Foliar Carbon Isotope Discrimination Research Articles

Spatial variability in foliar carbon and nitrogen isotope values on Tenerife reflects both climate and soils: Establishing a framework for future work

Tenerife Island is well-known for its biodiversity. It boasts the highest elevation in the Atlantic Ocean and its northern and southern slopes have varying moisture and temperature gradients. Consequently, there are multiple spatially discrete vegetation zones, or biomes, recognized on the island that roughly follow elevation. We investigated the extent to which climatic variables as well as soil nitrogen isotope values (δ15N) and weight %N influence spatial isotopic variability in C3 plants during the rainy season and assessed the degree to which foliar carbon isotope discrimination (Δleaf) and δ15N values are able to distinguish biomes. Mean Annual Precipitation explained 71% and 55% of the spatial variability in Δleaf and δ15N values, respectively. Overall, foliar δ15N values tracked those in soils, and soil %N was negatively correlated with both soil and foliar δ15N values. However, there was considerable variability among co-occurring species, as well as among sites within the same biome, which obscured trends among biomes. As a result, only a few biomes were isotopically distinct: Broad-leaved evergreen forest and sub-desert coastal scrub on the northern slope, and summit scrub and sub-desert coastal scrub on the southern slope. Further investigation into the influence of coastal orientation, topography, plant physiology, soil characteristics, as well as seasonal and inter-annual climate variability on foliar isotope values would be fruitful. Nevertheless, these results provide baseline information for researchers seeking to interpret diet and mobility of animals and people, as well as environmental changes over time on Tenerife and other Macaronesian volcanic islands.

A Negative Relationship between Foliar Carbon Isotope Composition and Mass-Based Nitrogen Concentration on the Eastern Slope of Mount Gongga, China.

Plants adopt ecological strategy to resist environmental changes and increase their resource-use efficiency. The ecological strategy includes changes in physiological traits and leaf morphology, which may result in simultaneous variations in foliar N concentration and the ratio of intercellular CO2 concentration to ambient CO2 concentration (ci/ca). This in turn links to foliar carbon isotope discrimination, and thus, a relationship between foliar N concentration and foliar carbon isotope composition (δ13C) is expected. To understand how plants integrate their structural and physiological resistance to environmental changes, the relationship between foliar N concentration and foliarδ13C has been assessed intensively, especially the correlation between area-based N concentration (Narea) and δ13C.Less effort has been dedicated to the examination of the relationship between mass-based N concentration(Nmass) and δ13C. Studies on the Nmass–δ13C relationship, especially those including a large amount of data and species, will enhance our understanding of leaf economics and benefit ecological modeling. The present study includes an intensive investigation into this relationship by measuring foliar Nmass and δ13C in a large number of plant species grown on the eastern slope of Mount Gongga, China. This study shows that foliar Nmass decreases with increasing δ13C, which is independent of functional group, vegetation type, and altitude. This suggests that a negative correlation between Nmass and δ13C may be a general pattern for plants grown not only on Mount Gongga, but also in other areas.

Foliar carbon isotope discrimination and related traits along light gradients in two different functional-type tree species

To understand how different plant functional types respond to light intensities, foliar carbon isotope discrimination (Δ13C) and related traits, i.e., specific leaf area (SLA), mass- and area-based nitrogen concentrations (Nmass and Narea), leaf dry mass content (LDMC) of two evergreen coniferous and three deciduous broad-leaved species, were measured under four light intensities. Foliar Δ13C and SLA increased significantly from full- to low-light conditions for all species. These indicate that species studied could increase their light capture capacity under low-light conditions, leading to lower water-use efficiency (higher 13C discrimination). There were significant differences in the responses of foliar Nmass or Narea to light variations in the two functional types, indicating that different functional-type tree species may have different N-use strategies to adapt to the light variations. It was found that there were large functional-type-dependent differences with regard to the relationships between foliar Δ13C and other leaf traits. Our findings suggest that all tree species could change foliar morphology to increase their light-harvesting ability under low-light conditions at the expense of decreasing their water-use efficiency. However, large differences in N-use strategy may exist between deciduous and evergreen species, which may be vital for the survival of these two functional-type tree species in a shaded understory. More important, our findings reveal that changes in Δ13C are not directly related to foliar N if N investment does not proportionally increase the photosynthetic capacity; this should be considered when exploring the relationships of nitrogen concentrations with Δ13C.

