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1.
To better understand the relationship between salinity and the carbon stable isotope composition (expressed as δ13C) of mangrove plants and to test whether the patterns of variation in δ13C of mangrove plants differ from those of nonhalophytes as response to salinity, the effect of salinity on leaf δ13C in two dominant mangrove species, Aegiceras corniculatum and Kandelia candel, was studied. Furthermore, to determine whether the variation in δ13C of mangrove species is adjusted by stomatal conductance, K. candel was selected as an example, and leaf gas-exchange characteristics of the seedlings were measured. It was observed that both
mangrove species had a lower leaf δ13C under their optimum salinity (1.50% for Ae. corniculatum and 2.00% for K. candel). This variation in δ13C of mangrove plants was attributable largely to stomatal adjustment as for nonhalophytes in which a strong correlation between
δ13C and relevant photosynthetic properties is observed. This result suggests that the different response pattern in δ13C was a consequence of the variation in stomata in relation to the different tolerance to salinity. The optimum salinity inferred
by leaf δ13C provides a feasible method for comparing salt tolerance between mangrove plants belonging to different species, which is
useful for mangrove restoration. 相似文献
2.
Increased use of stable isotope analysis to examine food-web dynamics, migration, transfer of nutrients, and behavior will likely result in expansion of stable isotope studies investigating human-induced global changes. Recent elevation of atmospheric CO2 concentration, related primarily to fossil fuel combustion, has reduced atmospheric CO2 δ13C (13C/12C), and this change in isotopic baseline has, in turn, reduced plant and animal tissue δ13C of terrestrial and aquatic organisms. Such depletion in CO2 δ13C and its effects on tissue δ13C may introduce bias into δ13C investigations, and if this variation is not controlled, may confound interpretation of results obtained from tissue samples collected over a temporal span. To control for this source of variation, we used a high-precision record of atmospheric CO2 δ13C from ice cores and direct atmospheric measurements to model modern change in CO2 δ13C. From this model, we estimated a correction factor that controls for atmospheric change; this correction reduces bias associated with changes in atmospheric isotopic baseline and facilitates comparison of tissue δ13C collected over multiple years. To exemplify the importance of accounting for atmospheric CO2 δ13C depletion, we applied the correction to a dataset of collagen δ13C obtained from mountain lion (Puma concolor) bone samples collected in California between 1893 and 1995. Before correction, in three of four ecoregions collagen δ13C decreased significantly concurrent with depletion of atmospheric CO2 δ13C (n ≥ 32, P ≤ 0.01). Application of the correction to collagen δ13C data removed trends from regions demonstrating significant declines, and measurement error associated with the correction did not add substantial variation to adjusted estimates. Controlling for long-term atmospheric variation and correcting tissue samples for changes in isotopic baseline facilitate analysis of samples that span a large temporal range. 相似文献
3.
This study characterized morphological and physiological responses of two Malus species to exogenous abscisic acid (ABA) application under both well-watered and drought-stressed conditions. Exogenous ABA
was sprayed onto the leaves of potted 1-year-old seedlings of M. sieversii and M. hupehensis, originated from regions with low annual rainfall and high annual rainfall, respectively. The results demonstrated that exogenous
ABA application significantly decreased height growth (H), total biomass (TB), total leaf area (LA), net photosynthesis (A) and stomatal conductance (g
s), and significantly increased root/shoot ratio (RS), specific leaf area (SLA), endogenous ABA concentration, water use efficiency
(WUE) and carbon isotope composition (δ13C) under both well-watered and drought-stressed conditions. However, distinct interspecific differences were found in ABA-induced
morphological and physiological responses. Compared with M. hupehensis, M. sieversii was more responsive to exogenous ABA application, resulting in larger decreases in H, LA, A and g
s, and larger increases in RS, SLA, WUEL, WUEi, ABA and δ13C. These results suggest strong evidence for different maintenance of fitness under stressful conditions between species of
Malus. In addition, application of exogenous ABA appears to enhance the tolerance of two Malus species to drought-stress. 相似文献
4.
