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1.
Carbon isotope discrimination indicates improving water-use efficiency of trees in northern Eurasia over the last 100 years 总被引:5,自引:0,他引:5
Matthias Saurer Rolf T. W. Siegwolf Fritz H. Schweingruber† 《Global Change Biology》2004,10(12):2109-2120
We investigated the response of conifer trees in northern Eurasia to climate change and increasing CO2 over the last century by measuring the carbon isotope ratio in tree rings. Samples from Larix, Pinus and Picea trees growing at 26 high‐latitude sites (59–71°N) from Norway to Eastern Siberia were analysed. When comparing the periods 1861–1890 and 1961–1990, the isotope discrimination and the ratio of the intercellular to ambient CO2 concentration (ci/ca) remained constant for trees growing in mild oceanic climate and under extremely cold and dry continental conditions. This shows a strong coordination of gas‐exchange processes, consisting in a biochemical acclimation and a reduction of the stomatal conductance. The correlation for ci/ca between the two investigated periods was particularly strong for Larix (r2=0.90) and Pinus (r2=0.94), but less pronounced for Picea (r2=0.47). Constant ci/ca under increasing CO2 in the atmosphere resulted in improved intrinsic water‐use efficiency (Wi), the amount of water loss at the leaf level per unit carbon gain. We found that 125 out of 126 trees showed increasing Wi from 1861 to 1890 to 1961 to 1990, with an average improvement of 19.2±0.9% (mean±SE). The adaptation in gas exchange and reduced transpiration of trees growing in this region must have had a strong impact on the water and energy budget, resulting in a drier and warmer surface air layer today than would exist without this vegetation–climate feedback. 相似文献
2.
R. C. NAGESWARA RAO J. H. WILLIAMS K. D. R. WADIA K. T. HUBICK G. D. FARQUHAR 《The Annals of applied biology》1993,122(2):357-367
Ten groundnut genotypes were grown under adequately irrigated conditions or subjected to drought during the pod filling phase (83–113 days after sowing) in a medium deep Alfisol at the ICRISAT Centre during the 1986–1987 post-rainy season. Crop growth was measured in both treatments, but transpiration (7) and water-use efficiency (W) were quantified only in the drought treatment. Leaf samples from both treatments were assayed for discrimination against 13CO2 fixed in leaves (Δ) to examine the relationships between Δ, crop growth, and W under field conditions. The shoot dry matter accumulated during the period of drought (Y) ranged from 72–150 g m-2 and was closely related to transpiration. This indicates scope for selection of traits and practices to increase T. Water-use efficiencies ranged from 1.38–2.50 g kg-1 and were inversely related to Δ in eight out of the 10 genotypes. For the other two genotypes, there was evidence that T was underestimated by field measurements. Water-use efficiency and transpiration were not correlated suggesting that these two traits might be combined through breeding. Variation between genotypes was greatest for the partitioning of total dry matter to pods (73%), followed by water-use efficiency (31%) and transpiration (29%). Crop growth rates were negatively related to Δ under irrigated conditions but not under drought. 相似文献
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Monclus R Dreyer E Delmotte FM Villar M Delay D Boudouresque E Petit JM Marron N Bréchet C Brignolas F 《The New phytologist》2005,167(1):53-62
Here we tested whether some leaf traits could be used as predictors for productivity in a range of Populus deltoides x P. nigra clones. These traits were assessed in 3-yr-old rooted cuttings from 29 clones growing in an open field trial, in a five randomized complete block design, under optimal irrigation. Variables were assigned to four groups describing productivity (above-ground biomass, total leaf area), leaf growth (total number of leaves increment rate), leaf structure (area of the largest leaf, specific leaf area, carbon and nitrogen contents), and carbon isotope discrimination in the leaves (Delta). High-yielding clones displayed larger total leaf area and individual leaf area, while no correlation could be detected between productivity and either leaf structure or Delta. By contrast, Delta was negatively correlated with number of leaves increment rate and leaf N content. Our study shows that there is a potential to improve water-use efficiency in poplar without necessarily reducing the overall productivity. 相似文献
6.