巴郎山异型柳叶片功能性状及性状间关系对海拔的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 巴郎山异型柳叶片功能性状及性状间关系对海拔的响应 DOI: 10.5846/stxb201202020136 作者: 作者单位: 四川省林业科学研究院,中国林科院森环森保所,中国林科院森环森保所,中国林科院森环森保所,中国林科院森环森保所,四川省林业科学研究院,四川省林业科学研究院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金面上项目(30771718);中国林科院中级公益性科研院所基本科研业务费专项资金项目(CAFRIF200717); 林业公益性行业科研专项(200804001)资助 Response of leaf functional traits and the relationships among them to altitude of Salix dissa in Balang Mountain Author: Affiliation: Sichuan Academy of Forestry,,Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在卧龙自然保护区,按海拔梯度选择了4个异型柳分布地点(2350 m、2700 m、3150 m和3530 m),对各研究地点异型柳进行了叶片光合、CO2扩散导度(气孔导度(gs)和叶肉细胞导度(gm))、δ13C、氮素以及比叶面积(SLA)等参数的测量,以期揭示该植物叶片功能性状及功能性状间关系的海拔响应情况.结果表明:随着海拔的升高,大气温度和压强的降低,异型柳的叶片单位面积氮含量(Narea)、最大羧化速率(Vcmax)和最大净光合速率(Amax)均随之增加,这可能是该落叶灌木对于生长季节缩短的一种响应;同时,植物的光合氮利用效率(PNUE)和SLA却均随海拔降低,原因可能在于随着海拔的升高,植物将越来越多的氮素用于细胞壁等非光合组织的构建,这是高海拔植物对于外界恶劣环境的一种适应;最后,扩散导度和羧化能力是植物叶片δ13C的主要影响因子,而羧化能力较扩散导度对于异型柳叶片δ13C的作用更大些,进而导致该值呈现随海拔升高的趋势.氮素在光合与非光合系统间的分配是巴郎山异型柳适应不同海拔生境的关键. Abstract:The relationship between plant and environment is always one of key issues in the field of ecology. Attentions have been paid to plant functional traits and the responses of some traits to environment have been found since 19th century. Many researches at different scales have proved that plant functional trait, especially leaf functional trait, is a useful tool for linking plant and environment. However, the relationships among plant functional traits are more stable and more meaningful than the relationships among the traits and environment. Study on the responses of plant leaf functional traits and the relationships among them to altitude gradients is helpful to know how plants responding and adapting a changing environment. Foliar traits on photosynthesis, diffusional conductance to CO2 (including stomatal conductance (gs) and mesophyll conductance (gm)), carbon isotope ratio (δ 13C), nutrient content and morphology of Salix dissa shrub in four sites with different altitudes (2350m, 2700m, 3150m and 3530m) from Balang Mountain were measured and analyzed in order to understand how leaf functional traits and the relationships among them of the species responded to altitudinal gradients. The results showed that leaf nitrogen content per area (Narea), maximum rate of carboxylation (Vcmax) and maximum photosynthetic rate (Amax) increased with decrease of air temperature and air pressure along with altitude increasing. It was likely the response of the deciduous shrub to shorter growing season at higher altitude. However, photosynthetic nitrogen use efficiency (PNUE) and specific leaf area (SLA) decreased with altitude probably because S. dissa allocated more and more nitrogen to non-photosynthetic system, such as cell wall and so on as a kind of adaptation of plants to severe environment. Diffusion conductance (gs and gm) and carboxylation capacity were main factors on foliar carbon isotope discrimination, but Vcmax had more important effect on leaf δ 13C than diffusion conductance did. It resulted in leaf δ 13C of S. dissa increasing with altitude. It was obvious that allocation of nitrogen between photosynthetic system and non-photosynthetic system was a key factor on the adaptation of S. dissa to a changing environment at different altitude Balang Mountain. 参考文献 相似文献 引证文献