Avishag Levi Andrew H. Paterson Vered Barak Dan Yakir Baohua Wang Peng W. Chee Yehoshua Saranga 《Molecular breeding : new strategies in plant improvement》2009,23(2):179-195
Quantitative trait loci (QTLs) for yield and drought related physiological traits, osmotic potential (OP), carbon isotope
ratio (δ13C, an indicator of water use efficiency), and leaf chlorophyll content (Chl), were exchanged via marker-assisted selection
(MAS) between elite cultivars of the two cotton species Gossypium barbadense cv. F-177 and G. hirsutum cv. Siv’on. The resulting near isogenic lines (NILs) were examined in two field trials, each with two irrigation regimes,
in order to (1) evaluate the potential to improve cotton drought resistance by MAS and (2) test the role of physiological
traits in plant productivity. NILs introgressed with QTLs for high yield rarely exhibited an advantage in yield relative to
the recipient parent, whereas a considerable number of NILs exhibited the expected phenotype in terms of lower OP (5 out of
9), higher δ13C (4 out of 6) or high Chl (2 out of 3). Several NILs exhibited considerable modifications in non-targeted traits including
leaf morphology, stomatal conductance and specific leaf weight (SLW). In G. barbadense genotypes, yield was correlated negatively with δ13C and OP and positively with stomatal conductance, SLW and Chl, whereas in G. hirsutum yield was negatively correlated with δ13C, SLW and Chl. This dissimilarity suggests that each of the respective species has evolved different mechanisms underlying
plant productivity. We conclude that the improvement of drought related traits in cotton NILs may lead to improved drought
resistance via MAS, but that conventional breeding may be necessary to combine the introduced QTL(s) with high yield potential. 相似文献
5.
Carbon isotopic composition of soils subjected to C3–C4 vegetation change can be used to estimate C turnover in bulk soil and in soil organic matter (SOM) pools with fast and intermediate
turnover rates. We hypothesized that the biological availability of SOM pools is inversely proportional to their thermal stability,
so that thermogravimetry can be used to separate SOM pools with contrasting turnover rates. Soil samples from a field plot
cultivated for 10.5 years with the perennial C4 plant Miscanthus×gigantheus were analyzed by thermogravimetry coupled with differential scanning calorimetry (DSC). Three SOM fractions were distinguished
according to the differential weight losses and exothermic or endothermic reactions measured by DSC. The δ13C and δ15N values of these three fractions obtained by gradual soil heating were measured by IRMS. The weight losses up to 190 °C mainly
reflected water evaporation because no significant C and N losses were detected and δ13C and δ15N values of the residual SOM remained unchanged. The δ13C values (−16.4‰) of SOM fraction decomposed between 190 and 390 °C (containing 79% of total soil C) were slightly closer
to that of the Miscanthus plant tissues (δ13C = −11.8‰) compared to the δ13C values (−16.8‰) of SOM fraction decomposed above 390 °C containing the residual 21% of SOM. Thus, the C turnover in the
thermally labile fraction was faster than that in thermally stable fractions, but the differences were not very strong. Therefore,
in this first study combining TG-DSC with isotopic analysis, we conclude that the thermal stability of SOM was not very strongly
related to biological availability of SOM fractions. In contrast to δ13C, the δ15N values strongly differed between SOM fractions, suggesting that N turnover in the soil was different from C turnover. More
detailed fractionation of SOM by thermal analysis with subsequent isotopic analysis may improve the resolution for δ13C. 相似文献
6.
