Salix pentandra

Journal of Chemical Ecology, Jan 6, 2003

Research paper thumbnail of Systemic Induction of Salicylates in Salix myrsinifolia(Salisb.)

Research paper thumbnail of Do ectomycorrhizas affect boron uptake in Betula pendula ?

Canadian Journal of Forest Research, 2014

Research paper thumbnail of In vitro degradation of willow salicylates

Journal of chemical ecology, 2003

Salicylates are defensive compounds against a great variety of generalist herbivores. Salicortin ... more Salicylates are defensive compounds against a great variety of generalist herbivores. Salicortin and its derivatives are labile compounds that degrade immediately when cell compartmentalization is ruptured, producing a 6-hydroxy-2-cyclohexenone (6-HCH) moiety that is a strong antifeeding cue. We studied the in vitro degradation of willow salicylates in the presence and absence of foliar enzymes at acidic, neutral, and alkaline pHs. Higher substituted salicylates were degraded in the absence of foliar enzymes at alkaline pH and in the presence of foliar enzymes at all three pHs. Salicin and its diglucoside, on the other hand, were degraded only in the presence of foliar enzymes at acidic pH, probably by beta-glucosidase activity. The main degradation products of higher substituted salicylates were salicin, 6-HCH, and catechol in both the absence and presence of enzymes, suggesting that the production of 6-HCH and catechol do not necessarily demand enzymatic activity. We propose that ...

Research paper thumbnail of 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 pubes... more 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...

Research paper thumbnail of Trade-off between synthesis of salicylates and growth of micropropagated Salix pentandra

Journal of chemical ecology, 2003

We studied the relationship between biosynthesis of salicylates, the main chemical defenses in wi... more We studied the relationship between biosynthesis of salicylates, the main chemical defenses in willow and growth of Salix pentandra by cultivating plants in the presence of 2-aminoindan-2-phosphonic acid (AIP), a powerful inhibitor of phenylalanine ammonia-lyase (PAL: EC 4.3.1.5.). AIP inhibited efficiently, though not totally, the endogenous synthesis of salicylates. This inhibition markedly increased plant growth. Exogenous application of the precursors of salicylates, benzoic acid (BA), salicylic acid (SA), and helicin, increased the levels of several individual salicylates, but decreased the growth of plants cultivated in the presence of AIP. These results suggest a trade-off between plant growth and the synthesis of salicylates in S. pentandra. Phenylalanine, which accumulated in response to inhibitor treatment, but was decreased by precursor treatments, may be a common and limiting precursor for both plant growth and salicylate synthesis. The biosynthesis of salicin is suggest...