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571.
Terhi Vuorinen Anne-Marja Nerg Leena Syrjälä Petri Peltonen Jarmo K. Holopainen 《Arthropod-Plant Interactions》2007,1(3):159-165
The production of volatile organic compounds (VOCs) through the activation of different signal-transduction pathways may be
induced in various biotic and abiotic stress situations having importance e.g. in insect and disease resistance. We compared
the emission of VOCs emitted from silver birch Betula pendula Roth (clones 4 and 80) twigs damaged either by larvae of Epirrita autumnata, or infected with pathogenic leaf spot causing fungus Marssonina betulae. We also analysed whether local herbivore damage can systemically induce the release of VOCs from the undamaged top of same
sapling. The emissions of methylsalicylate (MeSA), (Z)-ocimene, (E)-β-ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and linalool were induced from the twigs after 72 h feeding damage by E. autumnata larvae. However, 48 h feeding damage did not induce rapid systemic release of VOCs from undamaged top leaves of the same
twigs. Pathogen-infected birch twigs had significantly greater emission of (Z)-ocimene and (E)-β-ocimene than intact control twigs. The emission of DMNT was not significantly induced and MeSA was not found at all after
pathogen infection, both being significantly different from herbivore damaged twigs. According to our results leaf fungal
pathogen induces VOC emission profile differs from that of arthropod herbivore-damaged leaves, suggesting that birch is able
to transmit parasite-specific information via VOC emissions to conspecifics and natural enemies of herbivores.
Handling editor: Yvan Rahbé 相似文献
572.
Fertilization effects on fineroot biomass, rhizosphere microbes and respiratory fluxes in hardwood forest soils 总被引:5,自引:1,他引:4
Fertilizer-induced reductions in CO(2) flux from soil ((F)CO(2)) in forests have previously been attributed to decreased carbon allocation to roots, and decreased decomposition as a result of nitrogen suppression of fungal activity. Here, we present evidence that decreased microbial respiration in the rhizosphere may also contribute to (F)CO(2) reductions in fertilized forest soils. Fertilization reduced (F)CO(2) by 16-19% in 65-yr-old plantations of northern red oak (Quercus rubra) and sugar maple (Acer saccharum), and in a natural 85-yr-old yellow birch (Betula allegheniensis) stand. In oak plots, fertilization had no effects on fine root biomass but reduced mycorrhizal colonization by 18% and microbial respiration by 43%. In maple plots, fertilization reduced root biomass, mycorrhizal colonization and microbial respiration by 22, 16 and 46%, respectively. In birch plots, fertilization reduced microbial respiration by 36%, but had variable effects on root biomass and mycorrhizal colonization. In plots of all three species, fertilization effects on microbial respiration were greater in rhizosphere than in bulk soil, possibly as a result of decreased rhizosphere carbon flux from these species in fertile soils. Because rhizosphere processes may influence nutrient availability and carbon storage in forest ecosystems, future research is needed to better quantify rhizo-microbial contributions to (F)CO(2). 相似文献
573.
The population demography of Betula maximowicziana,a cool‐temperate tree species in Japan,in relation to the last glacial period: its admixture‐like genetic structure is the result of simple population splitting not admixing 下载免费PDF全文
Conservation of the local genetic variation and evolutionary integrity of economically and ecologically important trees is a key aspect of studies involving forest genetics, and a population demographic history of the target species provides valuable information for this purpose. Here, the genetic structure of 48 populations of Betula maximowicziana was assessed using 12 expressed sequence tag–simple sequence repeat (EST‐SSR) markers. Genetic diversity was lower in northern populations than southern ones and structure analysis revealed three groups: northern and southern clusters and an admixed group. Eleven more genomic‐SSR loci were added and the demographic history of these three groups was inferred by approximate Bayesian computation (ABC). The ABC revealed that a simple split scenario was much more likely than isolation with admixture, suggesting that the admixture‐like structure detected in this species was due to ancestral polymorphisms. The ABC analysis suggested that the population growth and divergence of the three groups occurred 96 800 (95% CI, 20 500–599 000) and 28 300 (95% CI, 8700–98 400) years ago, respectively. We need to be aware of several sources of uncertainty in the inference such as assumptions about the generation time, overlapping of generations, confidence intervals of the estimated parameters and the assumed model in the ABC. However, the results of the ABC together with the model‐based maps of reconstructed past species distribution and palaeoecological data suggested that the modern genetic structure of B. maximowicziana originated prior to the last glacial maximum (LGM) and that some populations survived in the northern range even during the LGM. 相似文献
574.
575.