Associations between δ13C values and leaf gas exchanges and tree-ring or needle growth, used in ecophysiological compositions, can be complex depending
on the relative timing of CO2 uptake and subsequent redistribution and allocation of carbon to needle and stem components. For palaeoenvironmental and
dendroecological studies it is often interpreted in terms of a simple model of δ13C fractionation in C3 plants. However, in spite of potential complicating factors, few studies have actually examined these relationships in mature
trees over inter- and intra-annual time-scales. Here, we present results from a 4 years study that investigated the links
between variations in leaf gas-exchange properties, growth, and dated δ13C values along the needles and across tree rings of Aleppo pine trees growing in a semi-arid region under natural conditions
or with supplemental summer irrigation. Sub-sections of tissue across annual rings and along needles, for which time of formation
was resolved from growth rate analyses, showed rapid growth and δ13C responses to changing environmental conditions. Seasonal cycles of growth and δ13C (up to ~4‰) significantly correlated (P<0.01) with photosynthetically active radiation, vapour pressure deficit, air temperature, and soil water content. The irrigation
significantly increased leaf net assimilation, stomatal conductance and needle and tree-ring growth rate, and markedly decreased
needle and tree-ring δ13C values and its sensitivity to environmental parameters. The δ13C estimates derived from gas-exchange parameters, and weighted by assimilation, compared closely with seasonal and inter-annual
δ13C values of needle- and tree-ring tissue. Higher stomatal conductances of the irrigated trees (0.22 vs. 0.08 mol m−2 s−1 on average) corresponded with ~2.0‰ lower average δ13C values, both measured and derived. Derived and measured δ13C values also indicated that needle growth, which occurs throughout the stressful summer was supported by carbon from concurrent,
low rate assimilation. For Aleppo pine under semi-arid and irrigated conditions, the δ13C of tree-ring and needle material proved, in general, to be a reasonable indicator of integrated leaf gas-exchange properties. 相似文献
7.
Lu-lu Song Jiang-wen Fan Warwick Harris Shao-hong Wu Hua-ping Zhong Yong-chun Zhou Ning Wang Xu-dong Zhu 《Plant Ecology》2012,213(1):89-101
Community structure and leaf traits are important elements of terrestrial ecosystems. Changes of community structure and leaf
traits are of particular use in the study of the influence of climate change on terrestrial ecosystems. Patterns of community
structure (including species richness, above- and below-ground biomass) and leaf traits (including leaf mass per area (LMA),
nitrogen content both on mass and area bases (N
mass and N
area), and foliar δ13C) from 19 grassland plots along an altitudinal transect at Hongchiba in Chongqing, China, were analyzed. Species richness
along the altitudinal transect had a hump-shaped pattern. Above-ground biomass had a quadratic decrease along the altitudinal
gradient whereas below-ground biomass had the opposite pattern. Change of above-ground biomass of various taxonomic groups
with altitude was also studied. Poaceae showed strong negative relationships and Asteraceae showed a hump-shaped relationship
with increase of altitude. Five common species of the grassland, Trifolium pratense, Geranium wilfordii,
Aster tataricus, Leontopodium leontopodioides, and Spiraea prunifolia, were particularly studied for variation of leaf traits along the altitudinal gradient. Averaged for all species, LMA, N
area and foliar δ13C had positive correlations with altitude. N
mass did not change significantly as altitude increased. LMA and N
area showed significant positive relationships with foliar δ13C. The adaptive features of leaf traits among different species were not consistent. The study highlights specific adaptation
patterns in relation to altitude for different plant species, provides further insights into adaptive trends of community
structure and leaf traits in a specific ecological region filling a gap in the definition of global patterns, and adds to
the understanding of how adaptive patterns of plants may respond to global climate change. 相似文献
8.
Victoria J. Stokes Michael D. Morecroft James I. L. Morison 《Trees - Structure and Function》2010,24(2):297-306
The seasonal trends in water use efficiency of sun and shade leaves of mature oak (Quercus robur) and sycamore (Acer pseudoplatanus) trees were assessed in the upper canopy of an English woodland. Intrinsic water use efficiency (net CO2 assimilation rate/leaf conductance, A/g) was measured by gas exchange and inferred from C isotope discrimination (δ13C) methods. Shade leaves had consistently lower δ13C than sun leaves (by 1–2‰), the difference being larger in sycamore. Buds had distinct sun and shade isotopic signatures
before bud break and received an influx of 13C-rich C before becoming net autotrophs. After leaf full expansion, δ13C declined by 1–2‰ gradually through the season, emphasising the importance of imported carbon in the interpretation of leaf
δ13C values in perennial species. There was no significant difference between the two species in the value of intrinsic water
use efficiency for either sun or shade leaves. For sun leaves, season-long A/g calculated from δ13C (72–78 μmol CO2 [mol H2O]−1) was 10–16% higher than that obtained from gas exchange and in situ estimates of leaf boundary layer conductance. For shade
leaves, the gas exchange–derived values were low, only 10–18% of the δ13C-derived values. This is ascribed to difficulties in obtaining a comprehensive sample of gas exchange measurements in the
rapidly changing light environment. 相似文献
9.
