Contents:
Trends in Plant Science Messages from novel phytotron and free-air fumigation studies. From forest decline to multiple-stress effects on forest ecosystem services. Nikolova P, Hanke D. Enhanced ozone strongly reduces carbon sink strength of adult beech Fagus sylvatica - Resume from the free-air fumigation study at Kranzberg Forest.
Gefahrstoffe — Reinhaltung der Luft Ritter W, Andersen C. Gaps in understanding and future directions for research. Atmospheric Chemistry and Physics A Challenge in Plant Science. Ecological Studies , Springer, pp. Growth and Defence in Plants. Matyssek R Conclusions and Perspectives. Tree Physiol 32 Defence in European Beech Fagus sylvatica L. Resource Allocation at Multiple Scales.
Nova Acta Leopoldina-Jahrbuch The Alternatives Growth and Defence: Resource Allocation at Multiple Scales in Plants. Nova Acta Leopoldina Tausz M, Grulke N. Trees in a Changing Environment: Ecophysiology, Adaptation and Future Survival, Springer, in press. The Processes — Competition versus Facilitation. European Journal of Forest Research doi: Plant, Cell and Environment doi: Forest Ecology and Management Understanding and Perspectives from Forest Research.
Developments in Environmental Science 13, Elsevier, pp. Lessons from the free-air canopy fumigation experiment at Kranzberg Forest.
Short-term and long-term effects on growth and hysiological performance of Norway spruce Picea abies. The carbon balances of three deciduous larch species and an evergreen spruce species near Bayreuth W. Turner H and Tranquillini W eds. Establishment and Tending of Subalpine Forests: Der Stellenwert der Bioindikationsforschung. Tesche M, Feiler S eds. Air pollution and tree ecophysiology. Long-term implications of climate change and air pollution on forest ecosystems.
Lesnictvi - Forestry Ausgangsbasis, Erfordernisse und Perspektiven. Paivinen R, Schuck A eds. From chamber experiments to the conditions of mixed forest stands. Radoglu K, Huttunen S eds. Different pathways through life - biochemical aspects of plant biology and medicine. The indicative value of AOT Fuhrer J, Achermann B eds. News Forschungsgemeinschaft Funk, 7 3: Matyssek R, Blaschke H Testing growth chambers: The distribution of light, temperature and air humidity in walk-in chambers.
A case study in a controlled chamber environment. Kosten und Nutzen von Raumbesetzung und —ausbeutung. AFZ — der Wald Canopy research in a temperate mixed forest of Southern Germany. Studying Forest Canopies from above: The international canopy crane network. Wieser G, Tausz M eds. Critical Levels of Ozone: Ozone sensitivity of plants is determined by biochemical amplification or down-regulation.
Experimental risk assessment of mitigation by chronic ozone impact. Verlag Grauer, Beuren, Stuttgart, p. A comparison beech and spruce. Verlag Grauer, Beuren, Stuttgart, pp.
Forstarchiv 81, Heft 2: Bericht zu Leopoldina-Symposium LWF aktuell Forstliche Klimaforschung While it may seem obvious that studies of plant defences should be focused on chemical, physical and anatomical traits that clearly serve a defensive role, a large number of commonly measured traits appear to be poor indicators of defence and resistance on larger scales Carmona et al. It is against this backdrop that Moreira et al. Roughly 7 months after germination, and 2 weeks after methyl jasmonate treatments were applied to simulate herbivore attack, the authors measured tree growth height and biomass and harvested the trees to measure resin duct characteristics total number and size in various regions of each seedling.
The authors not only looked for phenotypic responses to both P-limitation and methyl jasmonate treatments, but also for genetic influences on treatment responses that might indicate a role of heritable, locally adaptive trade-offs between resource availability and tree growth and defence. Similar to P-limitation, simulated herbivory methyl jasmonate application also led to a significant, but less pronounced reduction in biomass, and an increase in resin duct density and area Figure 1.
While both treatments led to changes in resin duct characteristics, when simulated herbivory took place under P-limitation it spurred a dramatic increase in resin duct defences, with genetic provenance having a strong influence on the response Figure 1. Illustrated results from Moreira et al. Variation in tree size and in the number and size of resin ducts in the stem cross-sections shown here are proportional to changes in biomass and resin duct characteristics reported by the authors.
Phosphorus-limiting treatments are shown on the right yellow half of the illustration. These results support the existence of a trade-off among growth and defence in the juvenile stages of this relatively long-lived pine species. Specifically, the production of resin ducts was costly regardless of resource availability, as indicated by the additional decrease in growth rates caused by the increase in resin ducts under simulated herbivory. The study also offers mixed support for the RAH since resource limitation did lead to greater constitutive defences at the expense of growth as predicted by the hypothesis.
However, there was a far greater increase in induced defences, which is not expected under the RAH. At the same time, the study would seem to offer more support for the GDBH as the reduction in growth seen under P-limitation was accompanied by greater differentiation of both constitutive and inducible resin duct cells indicating an overall defense response to resource availability. A similar pattern was found for the chemical defences of the same seedlings used by Moreira et al.
Specifically, P-limitation increased the chemical concentration of both constitutive and induced resin in P. The greater induction of resin ducts under key nutrient limitation alone would be interesting enough to draw attention to their study, but Moreira et al.
This genetic effect on tree responses to resource availability and herbivory has important implications as it demonstrates that differences in defence phenotypes within a species can be due to heritable variation and is not simply plasticity in the face of environmental gradients. This finding is of note because it indicates that plant defence expression in response to resource limitation and herbivory is contextually adaptive.
