共查询到20条相似文献,搜索用时 31 毫秒
1.
Strong thermal acclimation of photosynthesis in tropical and temperate wet‐forest tree species: the importance of altered Rubisco content
下载免费PDF全文
![点击此处可从《Global Change Biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Benedict M. Long Nur H. A. Bahar Lasantha K. Weerasinghe Danielle Creek John R. Evans Peter B. Reich Owen K. Atkin 《Global Change Biology》2017,23(7):2783-2800
Understanding of the extent of acclimation of light‐saturated net photosynthesis (An) to temperature (T), and associated underlying mechanisms, remains limited. This is a key knowledge gap given the importance of thermal acclimation for plant functioning, both under current and future higher temperatures, limiting the accuracy and realism of Earth system model (ESM) predictions. Given this, we analysed and modelled T‐dependent changes in photosynthetic capacity in 10 wet‐forest tree species: six from temperate forests and four from tropical forests. Temperate and tropical species were each acclimated to three daytime growth temperatures (Tgrowth): temperate – 15, 20 and 25 °C; tropical – 25, 30 and 35 °C. CO2 response curves of An were used to model maximal rates of RuBP (ribulose‐1,5‐bisphosphate) carboxylation (Vcmax) and electron transport (Jmax) at each treatment's respective Tgrowth and at a common measurement T (25 °C). SDS‐PAGE gels were used to determine abundance of the CO2‐fixing enzyme, Rubisco. Leaf chlorophyll, nitrogen (N) and mass per unit leaf area (LMA) were also determined. For all species and Tgrowth, An at current atmospheric CO2 partial pressure was Rubisco‐limited. Across all species, LMA decreased with increasing Tgrowth. Similarly, area‐based rates of Vcmax at a measurement T of 25 °C (Vcmax25) linearly declined with increasing Tgrowth, linked to a concomitant decline in total leaf protein per unit leaf area and Rubisco as a percentage of leaf N. The decline in Rubisco constrained Vcmax and An for leaves developed at higher Tgrowth and resulted in poor predictions of photosynthesis by currently widely used models that do not account for Tgrowth‐mediated changes in Rubisco abundance that underpin the thermal acclimation response of photosynthesis in wet‐forest tree species. A new model is proposed that accounts for the effect of Tgrowth‐mediated declines in Vcmax25 on An, complementing current photosynthetic thermal acclimation models that do not account for T sensitivity of Vcmax25. 相似文献
2.
Photosynthetic parameters in seedlings of Eucalyptus grandis as affected by rate of nitrogen supply 总被引:5,自引:0,他引:5
G. GRASSI P. MEIR R. CROMER D. TOMPKINS & P. G. JARVIS 《Plant, cell & environment》2002,25(12):1677-1688
Seedlings of Eucalyptus grandis were grown at five different rates of nitrogen supply. Once steady‐state growth rates were established, a detailed set of CO2 and water vapour exchange measurements were made to investigate the effects of leaf nitrogen content (N), as determined by nitrogen supply rate, on leaf structural, photosynthetic, respiratory and stomatal properties. Gas exchange data were used to parametrize the Farquhar–von Caemmerer photosynthesis model. Leaf mass per area (LMA) was negatively correlated to N. A positive correlation was observed between both day (Rd) and night respiration (Rn) and N when they were expressed on a leaf mass basis, but no correlation was found on a leaf area basis. An Rd/Rn ratio of 0·59 indicated a significant inhibition of dark respiration by light. The maximum net CO2 assimilation rate at ambient CO2 concentration (Amax), the maximum rate of potential electron transport (Jmax) and the maximum rate of carboxylation (Vcmax) significantly increased with N, particularly when expressed on a mass basis. Although the maximum stomatal conductance to CO2 (gscmax) was positively correlated with Amax, there was no relationship between gscmax and N. Leaf N content influenced the allocation of nitrogen to photosynthetic processes, resulting in a decrease of the Jmax/Vcmax ratio with increasing N. It was concluded that leaf nitrogen concentration is a major determinant of photosynthetic capacity in Eucalyptus grandis seedlings and, to a lesser extent, of leaf respiration and nitrogen partitioning among photosynthetic processes, but not of stomatal conductance. 相似文献
3.