Summary Well watered plants of Vigna unguiculata (L.) Walp cv. California Blackeye No. 5 had maximum photosynthetic rates of 16 mol m-2 s-1 (at ambient CO2 concentration and environmental parameters optimal for high CO2 uptake). Leaf conductance declined with increasing water vapour concentration difference between leaf and air (w), but it increased with increasing leaf temperature at a constant small w. When light was varied, CO2 assimilation and leaf conductance were correlated linearly. We tested the hypothesis that g was controlled by photosynthesis via intercellular CO2 concentration (c
i). No unique relationship between (1) c
i, (2) the difference between ambient CO2 concentration (c
a) and c
i, namely c
a-c
i, or (3) the c
i/c
a ratio and g was found. g and A appeared to respond to environmental factors fairly independently of each other. The effects of different rates of soil drying on leaf gas exchange were studied. At unchanged air humidity, different rates of soil drying were produced by using (a) different soils, (b) different irrigation schemes and (c) different soil volumes per plant. Although the soil dried to wilting point the relative leaf water content was little affected. Different soil drying rates always resulted in the same response of photosynthetic capacity (A
max) and corresponding leaf conductance (g(Amax)) when plotted against percent relative plant-extractable soil water content (W
e
%) but the relationship with relative soil water content (W
e
) was less clear. Above a range of W
e
of 15%–25%, A
max and g(Amax) were both high and responded little to decreasing W
e
. As soon as W
e
fell below this range, A
max and g(Amax) declined. The data suggest root-to-leaf communication not mediated via relative leaf water content. However, g(Amax) was initially more affected than A
max.List of abbreviations
A CO2
assimilation
-
A
max
photosynthetic capacity at favourable ambient conditions
-
c
a CO2
concentration of the air in the leaf chamber
-
c
i
intercellular
- CO2
concentration
-
E
transpiration
-
g
leaf conductance
-
g(Amax)
leaf conductance corresponding to photosynthetic capacity
-
I
photon flux rate
-
T
l
leaf temperature
-
W
e
relative plant-extractable soil water content
-
W
e
absolute plant-extractable soil water content
-
W
l
relative leaf water content
-
W
s
relative soil water content
- w
difference in water vapour mole fraction between leaf and air
-
leaf water potential 相似文献
10.
Sheng-Gong Li Maki Tsujimura Atsuko Sugimoto Gombo Davaa Dambaravjaa Oyunbaatar Michiaki Sugita 《Trees - Structure and Function》2007,21(4):479-490
This paper reports the temporal variation (2002–2004) in foliar δ13C values, which are indicative of long-term integrated photosynthetic and water use characteristics, of Siberian larch (Larix sibirica Ledeb.) trees in a montane forest at Mongonmorit, NE Mongolia. At the stand, the δ13C value for understory shaded leaves was more negative by 2‰ on average than that for sunlit leaves sampled concurrently from
open and sun-exposed environments in a forest gap. The δ13C value of both sunlit and shaded leaves showed pronounced intra- but relatively small inter-seasonal variations. The δ13C value was more positive for juvenile than mature leaves. We conjecture that juvenile leaves may derive carbon reserves in
woody tissues (e.g., stems). Regardless of leaf habitats, the δ13C value was also affected by insect herbivores occurred in mid summer of 2003, being more negative in newly emerging leaves
from the twigs after defoliation than in non-defoliated mature leaves. This pattern seems to contrast with that for the juvenile
leaves in the early growing season. We surmise that the newly emerging leaves used stored organic carbon that was depleted
due to fractionation during remobilization and translocation for leaf regrowth. There was also intra- and inter-seasonal variation
in the foliar N concentrations and C:N ratios. A good positive (negative) correlation between the foliar δ13C values and N concentrations (C:N ratios) was also observed for both sunlit and shaded leaves, suggesting that the relationship
between water and nitrogen use is a crucial factor affecting the plant carbon–water relationship in this mid latitude forest
with a cold semiarid climate. Our isotopic data demonstrate that the larches in NE Mongolia exhibits relatively higher water
use efficiency with a distinct within-season variability. 相似文献
11.
