Fine roots of Picea abies compensate for drought stress in the rainfall reduction experiment

This study evaluates the influence of repeated artificial drought stress on the fine root charac- teristics – including ectomycorrhizae – of Norway spruce [Picea abies (L.) Karst]. The experimental site consisted of two plots in a mature spruce monoculture stand. The water regime at parts of both plots was regulated by shelters and an isolation trench during vegetation season (spring to autumn) since 2010. Root samples were collected during autumn in 2010, 2012, and 2013. Root analyses revealed the effect of drought stress on mycorrhizal root tips changed over time. While a density of active mycorrhizae was about 34% lower in drought-stressed areas compared to nonstressed (control) areas in 2010, it increased by 15% in 2012 and by 22% in 2013 over both plots. We observed the less pronounced effect of drought on a proportion of active mycorrhizae, but it generally followed the pattern of active mycorrhizae density. The density of nonactive mycorrhizae was not influenced by drought but significantly fluctuated during the course of the experiment. Other root characteristics such as the dry mass of fine roots (< 1 mm), the specific length of fine roots (< 1 mm) and the composition of the ectomycorrhizal community (primarily dominated by Amphinema byssoides, Tylospora fibrillosa, Tylopilus felleus, and Cenococcum geophilum) were also not significantly influenced by drought. Our results indicate the ability of Norway spruce fine roots to com- pensate for repeated drought stress of the intermediate intensity

Overview of development of an anti-attractant based technology for spruce protection against Ips typographus: From past failures to future success

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Acute and regular exercise distinctly modulate serum, plasma and skeletal muscle BDNF in the elderly

Brain-derived neurotrophic factor (BDNF) participates in orchestrating the adaptive response to exercise. However, the importance of transient changes in circulating BDNF for eliciting whole-body and skeletal muscle exercise benefits in humans remains relatively unexplored. Here, we investigated effects of acute aerobic exercise and 3-month aerobic-strength training on serum, plasma and skeletal muscle BDNF in twenty-two sedentary older individuals (69.0 ± 8.0 yrs., 9 M/13F). BDNF response to acute exercise was additionally evaluated in young trained individuals (25.1 ± 2.1 yrs., 3 M/5F). Acute aerobic exercise transiently increased serum BDNF in sedentary (16%, p = .007) but not in trained elderly or young individuals. Resting serum or plasma BDNF was not regulated by exercise training in the elderly. However, subtle training-related changes of serum BDNF positively correlated with improvements in walking speed (R = 0.59, p = .005), muscle mass (R = 0.43, p = .04) and cognitive performance (R = 0.41, p = .05) and negatively with changes in body fat (R = -0.43, p = .04) and triglyceridemia (R = -0.53, p = .01). Individuals who increased muscle BDNF protein in response to 3-month training (responders) displayed stronger acute exercise-induced increase in serum BDNF than non-responders (p = .006). In addition, muscle BDNF protein content positively correlated with type II-to-type I muscle fiber ratio (R = 0.587, p = .008) and with the rate of post-exercise muscle ATP re-synthesis (R = 0.703, p = .005). Contrary to serum, acute aerobic exercise resulted in a decline of plasma BDNF 1 h post-exercise in both elderly-trained (-34%, p = .002) and young-trained individuals (-48%, p = .034). Acute circulating BDNF regulation by exercise was dependent on the level of physical fitness and correlated with training-induced improvements in metabolic and cognitive functions. Our observations provide an indirect evidence that distinct exercise-induced changes in serum and plasma BDNF as well as training-related increase in muscle BDNF protein, paralleled by improvements in muscle and whole-body clinical phenotypes, are involved in the coordinated adaptive response to exercise in humans

Acute and regular exercise distinctly modulate serum, plasma and skeletal muscle BDNF in the elderly

Brain-derived neurotrophic factor (BDNF) participates in orchestrating the adaptive response to exercise. However, the importance of transient changes in circulating BDNF for eliciting whole-body and skeletal muscle exercise benefits in humans remains relatively unexplored. Here, we investigated effects of acute aerobic exercise and 3-month aerobic-strength training on serum, plasma and skeletal muscle BDNF in twenty-two sedentary older individuals (69.0 ± 8.0 yrs., 9 M/13F). BDNF response to acute exercise was additionally evaluated in young trained individuals (25.1 ± 2.1 yrs., 3 M/5F). Acute aerobic exercise transiently increased serum BDNF in sedentary (16%, p = .007) but not in trained elderly or young individuals. Resting serum or plasma BDNF was not regulated by exercise training in the elderly. However, subtle training-related changes of serum BDNF positively correlated with improvements in walking speed (R = 0.59, p = .005), muscle mass (R = 0.43, p = .04) and cognitive performance (R = 0.41, p = .05) and negatively with changes in body fat (R = -0.43, p = .04) and triglyceridemia (R = -0.53, p = .01). Individuals who increased muscle BDNF protein in response to 3-month training (responders) displayed stronger acute exercise-induced increase in serum BDNF than non-responders (p = .006). In addition, muscle BDNF protein content positively correlated with type II-to-type I muscle fiber ratio (R = 0.587, p = .008) and with the rate of post-exercise muscle ATP re-synthesis (R = 0.703, p = .005). Contrary to serum, acute aerobic exercise resulted in a decline of plasma BDNF 1 h post-exercise in both elderly-trained (-34%, p = .002) and young-trained individuals (-48%, p = .034). Acute circulating BDNF regulation by exercise was dependent on the level of physical fitness and correlated with training-induced improvements in metabolic and cognitive functions. Our observations provide an indirect evidence that distinct exercise-induced changes in serum and plasma BDNF as well as training-related increase in muscle BDNF protein, paralleled by improvements in muscle and whole-body clinical phenotypes, are involved in the coordinated adaptive response to exercise in humans

Do Water-Limiting Conditions Predispose Norway Spruce to Bark Beetle Attack?

Drought is considered to enhance susceptibility of Norway spruce (Picea abies) to infestations by the Eurasian spruce bark beetle (Ips typographus, Coleoptera: Curculionidae), although empirical evidence is scarce. We studied the impact of experimentally induced drought on tree water status and constitutive resin flow, and how physiological stress affects host acceptance and resistance. We established rain‐out shelters to induce both severe (two full‐cover plots) and moderate (two semi‐cover plots) drought stress. In total, 18 sample trees, which were divided equally between the above treatment plots and two control plots, were investigated. Infestation was controlled experimentally using a novel ‘attack box’ method. Treatments influenced the ratios of successful and defended attacks, but predisposition of trees to infestation appeared to be mainly driven by variations in stress status of the individual trees over time. With increasingly negative twig water potentials and decreasing resin exudation, the defence capability of the spruce trees decreased. We provide empirical evidence that water‐limiting conditions impair Norway spruce resistance to bark beetle attack. Yet, at the same time our data point to reduced host acceptance by I. typographus with more extreme drought stress, indicated by strongly negative pre‐dawn twig water potentials