B. Kositsup P. Kasemsap S. Thanisawanyangkura N. Chairungsee D. Satakhun K. Teerawatanasuk T. Ameglio P. Thaler 《Photosynthetica》2010,48(1):67-78
Shoots of the tropical latex-producing tree Hevea brasiliensis (rubber tree) grow according to a periodic pattern, producing four to five whorls of leaves per year. All leaves in the same
whorl were considered to be in the same leaf-age class, in order to assess the evolution of photosynthesis with leaf age in
three clones of rubber trees, in a plantation in eastern Thailand. Light-saturated CO2 assimilation rate (A
max) decreased more with leaf age than did photosynthetic capacity (maximal rate of carboxylation, V
cmax
, and maximum rate of electron transport, J
max), which was estimated by fitting a biochemical photosynthesis model to the CO2-response curves. Nitrogen-use efficiency (A
max/Na, Na is nitrogen content per leaf area) decreased also with leaf age, whereas J
max and V
cmax did not correlate with N
a. Although measurements were performed during the rainy season, the leaf gas exchange parameter that showed the best correlation
with A
max was stomatal conductance (g
s). An asymptotic function was fitted to the A
max-g
s relationship, with R
2 = 0.85. A
max, V
cmax, J
max and g
s varied more among different whorls in the same clone than among different clones in the same whorl. We concluded that leaf
whorl was an appropriate parameter to characterize leaves for the purpose of modelling canopy photosynthesis in field-grown
rubber trees, and that stomatal conductance was the most important variable explaining changes in A
max with leaf age in rubber trees. 相似文献
4.
David S. Ellsworth Peter B. Reich† Elke S. Naumburg‡ George W. Koch§ Mark E. Kubiske¶ Stan D. Smith‡ 《Global Change Biology》2004,10(12):2121-2138
The magnitude of changes in carboxylation capacity in dominant plant species under long‐term elevated CO2 exposure (elevated pCa) directly impacts ecosystem CO2 assimilation from the atmosphere. We analyzed field CO2 response curves of 16 C3 species of different plant growth forms in favorable growth conditions in four free‐air CO2 enrichment (FACE) experiments in a pine and deciduous forest, a grassland and a desert. Among species and across herb, tree and shrub growth forms there were significant enhancements in CO2 assimilation (A) by +40±5% in elevated pCa (49.5–57.1 Pa), although there were also significant reductions in photosynthetic capacity in elevated pCa in some species. Photosynthesis at a common pCa (Aa) was significantly reduced in five species growing under elevated pCa, while leaf carboxylation capacity (Vcmax) was significantly reduced by elevated pCa in seven species (change of ?19±3% among these species) across different growth forms and FACE sites. Adjustments in Vcmax with elevated pCa were associated with changes in leaf N among species, and occurred in species with the highest leaf N. Elevated pCa treatment did not affect the mass‐based relationships between A or Vcmax and N, which differed among herbs, trees and shrubs. Thus, effects of elevated pCa on leaf C assimilation and carboxylation capacity occurred largely through changes in leaf N, rather than through elevated pCa effects on the relationships themselves. Maintenance of leaf carboxylation capacity among species in elevated pCa at these sites depends on maintenance of canopy N stocks, with leaf N depletion associated with photosynthetic capacity adjustments. Since CO2 responses can only be measured experimentally on a small number of species, understanding elevated CO2 effects on canopy Nm and Na will greatly contribute to an ability to model responses of leaf photosynthesis to atmospheric CO2 in different species and plant growth forms. 相似文献
5.