Morphological, anatomical, biochemical and physiological traits of sun and shade leaves of adult Quercus ilex, Phillyrea latifolia and Pistacia lentiscus shrub species co-occurring in the Mediterranean maquis at Castelporziano (Latium) were studied. Fully expanded sun leaves had 47% (mean of the three species) greater leaf mass area (LMA) and 31% lower specific leaf area (SLA) than shade leaves. Palisade parenchyma thickness contributed on an average 42% to the total leaf thickness, spongy layer 43%, upper epidermal cells 5%, and upper cuticle thickness 3%. Stomatal size was greater in sun (25.5 μm) than in shade leaves (23.6 μm). Total chlorophyll content per fresh mass was 71% greater in shade than in sun leaves, and nitrogen content was the highest in sun (13.7 mg g−1) than in shade leaves (11.8 mg g−1). Difference of net photosynthetic rates (P
N) between sun and shade leaves was 97% (mean of the three species). The plasticity index (sensu Valladares et al., New Phytol 148:79–91, 2000a) was the highest for physiological leaf traits (0.86) than for morphological, anatomical and biochemical ones. Q. ilex had the highest plasticity index of morphological, anatomical and physiological leaf traits (0.37, 0.28 and 0.71, respectively) that might explain its wider ecological distribution. The higher leaf plasticity of Q. ilex might be advantageous in response to varying environmental conditions, including global change. 相似文献
12.
The natural ratio of stable carbon isotopes (δ13C) was compared to leaf structural and chemical characteristics in evergreen conifers in the north-central Rockies, United
States. We sought a general model that would explain variation in δ13C across altitudinal gradients. Because variation in δ13C is attributed to the shifts between supply and demand for carbon dioxide within the leaf, we measured structural and chemical
variables related to supply and demand. We measured stomatal density, which is related to CO2 supply to the chloroplasts, and leaf nitrogen content, which is related to CO2 demand. Leaf mass per area was measured as an intermediate between supply and demand. Models were tested on four evergreen
conifers: Pseudotsuga menziesii, Abies lasiocarpa, Picea engelmannii, and Pinus contorta, which were sampled across 1800 m of altitude. We found significant variation among species in the rate of δ13C increase with altitude, ranging from 0.91‰ km–1 for A. lasiocarpa to 2.68‰ km–1 for Pinus contorta. Leaf structure and chemistry also varied with altitude: stomatal density decreased, leaf mass per area increased, but leaf
nitrogen content (per unit area) was constant. The regressions on altitude were particularly robust in Pinus contorta. Variables were derived to describe the balance between supply and demand; these variables were stomata per gram of nitrogen
and stomata per gram of leaf mass. Both derived variables should be positively related to internal CO2 supply and thus negatively related to δ13C. As expected, both derived variables were negatively correlated with δ13C. In fact, the regression on stomatal density per gram was the best fit in the study (r
2=0.72, P<0.0001); however, the relationships were species specific. The only general relationship observed was between δ13C and LMA: δ13C (‰)=–32.972+ 0.0173×LMA (r
2=0.45, P<0.0001). We conclude that species specificity of the isotopic shift indicates that evergreen conifers demonstrate varying
degrees of functional plasticity across environmental gradients, while the observed convergence of δ13C with LMA suggests that internal resistance may be the key to understanding inter-specific isotopic variation across altitude.
Received: 1 June 1999 / Accepted: 2 November 1999 相似文献
13.
δ13C and δ15N measurements are still poorly conducted in benthic invertebrate larvae. To assess the δ13C and δ15N changes occurring after a dietary shift, experiments were conducted on veliger larvae of Crepidula fornicata fed with two cultured microalgae (Isochrysis galbana and Pavlova lutheri) of known isotopic composition, 13C-enriched and 15N-depleted compared to the initial values of the larvae. Rapid changes in larval δ13C and δ15N were observed after the dietary shift, with an increase in δ13C and a decrease in δ15N. After 19 days of feeding, isotopic equilibrium was still not reached, a period which is close to the duration of the pelagic life of the larvae. This implies that the isotopic composition measured in field-collected larvae might only partly reflect actual larval feeding but also the parental isotopic signature, especially during the early developmental stages. Isotopic measurements in marine invertebrate larvae should thus be interpreted cautiously. In planktonic food web investigations, the study of field-collected larvae of different size/developmental stage may reduce potential misinterpretations. 相似文献
14.