Beech (Fagus sylvatica L.) and pedunculate oak (Quercus robur L.) were grown from seed for two whole seasons at two CO2 concentrations (ambient and ambient + 250 μmol mol?1) with two levels of soil nutrient supply. Measurements of net leaf photosynthetic rate (A) and stomatal conductance (gs) of well-watered plants were taken over both seasons; a drought treatment was applied in the middle of the second growing season to a separate sample of beech drawn from the same population. The net leaf photosynthetic rate of well-watered plants was stimulated in elevated CO2 by an average of 75% in beech and 33% in oak; the effect continued through both growing seasons at both nutrient levels. There were no interactive effects of CO2 concentration and nutrient level on A or gs in beech or oak. Stomatal conductance was reduced in elevated CO2 by an average of 34% in oak, but in beech there were no significant reductions in gs except under cloudy conditions (–22% in elevated CO2). During drought, there was no effect of CO2 concentration on gs in beech grown with high nutrients, but for beech grown with low nutrients, gs was significantly higher in elevated CO2, causing more rapid soil drying. With high nutrient supply, soil drying was more rapid at elevated CO2 due to increased leaf area. It appears that beech may substantially increase whole-plant water consumption in elevated CO2, especially under conditions of high temperature and irradiance when damage due to high evaporative demand is most likely to occur, thereby putting itself at risk during periods of drought. 相似文献
7.
Genotypic and environmental (soil water regime and N level) variation in carbon isotope discrimination (CID) in relation to
the gas exchange, transpiration efficiency (A/T), and biomass production were investigated in field experiments using eleven rice (Oryza sativa L.) genotypes. The results showed that genotype was more dominant for variation in CID than in total biomass. Genotypic ranking
in CID was consistent across environments because of small genotype × environment interactions. Japonica genotypes tended
to have lower CID than indica genotypes. Higher soil water and lower N rate significantly increased CID. Variation in CID
was slightly smaller for water regime than for genotype. There was a negative correlation between CID andA/T among genotypes within water regimes. Genotypic variation in CID was associated mainly with variation in stomatal conductance
under all soil water regimes and with photosynthetic capacity in late growth stages under aerobic soil conditions. The decrease
in CID at higher N was probably due to lower stomatal conductance under aerobic soil conditions and to higher photosynthetic
rates under submerged soil conditions. The correlation between biomass and CID was not clear in aerobic soil, whereas it was
positive in submerged soil, which indicated that the significance of lower or higher CID for improving biomass productivity
may differ under different soil water regimes. Overall, the results implied a possible use of CID as a selection criterion
for genotypic improvement inA/T and productivity in rice. 相似文献
8.
Effects of nitrogen deficiency on leaf photosynthetic response of tall fescue to water deficit 总被引:2,自引:2,他引:2
Abstract. The objective of the present work was to study the effect of nitrogen deficiency on drought sensitivity of tall fescue plants. The authors compared photosynthetic and stomatal behaviour of plants grown at either high (8 mol m−3 ) or low (0.5 mol m−3 ) nitrogen levels during a drought cycle followed by rehydration. Other processes investigated were stomatal and non-stomatal inhibition of leaf photosynthesis, water use efficiency and leaf rolling. Plants were grown in pots in controlled conditions on expanded clay. A Wescor in situ hygrometer placed on the leaf base outside the assimilation chamber permitted, simultaneously to leaf gas exchange measurements, monitoring of leaf water potential. Drought was imposed by withholding water from the pot. CO2 uptake and stomatal conductance decreased and leaves started to roll at a lower leaf water potential in the high-N than in the low-N grown plants. Stomatal inhibition of leaf photosynthesis seemed larger in the low-N than in the high-N plants. Water-use efficiency increased more in the high-N than in the low-N grown plants during the drought. The decrease of photosynthesis was largely reversible after rehydration in low-N but not in high-N leaves. The authors suggest that low-N plants avoid water deficit rather than tolerate it. 相似文献
9.
The impacts of various nitrogen sources, i.e. NO−
3, NH4
+ or NH4NO3 in combination with gaseous NH3, on nitrogen-, carbon- and water-use efficiency and 13C discrimination (δ13C) by plants of the C3 species Triticum aestivum L. (wheat) and the C4 species Zea mays L. (maize) were studied. Triticum aestivum and Z. mays were hydroponically grown with 2 mol · m−3 of N supplied as NO−
3, NH4
+ or NH4NO3 for 21 and 18 d, respectively, and thereafter exposed to gaseous NH3 at 320 μg · m−3 or to ambient air for 7 d. In T. aestivum and Z. mays over a 7-d growth period, nitrogen-use efficiency (NUE) values were influenced by N-sources in the decreasing order NH4NO3-N > NO−
3-N > NH4
+-N and NO−
3-N > NH4NO3-N > NH4
+-N, respectively. Fumigation with NH3 decreased the NUE values of plants grown with any of the N-forms. During 28- and 7-d growth periods, N-sources affected water-use
efficiency (WUE) values in the decreasing order of NH4
+-N > NO−
3-N≈NH4NO3-N in non-fumigated T. aestivum, while fumigation with NH3 increased the WUE of NO−
3-grown plants. There were insignificant effects of N-sources on WUE values of Z. mays over 25- and 7-d growth periods. Furthermore, δ13C values in plant tissues (leaves, stubble and roots) were higher (less negative) in NH4
+-grown plants of T. aestivum and Z. mays than in those supplied with NH4NO3 or NO−
3. Regardless of the N-form supplied to the roots of the plant species, exposure to NH3 caused more-positive δ13C values in the plant tissues. These results indicate that the variations in N-source were associated with small but significant
variations in δ13C values in plants of T. aestivum and Z. mays. These differences in δ13C values are in the direction expected from differences in WUE values over long or short growth periods and with differences
in the extent of non-Rubisco (ribulose-1,5-bisphosphate carboxylase-oxygenase, EC 4.1.1.39) carboxylate contribution to net
C acquisition, as a function of N-source.