Correlations of carbon isotope discrimination with element and ash contents in two Sabina evergreen trees in northwest China: patterns and implications

Foliar carbon isotope discrimination (Δ) is widely used as an integrator of physiological plant responses to environmental change. However, the relationship between foliar Δ and mineral nutrient accumulation is still not well-known. The foliar Δ, K, Ca, Mg, Si and ash contents of S. przewalskii Kom. (SP) and S. chinensis (Lin.) Ant. (SC), two over-winter trees distributed on high altitude plateaux and lower altitude plains, respectively, were measured at monthly intervals over two years under the same growing conditions to examine the genetic and seasonal variation in foliar nutrient concentrations in relation to foliar Δ. The foliar Δ, Mg, K and ash contents were markedly lower in SP than in SC, and the foliar Si content was significantly higher in SP than SC, while the differences in Ca contents between the two Sabina trees were not significant. There was higher foliar Δ in winter than in summer for both Sabina trees. Close negative correlations of foliar Δ with K and Mg content, and significant positive correlations between foliar Δ and Si contents, were observed in SP but not in SC. Thus, higher water-use efficiency of SP than of SC is related to higher Si and lower Mg and K contents that have positive effects on the reduction of transpiration rates or stomatal conductances. The results obtained by the present study will advance the understanding of the adaptive strategies of mineral nutrition and water use in harsh environments.

Relationships between foliar carbon isotope discrimination with potassium concentration and ash content of the riparian plants in the extreme arid region of China

Carbon isotope discrimination (Δ) has been proposed as an indirect estimation criterion for water use efficiency in C3 plants. Because of the higher cost for Δ analysis, ash content or K concentration has been proposed as an alternative criterion for Δ in many species. In five typical habitats of the extreme arid Ejina desert oasis in northwest of China, the seasonal variations of foliar δ, ash content, and potassium (K) concentration were researched in two constructive desert riparian plants (Populus euphratica Olivier, Tamarix ramosissima Ledeb). The correlations of foliar Δ with ash content and K concentration in both species were also examined to evaluate the feasibility of the foliar ash content and K concentration as surrogates of Δ in P. euphratica and T. ramosissima. Results showed that there were significant effects of plant species, habitats and growth season on foliar Δ, ash content, and K concentration. Foliar Δ and K concentration in P. euphratica were significantly higher than those in T. ramosissima, whereas, the ash content was reverse. Among habitats, the trends of δ signatures in both P. euphratica and T. ramosissima were similar, δ values and ash content in both species were the lowest in the dune. Both in the Gobi and dune sites, K concentration in P. euphratica and T. ramosissima was different. In the whole growth period, foliar Δ values and ash content in both species were gradually increased, but K concentration was decreased. Ash content was significantly and positively related to δ in both P. euphratica and T. ramosissima. However, significantly negative correlations between foliar δ and K concentration as well as between ash content and K in P. euphratica were found. In T. ramosissima, the relationship was positive but very weak.

Relationships Between Carbon Isotope Discrimination and Yield of Spring Wheat Under Different Water and Nitrogen Levels