The effects of water deficit and re-irrigation were studied in glasshouse-grown rice plants (cvs. Cimarrón and Fonaiap 2000)
which differ in their susceptibility to water deficit. Relative water content decreased from >90 to 67–69 % and recovered
to pre-stress values within 24 h after re-irrigation. The irradiance-saturated rate of photosynthesis (P
sat), transpiration rate (E), and stomatal conductance (g
s) decreased with water deficit. E and g
s decreased similarly in both cultivars, but P
sat was more strongly inhibited in Cimarrón than in Fonaiap 2000. Water deficit increased water use efficiency (WUET) over 2-fold in Fonaiap 2000 and by 1.5-fold in Cimarrón. The ratio of intercellular to ambient CO2 concentration (C
i/C
a) decreased in Fonaiap 2000 during mild stress but increased at severe stress. Contrarily, Cimarrón did not change C
i/C
a with water deficit. After re-irrigation Fonaiap 2000 recovered P
sat to ca. 80 % of control values 24 h after re-irrigation, whereas Cimarrón recovered to 60 % of control values 48 h after re-irrigation.
E and g
s recovered to a lesser extent (50 %) than P
sat, after 48 h of re-irrigation in both cultivars. Total aboveground and green (live) biomass were unaffected by water deficit
in Fonaiap 2000 but were reduced by 21 and 40 % in Cimarrón, respectively. Dead biomass increased in stressed plants of both
cultivars but to a larger extent in Cimarrón than in Fonaiap 2000. Water deficit increased δ13C in Fonaiap 2000, whereas Cimarrón was unaffected by water deficit showing lower values than those of Fonaiap 2000. δ13C was highly and linearly correlated to the ratio C
i/C
a. WUET was also significantly correlated to δ13C. 相似文献
15.
Indications of Hydraulic Lift by Pinus halepensis and Its Effects on the Water Relations of Neighbour Shrubs 总被引:1,自引:0,他引:1
We measured the stable deuterium isotopic composition of xylem sap, the shoot predawn and midday water potentials, and the
leaf δ13C of Mediterranean shrubs Pistacia lentiscus, Globularia alypum and Rosmarinus officinalis in a south-oriented transect from a large (12 m tall) Aleppo pine tree, Pinus halepensis. We aimed to study the possibility of hydraulic lift from the deep roots of this pine tree to the shallow soil layers and
its influence on these neighbour shrubs. These same traits were also studied in several individuals of the shrub Pistacia lentiscus growing with different types of neighbours: just shrubs, a small (3 – 4 m) pine tree, and the above mentioned large pine
tree. The greater the distance from P. halepensis the plants grew, the higher xylem water δD, the lower the soil water content, and, the lower the predawn and midday water
potentials were found. These results suggest the existence of an hydraulic lift from deep roots to shallow soil in this big
tree. Further indication of this existence is provided by the improved water status of P. lentiscus (higher water potentials and δD, and lower δ13C and, therefore, lower water use efficiencies) when growing close to the big pine in comparison with the same shrub species
growing close to small pines or just surrounded by other shrubs. Moreover, all these trends occurred in the dry summer season,
but disappeared in the wet spring season.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Jordi Voltas María Regina Chambel María Aránzazu Prada Juan Pedro Ferrio 《Trees - Structure and Function》2008,22(6):759-769
The Aleppo pine (Pinus halepensis Mill.) is found in the Mediterranean under a broad range of moisture and thermal conditions. Differences in severity and
duration of water stress among native habitats may act as selective forces shaping the populations’ genetic make-up in terms
of contrasting drought strategies. We hypothesised that these strategies should translate into intraspecific variation in
carbon isotope composition (δ13C, surrogate of intrinsic water-use efficiency, WUEi) of wood holocellulose, and such variation might be linked to changes in oxygen isotope composition (δ18O, proxy of stomatal conductance) and to some climatic features at origin. Thus, we evaluated δ13C, δ18O, growth and survival for 25 Aleppo pine populations covering its geographic range and grown in two common-garden tests.