Received: 12 September 1997 / Accepted: 13 January 1998 相似文献
10.
1. Provenances of Castanea sativa from populations adapted to different climatic areas of Turkey were grown in a field trial in Italy. Carbon isotope discrimination (Δ) in leaf dry matter and in leaf soluble sugar, were measured, along with photosynthesis, stomatal conductance and mesophyll conductance, to study the variability of primary productivity and its ecological significance in European Chestnut.
2. Genetic variations were found in RuBP carboxylase, chlorophyll, leaf soluble protein and leaf thickness.
3. Carbon isotope discrimination (Δ) in leaf dry matter was greater in drought-adapted than in wet-adapted provenances. A similar variation of Δ was observed in leaf soluble carbohydrates either under watered or drought conditions. Possible environmental effects of variables such as vapour pressure difference, on the relationship between transpiration efficiency and carbon isotope discrimination are discussed, on the basis of short-term and long-term results.
4. Generally low values of Δ encountered among provenances were explained not only by low values of intercellular CO2 partial pressure but also by consistently low values of mesophyll conductance leading to reduced chloroplastic CO2 partial pressure. A decrease in mesophyll conductance was induced by water shortage. Co-ordination was found between stomatal and mesophyll conductance, with the drought-adapted provenances showing much higher mesophyll conductance than the wet-adapted provenances. Variations in mesophyll conductance were related to differences in leaf protein content.
5. Possible ecophysiological adaptive mechanisms are discussed taking into account stomatal sensitivity, modulation of photosynthetic capacity and water-use efficiency under drought conditions. 相似文献
2. Genetic variations were found in RuBP carboxylase, chlorophyll, leaf soluble protein and leaf thickness.
3. Carbon isotope discrimination (Δ) in leaf dry matter was greater in drought-adapted than in wet-adapted provenances. A similar variation of Δ was observed in leaf soluble carbohydrates either under watered or drought conditions. Possible environmental effects of variables such as vapour pressure difference, on the relationship between transpiration efficiency and carbon isotope discrimination are discussed, on the basis of short-term and long-term results.
4. Generally low values of Δ encountered among provenances were explained not only by low values of intercellular CO
5. Possible ecophysiological adaptive mechanisms are discussed taking into account stomatal sensitivity, modulation of photosynthetic capacity and water-use efficiency under drought conditions. 相似文献
11.
* A dual-isotope, microcosm experiment was conducted with Quercus rubra (red oak) seedlings to test the hypothesis that foliar herbivory would increase belowground carbon allocation (BCA), carbon (C) rhizodeposition and nitrogen (N) uptake. Plant BCA links soil ecosystems to aboveground processes and can be affected by insect herbivores, though the extent of herbivore influences on BCA is not well understood in woody plants. * Microcosms containing 2-yr-old Q. rubra seedlings and soil collected from the Coweeta Hydrologic Laboratory (NC, USA) were subjected to herbivory or left as undamaged controls. All microcosms were then injected with 15N-glycine and pulsed with 13CO2. * Contrary to our hypothesis, herbivore damage reduced BCA to fine roots by 63% and correspondingly increased allocation of new C to foliage. However, 13C recoveries in soil pools were similar between treatments, suggesting that exudation of C from roots is an actively regulated component of BCA. Herbivore damage also reduced N allocation to fine roots by 39%, apparently in favor of storage in taproot and stem tissues. * Oak seedlings respond to moderate insect herbivore damage with a complex suite of allocation shifts that may simultaneously increase foliar C, maintain C rhizodeposition and N assimilation, and shift N resources to storage. 相似文献
12.