ABSTRACT A greenhouse experiment was conducted to investigate the relationships between foliar carbon isotope discrimination (Δ) and above ground dry matter (ADM) at different stages during a plant's life cycle, and grain carbon isotope discrimination and grain yield (GY) at maturity of spring wheat (Triticum aestivum L.) under different nitrogen (N) and water levels. Results showed that ADM and GY both increased significantly with decreasing water stress, while the effects of nitrogen on ADM and GY varied with the water conditions. Foliar and grain carbon isotope discrimination decreased with increasing water stress and increasing nitrogen levels. For all water conditions, relationships between carbon isotope discrimination (foliar and grain) and yields (ADM and GY) were significantly positive (P < 0.001) at various growth stages. However, at the same water level, the correlations were complex, and under well-watered conditions, ADM and GY were strongly and negatively correlated with foliar and grain carbon isotope discrimination at all growth stages (P < 0.001). The correlations were inconsistent and not significant at moderate water level, but were positive under drought. Our results showed that water and nitrogen both significantly affected the relationships between yield and carbon isotope discrimination of spring wheat, that there are interactions between these two parameters, and that environmental conditions such as water and fertilizer must thus be considered in future research on the relationship between yield and carbon isotope discrimination of spring wheat.

Correlations of foliar Δ with K concentration and ash content in sand-fixing plants in the Tengger Desert of China: patterns and implications

In different-aged sand-fixing zones and shifting sand dunes, the seasonal variations of foliar carbon isotope discrimination (Δ), potassium (K) concentration and ash content were investigated in three dominated deserted plants (Artemisia ordosica, Hedysarum scoparium and Caragana korshinskii) during growth season in Shapotou, which is in the southeast margin of the Tengger Desert. The correlations of foliar Δ with foliar K concentration and ash content were examined to evaluate the foliar K and ash content as surrogates of Δ in those deserted plants. Results showed that there were significant effects of plant species, micro-habitation and growth season on foliar Δ, K concentration and ash content. Foliar Δ of C. korshinskii was significantly lower than those of A. ordosica and H. scoparium, and K concentrations in A. ordosica were 2.14 and 2.36 times those of C. korshinskii and H. scoparium. At the same time, micro-habitation and the conditions in growth seasons had significant effects on foliar Δ, K concentration and ash content. Ash content and K concentration were positively correlated to Δ in A. ordosica and H. scoparium, while there was significantly negative relationship between foliar K concentration and Δ in C. korshinskii. Thus, those findings suggest that foliar ash content and K concentration can serve as surrogates of carbon isotope discrimination (Δ) in A. ordosica and H. scoparium, while they do not in C. korshinskii. This result implied that the correlations of foliar Δ with ash content and K concentration were various due to the physiological features of plant species, and species differences should be fully considered when evaluating the surrogates of carbon isotope discrimination in plants.

Variations of foliar carbon isotope discrimination and nutrient concentrations in Artemisia ordosica and Caragana korshinskii at the southeastern margin of China’s Tengger Desert

Seasonal variations in foliar stable carbon isotope discrimination (Δ) of Artemisia ordosica and Caragana korshinskii and correlations of foliar Δ with N, P, and K concentrations were studied under different planting regimes at the southeastern margin of China’s Tengger Desert. Foliar Δ, N, P, and K concentrations and the correlations of Δ with N, P, and K differed between the species and planting regimes. Foliar Δ, P and K concentrations in A. ordosica were markedly higher than in C. korshinskii, while foliar N concentrations in C. korshinskii was significantly higher than in A. ordosica. There were no significant differences in N, P, and K concentrations in C. korshinskii between planting regimes, but foliar Δ was significantly increased after June in mixed-species planting. In A. ordosica foliar N concentrations in mixed-species planting and foliar Δ in single-species planting were significantly higher than those of corresponding planting regimes. According to water-use efficiency (WUE) calculated based on foliar Δ, and on N, P, and K concentrations, C. korshinskii’s survival may profit from its higher WUE, whereas A. ordosica can avoid drought damage by its higher P and K concentrations in leaves in arid or semi-arid environments. The complex correlations of foliar Δ with foliar N, P and K suggested that water in C. korshinskii and water and P nutrition in A. ordosica were the key factors limiting their growth.