We found intraspecific variability for δ13C and growth, with high-WUEi populations (which showed 18O-enriched holocellulose) having low growth. These results suggest stomatal regulation as common control for δ13C and productivity. We also detected sizeable relationships between δ13C and climate factors related to the magnitude and timing of drought such as the ratio of summer to annual rainfall. The main
climate variable associated with δ18O was minimum temperature, but only in the coldest trial, suggesting differences in growth rhythms among sources. Overall,
slow growing populations from highly-seasonal dry areas of the western Mediterranean exhibited a conservative water-use, as
opposed to fast growing sources from the northernmost distribution range. The particular behaviour of the Mediterranean Aleppo
pine as compared with other conifers demonstrates different selective roles of climate variables in determining intraspecific
fitness. 相似文献
17.
Foliar δ<Superscript>13</Superscript>C values of nine dominant species in the Loess Plateau of China
The foliar stable carbon isotope compositions (δ13C) of nine dominant species in seven sites, Yangling, Yongshou, Tongchuan, Fuxian, Ansai, Mizhi, and Shenmu, standing from
the south to the north in the Loess Plateau of China were studied. The results showed that foliar δ13C values ranged from −22.61 to −30.73 ‰ with an average of −27.23 ‰ in 141 C3 plant samples collected from the Loess Plateau. Foliar δ13C values varied significantly (p<0.001) among the nine C3 species, which were Pinus tabulaeformis Carr., Robinia pseudoacacia L., Zizyphus jujuba Mill. var. spinosus Hu., Rubus parvifolius L., Hippophae rhamnoides L., Caragana korshinskii Kom., Lespedeza davurica (Laxm.) Schindl., Artemisia sacrorum Ledeb. var. incana Mattf., and Agropyron cristatum Gaertn. Comparatively, R. pseudoacacia, H. rhamnoides, and C. korshinskii had much higher δ13C values than the other six species, while A. sacrorum had the lowest δ13C value. There was no significant difference in foliar δ13C value among five species, P. tabulaeformis, Z. jujuba, R. parvifolius, L. davurica, and A. cristatum. Considering the life forms categorized from nine C3 species, trees and shrubs had significantly higher δ13C values than herbs (p<0.001). The deciduous tree R. pseudoacacia had much higher δ13C value than the evergreen tree P. tabulaeformis (p<0.01). Among the four shrubs, foliar δ13C values in H. rhamnoides and C. korshinskii were markedly higher (p<0.01) than those in Z. jujuba and R. parvifolius. Among the three herbs, L. davurica and A. cristatum had significantly higher δ13C values than A. sacrorum (p<0.01). Leguminous species such as R. pseudoacacia, C. korshinskii, and L. davurica as well as a non-leguminous species with nitrogen-fixation capacity, H. rhamnoides, had higher δ13C values than other non-leguminous species with same life-form. The mean δ13C value increased by about 7 % from Yangling in the south to Shenmu in the north as climatic drought increased, and foliar
δ13C values differed much (p<0.001) among the seven sites. For nine species in the Loess Plateau, foliar δ13C values were significantly and negatively (p<0.001) correlated with the mean annual precipitation, moreover, an increase of 100 mm in annual precipitation would result
in a decrease of 1.2 ‰ in δ13C value. 相似文献
18.