Background and AimsCarbon reserves are a critical source of energy and substrates that allow trees to cope with periods of minimal carbon gain and/or high carbon demands, conditions which are prevalent in high-latitude forests. However, we have a poor understanding of carbon reserve dynamics at the whole-tree level in mature boreal trees. We therefore sought to quantify the seasonal changes in whole-tree and organ-level carbon reserve pools in mature boreal Betula papyrifera.MethodsNon-structural carbohydrate (NSC; soluble sugars and starch) tissue concentrations were measured at key phenological stages throughout a calendar year in the roots, stem (inner bark and xylem), branches and leaves, and scaled up to estimate changes in organ and whole-tree NSC pool sizes. Fine root and stem growth were also measured to compare the timing of growth processes with changes in NSC pools.Key ResultsThe whole-tree NSC pool increased from its spring minimum to its maximum at bud set, producing an average seasonal fluctuation of 0.96 kg per tree. This fluctuation represents a 72 % change in the whole-tree NSC pool, which greatly exceeds the relative change reported for more temperate conspecifics. At the organ level, branches accounted for roughly 48–60 % of the whole-tree NSC pool throughout the year, and their seasonal fluctuation was four to eight times greater than that observed in the stemwood, coarse roots and inner bark.ConclusionsBranches in boreal B. papyrifera were the largest and most dynamic storage pool, suggesting that storage changes at the branch level largely drive whole-tree storage dynamics in these trees. The greater whole-tree seasonal NSC fluctuation in boreal vs. temperate B. papyrifera may result from (1) higher soluble sugar concentration requirements in branches for frost protection, and/or (2) a larger reliance on reserves to fuel new leaf and shoot growth in the spring. 相似文献
576.
红桦(Betula albo-sinensis)林是太白山森林植被的重要类型,在山地植被垂直带谱中成为落叶阔叶林带的一个亚带,南坡分布于海拔1950—2650m,北坡分布于海拔2200—2750m。 太白山红桦林可分为7个类型: Ⅰ红桦+辽东栎林,Ⅱ红桦+辽东栎+华山松林,Ⅲ红桦 +华山松林,Ⅳ红桦纯林,Ⅴ红桦+华山松+牛皮桦林,Ⅵ红桦+牛皮桦+巴山冷杉林,Ⅶ红桦 +牛皮桦林。随着海拔高度的升高,红桦林各类型依次有规律的分布,但红桦始终占据优势地位,并有着相对稳定的结构组成。红桦林以高大粗壮的红桦个体为主,林内更新苗较少,天然更新状况普遍不良。优势种群(红桦)年龄分析表明,红桦种群为衰退种群。红桦种群的衰退特征反映出红桦林的消退发展趋势。 目前本区红桦林多属成熟林或过熟林,应加强人工更新。 相似文献
577.
Flobert Ndah Hanna Valolahti Michelle Schollert Anders Michelsen Riikka Rinnan Minna Kivimenp 《Annals of botany》2022,129(4):443
Background and AimsClimate change is subjecting subarctic ecosystems to elevated temperature, increased nutrient availability and reduced light availability (due to increasing cloud cover). This may affect subarctic vegetation by altering the emissions of biogenic volatile organic compounds (BVOCs) and leaf anatomy. We investigated the effects of increased nutrient availability on BVOC emissions and leaf anatomy of three subarctic dwarf shrub species, Empetrum hermaphroditum, Cassiope tetragona and Betula nana, and if increased nutrient availability modifies the responses to warming and shading.MethodsMeasurements of BVOCs were performed in situ in long-term field experiments in the Subarctic using a dynamic enclosure system and collection of BVOCs into adsorbent cartridges analysed by gas chromatography–mass spectrometry. Leaf anatomy was studied using light microscopy and scanning electron microscopy.Key ResultsIncreased nutrient availability increased monoterpene emission rates and altered the emission profile of B. nana, and increased sesquiterpene and oxygenated monoterpene emissions of C. tetragona. Increased nutrient availability increased leaf tissue thicknesses of B. nana and C. tetragona, while it caused thinner epidermis and the highest fraction of functional (intact) glandular trichomes for E. hermaphroditum. Increased nutrient availability and warming synergistically increased mesophyll intercellular space of B. nana and glandular trichome density of C. tetragona, while treatments combining increased nutrient availability and shading had an opposite effect in C. tetragona.ConclusionsIncreased nutrient availability may enhance the protection capacity against biotic and abiotic stresses (especially heat and drought) in subarctic shrubs under future warming conditions as opposed to increased cloudiness, which could lead to decreased resistance. The study emphasizes the importance of changes in nutrient availability in the Subarctic, which can interact with climate warming and increased cloudiness effects. 相似文献
578.
Ontogenetic patterns of leaf CO2 exchange, morphology and chemistry in Betula pendula trees 总被引:3,自引:0,他引:3
J. Oleksyn R. Żytkowiak P. B. Reich M. G. Tjoelker P. Karolewski 《Trees - Structure and Function》2000,14(5):271-281
In order to explore ontogenetic variation in leaf-level physiological traits of Betula pendula trees, we measured changes in mass- (A
mass) and area-based (A
area) net photosynthesis under light-saturated conditions, mass- (RSmass) and area-based (RSarea) leaf respiration, relative growth rate, leaf mass per area (LMA), total nonstructural carbohydrates (TNC), and macro- and
micronutrient concentrations. Expanding leaves maintained high rates of A
area, but due to high growth respiration rates, net CO2 fixation occurred only at irradiances >200 μmol photons m–2 s–1. We found that full structural leaf development is not a necessary prerequisite for maintaining positive CO2 balance in young birch leaves. Maximum rates of A
area were realized in late June and early July, whereas the highest values of A
mass occurred in May and steadily declined thereafter. The maintenance respiration rate averaged ≈8 nmol CO2 g–1 s–1, whereas growth respiration varied between 0 and 65 nmol CO2 g–1 s–1. After reaching its lowest point in mid-June, leaf respiration increased gradually until the end of the growing season. Mass
and area-based dark respiration were significantly positively correlated with LMA at stages of leaf maturity, and senescence.