Variations in life‐form composition and foliar carbon isotope discrimination among eight plant communities under different soil moisture conditions in the Xilin River Basin, Inner Mongolia, China

AbstractWater is one of the key limiting factors for the survival and growth of plant species in arid and semi‐arid steppe regions. Different plant functional groups (PFGs) based on life‐forms differ in their strategies to cope with limited water availability. The foliar carbon isotope discrimination (Δ) value provides an integrated measurement of internal plant physiological and external environmental properties affecting photosynthetic gas exchange over the time interval when the carbon was fixed. In this study, we surveyed the composition and Δ values of various life‐forms (shrubs, sub‐shrubs, perennial grasses, perennial forbs and annuals) in eight different plant communities along a soil moisture gradient in the Xilin River Basin, Inner Mongolia, China. Our results showed that: (1) life‐forms occurred variously in eight steppe communities with different soil moisture status; (2) in wetter habitats, forbs were more abundant and accounted for the majority of aboveground biomass, whereas grasses became more important in drier habitats. Shrubs and sub‐shrubs increased with decreasing soil water availability and their relative biomass rapidly increased in degraded steppe and sand dune communities. (3) The numerical order of the mean Δ values of life‐forms is as follows: perennial grasses (15.86‰) &lt; shrubs (16.10‰) &lt; perennial forbs (16.45‰)=annuals (16.41‰) &lt; sub‐shrubs (17.55‰), reflecting their differences in water use efficiencies. The significant differences in the Δ values among these life‐forms suggested that life‐form‐based PFGs not only represent a morphological classification of these plants, but could also represent a functional group integrating different physiological processes such as water use strategies, which may partially explain the differences in PFG composition and competitive ability of co‐existing species along environmental gradients in the Xilin River Basin.

Use of decreasing foliar carbon isotope discrimination during water limitation as a carbon tracer to study whole plant carbon allocation

AbstractFoliar carbon isotope discrimination (Δ) of C3 plants decreases in water‐deficit situations as discrimination by the photosynthetic primary carboxylation reaction decreases. This diminished Δ in leaves under water deficit can be used as a tracer to study whole plant carbon allocation patterns. Carbon isotope composition (δ13C value) of leaf hot water extracts or leaf tissue sap represents a short‐term integral of leaf carbon isotope discrimination and thus represents the δ13C value of source carbon that may be distributed within a plant in water‐deficit situations. By plotting the δ13C values of source carbon against the δ13C values of sink tissues, such as roots or stems, it is possible to assess carbon allocation to and incorporation into sink organs in relation to already present biomass. This natural abundance labelling method has been tested in three independent experiments, a one‐year field study with the fruit tree species Ziziphus mauritiana and peach (Prunus persica), a medium‐term drought stress experiment with Ziziphus rotundifolia trees in the glasshouse, and a short‐term drought stress experiment with soybean (Glycine max). The data show that the natural abundance labelling method can be applied to qualitatively assess carbon allocation in drought‐stressed plants. Although it is not possible to estimate exact fluxes of assimilated carbon during water deficit the method represents an easy to use tool to study integrated plant adaptations to drought stress. In addition, it is a less laborious method that can be applied in field studies as well as in controlled experiments, with plants from any developmental stage.

Carbon isotope discrimination and oxygen isotope composition in clones of the F(1) hybrid between slash pine and Caribbean pine in relation to tree growth, water-use efficiency and foliar nutrient concentration.

The objectives of this study were: (1) to examine how foliar carbon isotope discrimination (Delta) and oxygen isotope composition (delta(18)O) are related to tree growth, ash mineral nutrient concentration and foliar nutrient concentration in 7-year-old clones of the F(1) hybrid between slash pine (Pinus elliottii Engelm.) and Caribbean pine (P. caribaea var. hondurensis Barr. et Golf.) in subtropical Australia; and (2) to evaluate the potential of using foliar Delta, ash mineral nutrient concentration and delta(18)O measurements for selecting F(1) hybrid pine clones with high water-use efficiency (WUE) and growth potential. There were significant differences in tree growth, foliar Delta, delta(18)O and ash mineral nutrient concentration among the eight clones tested. Significant negative linear relationships existed between tree growth and Delta, extrapolating to zero growth at Delta = 24-30 per thousand. There were strong genetic correlations (r = -0.83 to -0.96) between Delta and tree growth, particularly tree height. Significant non-genetic correlations (r = -0.62 to -0.80) existed between Delta and foliar K concentration. Foliar delta(18)O, ash mineral nutrient concentration and foliar nutrient concentration were unrelated to tree growth. In the F(1) hybrid pine clones, variation in tree WUE, as reflected by Delta, was largely attributed to a genetic effect on leaf photosynthetic capacity rather than on stomatal conductance, as reflected by foliar delta(18)O.