Carbon isotope discrimination and the ratio of carbon gained to water lost in barley cultivars 总被引:13,自引:2,他引:11
Abstract A negative correlation between water-use efficiency (W), defined as the ratio of moles of carbon in the plant to moles of water transpired, and carbon isotope discrimination (Δ) was established for barley in pot experiments using 12 cultivars. The correlation was strong in two independent experiments in four different controlled environment where ambient temperature and vapour pressure deficit were varied and plants were either well-watered or given limited amounts of water. Variation among cultivars was found in both Δ and W and rankings of both parameters, according to cultivar, were similar in different environments. Limiting water usually increased water-use efficiency of plants. Total dry matter can be substituted for moles of carbon when calculating water-use efficiency but the correlation between W and Δ were calculated using the carbon content of dry matter. There were differences varied significantly among cultivars. Despite these differences, correlations were also large between whole plant W and Δ of any of the plant parts. The amount of dry matter partitioned into reproductive growth varied genetically, as did the effect of stress on the partitioning. Growth, W and Δ of barley were compared with theory derived from gas exchange properties and with other literature. The effect on W of variation in vapour pressure deficit in these experiments was removed by multiplying W by vapour pressure deficit to derive the parameter, k(Pa mol C/mol H2O). This allowed comparisons among experiments with different vapour pressure deficits. The mean k for these barley cultivars was similar to that calculated by others for grasses. However, variation was found, and, in contrast with previous work which treats k as a species constant, we conclude that there is promise in selecting for increased k. 相似文献
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A, assimilation ratea, fractionation against 13C for CO2 diffusion through airb, net fractionation against 13C during CO2 fixationCa, ambient CO2 concentrationCc, CO2 concentration at the chloroplastCi, intercellular CO2 concentrationD, vapour pressure deficitEn, needle transpiration rateEp, whole plant water usegw, leaf internal transfer conductance to CO2gs, stomatal conductance to water vapourL, projected leaf areaNUE, nitrogen use efficiencyPEP, phosphoenolpyruvateRubisco, ribulose-1,5-biphosphate carboxylaseTDR, time domain reflectometryWUE, water use efficiencyΔ, carbon isotope discriminationδ13C, carbon isotope abundance parameterδ13Ca, carbon isotopic composition of atmospheric CO2θ, volumetric soil water contentThe effect of nitrogen stress on needle δ13C, water-use efficiency (WUE) and biomass production in irrigated and dry land white spruce (Picea glauca (Moench) Voss) seedlings was investigated. Sixteen hundred seedlings, representing 10 controlled crosses, were planted in the field in individual buried sand-filled cylinders. Two nitrogen treatments were imposed, nitrogen stressed and fertilized. The ranking of δ13C of the crosses was maintained across all combinations of water and nitrogen treatments and there was not a significant genetic versus environmental interaction. The positive relationships between needle δ13C, WUE and dry matter production demonstrate that it should be possible to use δ13C as a surrogate for WUE, and to select for increased WUE without compromising yield, even in nitrogen deficient environments. Nitrogen stressed seedlings had the lowest needle δ13C in both irrigated and dry land conditions. There was a positive correlation between needle nitrogen content and δ13C that was likely associated with increased photosynthetic capacity. There was some indication that decreased nitrogen supply led to increased stomatal conductance and hence lower WUE. There was a negative correlation between intrinsic water use efficiency and photosynthetic nitrogen use efficiency (NUE). This suggests that white spruce seedlings have the ability to maximize NUE when water becomes limited. There was significant genetic variation in NUE that was maintained across treatments. Our results suggest that in white spruce, there is no detectable effect of anaplerotic carbon fixation and that it is more appropriate to use a value of 29‰ (‘Rubisco only’) for the net discrimination against 13C during CO2 fixation. This leads to excellent correspondence between values of Ci/Ca derived from gas exchange measurements or from δ13C. 相似文献
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Effect of leaf structure and water status on carbon isotope discrimination in field-grown durum wheat 总被引:8,自引:0,他引:8
The relationships between leaf and kernel carbon isotope discriminations (Δ) and several leaf structural parameters that are indicators of photosynthetic capacity were studied in durum wheat grown in the field under three water regimens. A set of 144 genotypes were cultivated in two rain-fed trials, and 125 of these were grown under supplementary irrigation before heading. Total chlorophyll and nitrogen (N) contents, the dry mass per unit leaf area (LDM, the reciprocal of specific leaf area) and carbon isotope discrimination (Δ) were measured in penultimate leaves and Δ of mature kernels was also analysed. Both LDM and N per unit area showed significant (P≤ 0.001) negative correlation (r=–0.60 and r=–0.36, respectively) with leaf Δ in the wettest trial. Little or no correlation was found for any structural parameter and leaf Δ in the rain-fed trials. In contrast, in the two rain-fed trials LDM was the parameter with the strongest positive correlation (P≤ 0.001) with kernel Δ (r= 0.47 and 0.30) and grain yield (r= 0.43 and 0.29), whereas no correlation was found in the irrigation trial. These correlations, rather than representing a causal link between the amount of photosynthetic tissue and Δ, were probably indirect associations caused by a parallel effect of water status and phenology on leaf structure, grain Δ and yield. Correlations across trials (i.e. environments) between leaf structure and either Δ and yield were very high, although also spurious. Our results suggest that LDM should be used to cull segregating population differences in leaf Δ based on the internal photosynthetic capacity only in the absence of drought. Selecting for kernel Δ and grain yield on the basis of LDM is worthwhile for rain-fed trials. 相似文献
17.