Voigt CC Grasse P Rex K Hetz SK Speakman JR 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2008,178(1):9-16
We analysed the stable carbon isotope ratio in exhaled CO2 (δ13Cbreath) of free-ranging vampires to assess the type of metabolized substrate (endogenous or exogenous substrate) and its origin,
i.e. whether the carbon atoms came from a C4 food web (grass and cattle) or the C3 food web in which they were captured (a rainforest remnant and its mammals). For an improved understanding of factors influencing
the δ13Cbreath of vampires, we conducted feeding experiments with captive animals. The mean δ13Cbreath of starved bats was depleted in 13C in relation to the diet by 4.6‰ (n = 10). Once fed with blood, δ13Cbreath levelled off within a short time approximately 2.2‰ above the stable carbon isotope signature of the diet. The median time
required to exchange 50% of the carbon atoms in exhaled CO2 with carbon atoms from the ingested blood was 18.6 min (mean 29.5 ± 19.0 min, n = 5). The average δ13C of wing membrane and fur in free-ranging vampire bats suggested that bats almost exclusively foraged for cattle blood during
the past weeks. The δ13Cbreath of the same bats averaged −19.1‰. Given that all free-ranging vampires were starving and that the δ13C of cattle was more in enriched in 13C by 5–6‰ than the δ13Cbreath of vampires, we conclude that the vampire bats of our study metabolised fat that was predominantly built from carbon atoms
originating from cattle blood. Since δ13C of wing membrane and fur integrates over weeks and months respectively and δ13Cbreath over hours and days, we also conclude that vampire bats of the studied population consistently ignored rainforest mammals
and chose cattle as their prey during and prior to our study. 相似文献
19.
Carbon isotopes and water use efficiency: sense and sensitivity 总被引:1,自引:0,他引:1
We revisit the relationship between plant water use efficiency and carbon isotope signatures (δ13C) of plant material. Based on the definitions of intrinsic, instantaneous and integrated water use efficiency, we discuss
the implications for interpreting δ13C data from leaf to landscape levels, and across diurnal to decadal timescales. Previous studies have often applied a simplified,
linear relationship between δ13C, ratios of intercellular to ambient CO2 mole fraction (C
i/C
a), and water use efficiency. In contrast, photosynthetic 13C discrimination (Δ) is sensitive to the ratio of the chloroplast to ambient CO2 mole fraction, C
c/C
a (rather than C
i/C
a) and, consequently, to mesophyll conductance. Because mesophyll conductance may differ between species and over time, it
is not possible to determine C
c/C
a from the same gas exchange measurements as C
i/C
a. On the other hand, water use efficiency at the leaf level depends on evaporative demand, which does not directly affect
Δ. Water use efficiency and Δ can thus vary independently, making it difficult to obtain trends in water use efficiency from
δ13C data. As an alternative approach, we offer a model available at to explore how water use efficiency and 13C discrimination are related across leaf and canopy scales. The model provides a tool to investigate whether trends in Δ indicate
changes in leaf functional traits and/or environmental conditions during leaf growth, and how they are associated with trends
in plant water use efficiency. The model can be used, for example, to examine whether trends in δ13C signatures obtained from tree rings imply changes in tree water use efficiency in response to atmospheric CO2 increase. This is crucial for predicting how plants may respond to future climate change.
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20.
Family Chenopodiaceae is an intriguing lineage, having the largest number of C4 species among dicots, including a number of anatomical variants of Kranz anatomy and three single-cell C4 functioning species. In some previous studies, during the culture of Bienertia cycloptera Bunge ex Boiss., carbon isotope values (δ13C values) of leaves deviated from C4 to C3−C4 intermediate type, raising questions as to its mode of photosynthesis during growth in natural environments. This species
usually co-occurs with several Kranz type C4 annuals. The development of B. cycloptera morphologically and δ13C values derived from plant samples (cotyledons, leaves, bracts, shoots) were analyzed over a complete growing season in a
salt flat in north central Iran, along with eight Kranz type C4 species and one C3 species. For a number of species, plants were greenhouse-grown from seeds collected from the site, in order to examine leaf
anatomy and C4 biochemical subtype. Among the nine C4 species, the cotyledons of B. cycloptera, and of the Suaeda spp. have the same respective forms of C4 anatomy occurring in leaves, while cotyledons of members of tribe Caroxyloneae lack Kranz anatomy, which is reflected in
the δ13C values found in plants grown in the natural habitat. The nine C4 species had average seasonal δ13C values of −13.9‰ (with a range between species from −11.3 to −15.9‰). The measurements of δ13C values over a complete growing season show that B. cycloptera performs C4 photosynthesis during its life cycle in nature, similar to Kranz type species, with a seasonal average δ13C value of −15.2‰.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献