In other words, the evidence of strong genetic influences on the number and size of resin ducts induced among openly pollinated P. Conifers, including pines, are known to be locally adapted to climate and edaphic properties even in cases where gene flow among populations is present e. Likewise, resin defence traits such as chemical profile, flow rates and resin duct characteristics have been demonstrated as heritable Strom et al.
Thus, given their influence on fitness—either from benefits of protecting plants from attack, or through trade-off costs with other key functions—variation in resin defence phenotypes within and across species is likely to be adaptive to selection pressures from local environments and biotic interactions Agrawal This scenario might explain the mixed support that various plant defence theories have garnered, but also highlights a need to further integrate plant defence studies with the geographic mosaic theory, which posits that natural selection pressures vary among populations due to changes in biotic communities and environments Thompson To the extent that number and size of resin ducts influence components of fitness such as growth, survival and reproduction, these responses define selection pressures driving the evolution of tree defences.
While P-limitation had a positive effect on resin duct size and density as reported by Moreira et al. Conversely, Wimmer and Grabner found that resin duct numbers in Picea abies Karst decreased with above average growing-season precipitation, but increased in years with above average growing-season temperatures, suggesting an important influence of the timing of stresses and resource availability on resin duct production and characteristics. A number of studies have also found a positive relationship between tree growth and resin duct production in annual xylem rings of mature trees in several species of pines including: Kane and Kolb , P.
As discussed above, Moreira et al. Finally, strong evidence that natural enemies exert selection pressure on resin duct traits comes from Kane and Kolb , who found that tree-killing bark beetles selectively attacked P. Conceptual hierarchy of factors experimentally demonstrated to influence resin duct number and size within individuals and populations in various species of conifers.
Wimmer and Grabner reported positive effects of above average temperatures during the growing season on resin duct production, while finding negative effects of above average precipitation. A positive relationship between tree growth and resin duct production was found in P. In addition to the P. Strong selection pressure exerted by tree-killing bark beetles against trees with fewer or smaller resin ducts was reported by Kane and Kolb and Ferrenberg et al.
The mounting evidence that resin ducts are an important defence in pines and other conifers justifies the continued use of these traits in plant defence hypothesis testing; however, a number of key gaps exist in our understanding of these traits and their defence roles. Specifically, changes in resin duct allocation, size and effectiveness against natural enemies across stages of phenology and ontogeny are likely and require investigation among species and environments Boege and Marquis , Barton and Koricheva , Muola et al.
These defences might also vary in relation to other anatomical defence mechanisms that can dramatically reduce natural enemy attack density on conifers e.
A Lattanzi 8 Solar radiation as a driver for growth and competition in forest stands M. This genetic effect on tree responses to resource availability and herbivory has important implications as it demonstrates that differences in defence phenotypes within a species can be due to heritable variation and is not simply plasticity in the face of environmental gradients. A positive relationship between tree growth and resin duct production was found in P. While it may seem obvious that studies of plant defences should be focused on chemical, physical and anatomical traits that clearly serve a defensive role, a large number of commonly measured traits appear to be poor indicators of defence and resistance on larger scales Carmona et al. Eur J Forest Res This finding is of note because it indicates that plant defence expression in response to resource limitation and herbivory is contextually adaptive. Matyssek 18 Effects of stress and defence allocation on tree growth - simulation results at the individual and stand level T.
As shown under greenhouse conditions by Moreira et al. For example, how might the results of Moreira et al. Variation in both evolutionary and ecological processes across the landscape have likely generated a mosaic of functional trade-offs within and among conifer species.
Plants use resources, i.e. carbon, nutrients, water and energy, either for growth or to This volume provides a timely understanding of resource allocation and its regulation in plants, linking the molecular with Resource Allocation at Multiple Scales . Series Title: Ecological Studies; Series Volume: ; Copyright: Growth and Defence in Plants Resource Allocation at Multiple Scales. Book · January with 60 Reads. Publisher: Ecological Studies Publisher.
While it may seem daunting to consider all sources of variation in experimental studies, the examples of Rosner and Hannrup , Sampedro et al. Even as we collectively and incrementally move toward a more nuanced, dynamic framework of plant defences, it is necessary to verify that presumed defence traits have measurable influences on plant fitness in the face of various natural enemy communities. This key step is often neglected in favour of interspecific or cross-system comparisons of specific secondary chemicals e.
As noted by Gould and Lewontin , who cautioned against viewing existing phenotypes as resulting from improvements through selection: The solution followed in any spot is a result of history; the first steps went in one direction, though others would have led to adequate prosperity as well. Nevertheless, our understanding of the evolution and ecology of conifer defences has been greatly advanced by recent studies of resin defence phenotypes in relation to resource availability, population genetics and tree resistance to natural enemies under field conditions.
Continued focus on the mechanisms and patterns of pine defences across species and ecosystems is sure to yield exciting results. The authors thank Jeffry Mitton, the Editor, and reviewers for their helpful comments and suggestions.
Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide. Sign In or Create an Account. Close mobile search navigation Article navigation. Drivers of variation in conifer defence phenotypes. Future directions in the study of conifer defences.
To grow or defend? Pine seedlings grow less but induce more defences when a key resource is limited Scott Ferrenberg.
Drivers of variation in conifer defence phenotypes Moreira et al.