M. E. Kubiske Kurt S. Pregitzer Carl J. Mikan Donald R. Zak Jennifer L. Maziasz A. Teeri 《Oecologia》1997,110(3):328-336
We tested the hypothesis that elevated CO2 would stimulate proportionally higher photosynthesis in the lower crown of Populus trees due to less N retranslocation, compared to tree crowns in ambient CO2. Such a response could increase belowground C allocation, particularly in trees with an indeterminate growth pattern such
as Populus tremuloides. Rooted cuttings of P. tremuloides were grown in ambient and twice ambient (elevated) CO2 and in low and high soil N availability (89 ± 7 and 333 ± 16 ng N g−1 day−1 net mineralization, respectively) for 95 days using open-top chambers and open-bottom root boxes. Elevated CO2 resulted in significantly higher maximum leaf photosynthesis (A
max) at both soil N levels. A
max was higher at high N than at low N soil in elevated, but not ambient CO2. Photosynthetic N use efficiency was higher at elevated than ambient CO2 in both soil types. Elevated CO2 resulted in proportionally higher whole leaf A in the lower three-quarters to one-half of the crown for both soil types. At elevated CO2 and high N availability, lower crown leaves had significantly lower ratios of carboxylation capacity to electron transport
capacity (V
cmax/J
max) than at ambient CO2 and/or low N availability. From the top to the bottom of the tree crowns, V
cmax/J
max increased in ambient CO2, but it decreased in elevated CO2 indicating a greater relative investment of N into light harvesting for the lower crown. Only the mid-crown leaves at both
N levels exhibited photosynthetic down regulation to elevated CO2. Stem biomass segments (consisting of three nodes and internodes) were compared to the total A
leaf for each segment. This analysis indicated that increased A
leaf at elevated CO2 did not result in a proportional increase in local stem segment mass, suggesting that C allocation to sinks other than the
local stem segment increased disproportionally. Since C allocated to roots in young Populus trees is primarily assimilated by leaves in the lower crown, the results of this study suggest a mechanism by which C allocation
to roots in young trees may increase in elevated CO2.
Received: 12 August 1996 / Accepted: 12 November 1996 相似文献
6.
Virtually all current estimates of the maximum carboxylation rate (Vcmax) of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) and the maximum electron transport rate (Jmax) for C3 species implicitly assume an infinite CO2 transfer conductance (gi). And yet, most measurements in perennial plant species or in ageing or stressed leaves show that gi imposes a significant limitation on photosynthesis. Herein, we demonstrate that many current parameterizations of the photosynthesis model of Farquhar, von Caemmerer & Berry (Planta 149, 78–90, 1980 ) based on the leaf intercellular CO2 concentration (Ci) are incorrect for leaves where gi limits photosynthesis. We show how conventional A–Ci curve (net CO2 assimilation rate of a leaf –An– as a function of Ci) fitting methods which rely on a rectangular hyperbola model under the assumption of infinite gi can significantly underestimate Vcmax for such leaves. Alternative parameterizations of the conventional method based on a single, apparent Michaelis–Menten constant for CO2 evaluated at Ci[Km(CO2)i] used for all C3 plants are also not acceptable since the relationship between Vcmax and gi is not conserved among species. We present an alternative A–Ci curve fitting method that accounts for gi through a non‐rectangular hyperbola version of the model of Farquhar et al. (1980 ). Simulated and real examples are used to demonstrate how this new approach eliminates the errors of the conventional A–Ci curve fitting method and provides Vcmax estimates that are virtually insensitive to gi. Finally, we show how the new A–Ci curve fitting method can be used to estimate the value of the kinetic constants of Rubisco in vivo is presented 相似文献
7.
The response of photosynthetic model parameters to temperature and nitrogen concentration in Pinus radiata D. Don 总被引:5,自引:4,他引:1
A. S. WALCROFT D. WHITEHEAD W. B. SILVESTER F. M. KELLIHER 《Plant, cell & environment》1997,20(11):1338-1348
Responses of photosynthesis (A) to intercellular CO2 concentration (ci) in 2-year-old Pinus radiata D. Don seedlings were measured at a range of temperatures in order to parametrize a biophysical model of leaf photosynthesis. Increasing leaf temperature from 8 to 30°C caused a 4-fold increase in Vcmax, the maximum rate of carboxylation (10.7–43.3 μol m?2 s?1 and a 3-fold increase in Jmax, the maximum electron transport rate (20.5–60.2 μmol m ?2 s?1). The temperature optimum for Jmax was lower than that for Vcmax, causing a decline in the ratio Jmax:Vcmax from 2.0 to 1.4 as leaf temperature increased from 8 to 30°C. To determine the response of photosynthesis to leaf nitrogen concentration, additional measurements were made on seedlings grown under four nitrogen treatments. Foliar N concentrations varied between 0.36 and 1.27 mol kg?1, and there were linear relationships between N concentration and both Vcmax and Jmax. Measurements made throughout the crown of a plantation forest tree, where foliar N concentrations varied from 0.83 mol kg?1 near the base to 1.54 mol kg?1 near the leader, yielded similar relationships. These results will be useful in scaling carbon assimilation models from leaves to canopies. 相似文献
8.