Effects of water and nitrogen interaction on net photosynthesis, stomatal conductance, and water-use efficiency in two hybrid poplar clones 总被引:2,自引:0,他引:2
We examined the interactions of water and nitrogen availability by subjecting two Populus clones. Tristis and Eugenei, to five soil moisture and three soil nitrogen levels. Nitrogen application significantly increased net photosynthesis and stomatal conductance of flooded Eugenei and Tristis. The onset of flooding caused partial stomatal closure. Net photosynthesis significantly declined after a longer flooding period. Emergence of adventitious roots on the submerged portions of stems in both clones seemingly helped net photosynthesis fully recover in Eugenei and partially recover in Tristis. Under the progressive drought conditions, stomatal conductance was more sensitive to drought than net photosynthesis in both clones. Addition of nitrogen to progressively drying soil induced more stomatal closure in both clones. The highest water-use efficiency was found on the high-N/severe drought zone for Eugenei, whereas it was found on the high-N/mild to moderate drought zone for Tristis. 相似文献
18.
Michelot A Eglin T Dufrêne E Lelarge-Trouverie C Damesin C 《Plant, cell & environment》2011,34(2):230-244
Tree-ring δ(13) C is often interpreted in terms of intrinsic water-use efficiency (WUE) using a carbon isotope discrimination model established at the leaf level. We examined whether intra-ring δ(13) C could be used to assess variations in intrinsic WUE (W(g), the ratio of carbon assimilation and stomatal conductance to water) and variations in ecosystem WUE (W(t) , the ratio of C assimilation and transpiration) at a seasonal scale. Intra-ring δ(13) C was measured in 30- to 60-μm-thick slices in eight oak trees (Quercus petraea). Canopy W(g) was simulated using a physiologically process-based model. High between-tree variability was observed in the seasonal variations of intra-ring δ(13) C. Six trees showed significant positive correlations between W(g) calculated from intra-ring δ(13) C and canopy W(g) averaged over several days during latewood formation. These results suggest that latewood is a seasonal recorder of W(g) trends, with a temporal lag corresponding to the mixing time of sugars in the phloem. These six trees also showed significant negative correlations between photosynthetic discrimination Δ calculated from intra-ring δ(13) C, and ecosystem W(t), during latewood formation. Despite the observed between-tree variability, these results indicate that intra-ring δ(13) C can be used to access seasonal variations in past W(t). 相似文献
19.
Nitrogen transfer among plants in a California oak woodland was examined in a pulse-labeling study using 15N. The study was designed to examine N movement among plants that were mycorrhizal with ectomycorrhizas (EM), arbuscular mycorrhizas (AM), or both. Isotopically enriched N (K15NO3-) was applied to gray pine (Pinus sabiniana) foliage (donor) and traced to neighboring gray pine, blue oak (Quercus douglasii), buckbrush (Ceanothus cuneatus) and herbaceous annuals (Cynosurus echinatus, Torilis arvensis and Trifolium hirtum). After 2 wk, needles of 15N-treated pines and foliage from nearby annuals were similarly enriched, but little 15N had appeared in nontreated (receiver) pine needles, oak leaves or buckbrush foliage. After 4 wk foliar and root samples from pine, oak, buckbrush and annuals were significantly 15N-enriched, regardless of the type of mycorrhizal association. The rate of transfer during the first and second 2-wk periods was similar, and suggests that 15N could continue to be mobilized over longer times. 相似文献