Foliar carbon isotope discrimination in Larix species and sympatric evergreen conifers: a global comparison.

Larches (Larix spp.), deciduous conifers, occur in the northern hemisphere in cold-temperate and boreal climates - an environment normally thought to favor evergreen tree species. We compare foliar carbon isotope discrimination (Δ), instantaneous water use efficiency, total foliar nitrogen concentration, and specific leaf area (for a subset of sites) between Larix spp. and co-occurring evergreen conifers at 20 sites throughout the natural range of larches. Except for Larix occidentalis in the xeric Intermountain West, USA, Δ is significantly (P < 0.05) greater for larches than co-occurring evergreen conifers at 77% of the sites, suggesting that larches use water less efficiently. At elevations greater than 3000 m, the Δ of Larix spp. and co-occurring conifers converge, suggesting that water is not the limiting resource. Foliar nitrogen concentration and specific leaf area are two ecophysiological characteristics that are positively correlated with high photosynthetic capacity. Foliar nitrogen concentration is significantly greater for larches than evergreen conifers at 88% of the sites and specific leaf area is approximately three times greater for larches than co-occurring conifers. Future studies should examine the potential effect that global warming may have on the distribution of larch forests because the water use efficiency of larches is commonly less than co-occurring evergreen conifers and the boreal and high-latitude environments are likely to experience the greatest climate warming.

Monosoonal precipitation responses of shrubs in a cold desert community on the Colorado Plateau.

South-eastern Utah forms a northern border for the region currently influenced by the Arizona monosoonal system, which feeds moisture and summer precipitation into western North America. One major consequence predicted by global climate change scenarios is an intensification of monosoonal (summer) precipitation in the aridland areas of the western United States. We examined the capacity of dominant perennial shrubs in a Colorado Plateau cold desert ecosystem of southern Utah, United States, to use summer moisture inputs. We simulated increases of 25 and 50 mm summer rain events on Atriplex canescens, Artemisia filifolia, Chrysothamnus nauseosus, Coleogyne ramosissima, and Vanclevea stylosa, in July and September with an isotopically enriched water (enriched in deuterium but not 18O). The uptake of this artificial water source was estimated by analyzing hydrogen and oxygen isotope ratios of stem water. The predawn and midday xylem water potentials and foliar carbon isotope discrimination were measured to estimate changes in water status and water-use efficiency. At. canescens and Ch. nauseosus showed little if any uptake of summer rains in either July or September. The predawn and midday xylem water potentials for control and treatment plants of these two species were not significantly different from each other. For A. filifolia and V. stylosa, up to 50% of xylem water was from the simulated summer rain, but the predawn and midday xylem water potentials were not significantly affected by the additional summer moisture input. In contrast, C. ramosissima showed significant uptake of the simulated summer rain (>50% of xylem water was from the artificial summer rain) and an increase in both predawn and midday water potentials. The percent uptake of simulated summer rain was greater when those rains were applied in September than in July, implying that high soil temperature in midsummer may in some way inhibit water uptake. Foliar carbon isotope discrimination increased significantly in the three shrubs taking up simulated summer rain, but pre-treatment differences in the absolute discrimination values were maintained among species. The ecological implications of our results are discussed in terms of the dynamics of this desert community in response to changes in the frequency and dependability of summer rains that might be associated with a northward shift in the Arizona monsoon boundary.