Concentrations of P and K decreased during leaf development and stabilized or increased during maturity, and concentrations
of immobile elements such as Ca, Mn and B increased throughout the growing season. Identification of interrelations between
leaf development, CO2 exchange, TNC and leaf nutrients allowed us to define factors related to ontogenetic variation in leaf-level physiological
traits and can be helpful in establishing periods appropriate for sampling birch leaves for diagnostic purposes such as assessment
of plant and site productivity or effects of biotic or abiotic factors.
Received: 29 December 1998 / Accepted: 26 July 1999 相似文献
579.
High- and low-altitude ecotypes of mountain birch (Betula pubescens ssp. czerepanovii) showed clear differences in their responses to various experimental conditions, including two temperature regimes and four
fertilisation rates. There was, however, no simple way to characterise the elevational ecotypes in terms of relative growth
rate, nitrogen (N) productivity, or root N uptake rate. The leaf N concentration was generally higher in the high-altitude
seedlings than in the low-altitude seedlings. At low temperature, high-altitude mountain birch maintained a relatively high
growth rate by combining high root N uptake rate and high leaf N concentration with high N productivity. An increase in temperature
and/or fertiliser rate resulted in a marginal increase in N productivity in the high-altitude seedlings but resulted in a
strong increase in N productivity in the low-altitude seedlings. In parallel, increased temperature resulted in a pronounced
decrease in leaf N concentration only in the low-altitude seedlings. Our results suggest that the weak growth response to
increased temperature in high-altitude mountain birch is functionally related to high leaf N concentration. The high leaf
N concentration of high-altitude mountain birch is genetically determined and has an adaptive value in a cold environment.
This suggests that there is a trade-off between high N productivity at low temperature and a strong response of N productivity
to temperature.
Received: 21 March 1998 / Accepted: 1 December 1998 相似文献
580.
Mast seeding in Abies balsamea, Acer saccharum and Betula alleghaniensis in an old growth, cold temperate forest of north-eastern North America 总被引:1,自引:0,他引:1
Gilles Houle 《Journal of Ecology》1999,87(3):413-422
1 Several hypotheses have been put forward to explain the phenomenon of masting or mast seeding, i.e. the supra-annual, periodic production of a large number of seeds in long-lived plants. Some of these hypotheses deal with the proximate causes of masting (e.g. the climate hypothesis) but others are concerned mostly with ultimate, evolutionary explanations (e.g. the pollination efficiency hypothesis).
2 The seed production of three tree species, Abies balsamea , Acer saccharum and Betula alleghaniensis , was followed over a 7-year period in an old-growth, cold temperate forest of north-eastern North America. The main objectives were to determine the extent of interannual variations in seed production, to investigate the relationship between viable and potential seed crop and crop efficiency, and to explore the effects of climate on seed production.
3 Potential and viable seed production varied significantly among years for all three species. However, the timing of dispersal remained the same regardless of the level of seed production.
4 Seed rain was spatially less heterogeneous in years of high seed production, suggesting that most trees were reproducing in such years.
5 Over the 7-year period, there was a significant concordance among species in their viable seed crop and crop efficiency, but not in their potential seed crop. Crop efficiency was positively correlated to potential seed crop for Abies and Betula , but not for Acer .
6 High seed production was related to warm, dry conditions in the spring of the previous year (i.e. at reproductive bud initiation) but to a moist summer in the year of seed maturation.
7 Masting in these three species thus appears to be controlled by several factors, including climate and pollination efficiency. 相似文献
2 The seed production of three tree species, Abies balsamea , Acer saccharum and Betula alleghaniensis , was followed over a 7-year period in an old-growth, cold temperate forest of north-eastern North America. The main objectives were to determine the extent of interannual variations in seed production, to investigate the relationship between viable and potential seed crop and crop efficiency, and to explore the effects of climate on seed production.
3 Potential and viable seed production varied significantly among years for all three species. However, the timing of dispersal remained the same regardless of the level of seed production.
4 Seed rain was spatially less heterogeneous in years of high seed production, suggesting that most trees were reproducing in such years.
5 Over the 7-year period, there was a significant concordance among species in their viable seed crop and crop efficiency, but not in their potential seed crop. Crop efficiency was positively correlated to potential seed crop for Abies and Betula , but not for Acer .
6 High seed production was related to warm, dry conditions in the spring of the previous year (i.e. at reproductive bud initiation) but to a moist summer in the year of seed maturation.
7 Masting in these three species thus appears to be controlled by several factors, including climate and pollination efficiency. 相似文献