In this study, we have examined several physiological, biochemical and morphological features of Buddleja davidii plants growing at 1300 m above sea level (a.s.l.) and 3400 m a.s.l., respectively, to identify coordinated changes in leaf properties in response to reduced CO2 partial pressure (Pa). Our results confirmed previous findings that foliar δ13C, photosynthetic capacity and foliar N concentration on a leaf area basis increased, whereas stomatal conductance (gs) decreased with elevation. The net CO2 assimilation rate (Amax), maximum rate of electron transport (Jmax) and respiration increased significantly with elevation, although no differences were found in carboxylation efficiency of Rubisco (Vcmax). Consequently, also the Jmax to Vcmax ratio was significantly increased by elevation, indicating that the functional balance between Ribulose‐1,5‐biphosphate (RuBP) consumption and RuBP regeneration changes as elevation increases. Our results also indicated a homeostatic response of CO2 transfer conductance inside the leaf (mesophyll conductance, gm) to increasing elevation. In fact, with elevation, gm also increased compensating for the strong decrease in gs and, thus, in the Pi (intercellular partial pressure of CO2) to Pa ratio, leading to similar chloroplast partial pressure of CO2 (Pc) to Pa ratio at different elevations. Because there were no differences in Vcmax, also A measured at similar PPFD and leaf temperature did not differ statistically with elevation. As a consequence, a clear relationship was found between A and gm, and between A and the sum of gs and gm. These data suggest that the higher dry mass δ13C of leaves at the higher elevation, indicative of lower long‐term Pc/Pa ratio, cannot be attributed to changes either in diffusional resistances or in carboxylation efficiency. We speculate that because temperature significantly decreases as the elevation increases, it dramatically affects CO2 diffusion and hence Pc/Pa and, consequently, is the primary factor influencing 13C discrimination at high elevation. 相似文献
9.
Long-term exposure to elevated CO2 concentration will affect the traits of wild plants in association with other environmental factors. We investigated multiple
effects of atmospheric CO2 concentration, irradiance, and soil N availability on the leaf photosynthetic traits of a herbaceous species, Polygonum sachalinense, growing around natural CO2 springs in northern Japan. Atmospheric CO2 concentration and its interaction with irradiance and soil N availability affected several leaf traits. Leaf mass per unit
area increased and N per mass decreased with increasing CO2 and irradiance. Leaf N per area increased with increasing soil N availability at higher CO2 concentrations. The photosynthetic rate under growth CO2 conditions increased with increasing irradiance and CO2, and with increasing soil N at higher CO2 concentrations. The maximal velocity of ribulose 1,5-bisphosphate carboxylation (V
cmax) was affected by the interaction of CO2 and soil N, suggesting that down-regulation of photosynthesis at elevated CO2 was more evident at lower soil N availability. The ratio of the maximum rate of electron transport to V
cmax (J
max/V
cmax) increased with increasing CO2, suggesting that the plants used N efficiently for photosynthesis at high CO2 concentrations by changes in N partitioning. To what extent elevated CO2 influenced plant traits depended on other environmental factors. As wild plants are subject to a wide range of light and
nutrient availability, our results highlight the importance of these environmental factors when the effects of elevated CO2 on plants are evaluated. 相似文献
10.
Y. P. Zheng R. Q. Li L. L. Guo L. H. Hao H. R. Zhou F. Li Z. P. Peng D. J. Cheng M. Xu 《Russian Journal of Plant Physiology》2018,65(4):524-531
Understanding the key processes and mechanisms of photosynthetic and respiratory acclimation of maize (Zea mays L.) plants in response to experimental warming may further shed lights on the changes in the carbon exchange and Net Primary Production (NPP) of agricultural ecosystem in a warmer climate regime. In the current study, we examined the temperature responses and sensitivity of foliar photosynthesis and respiration for exploring the mechanisms of thermal acclimation associated with physiological and biochemical processes in the North China Plain (NCP) with a field manipulative warming experiment. We found that thermal acclimation of An as evidenced by the upward shift of An-T was determined by the maximum velocity of Rubisco carboxylation (Vcmax), the maximum rate of electron transport (Jmax), and the stomatal- regulated CO2 diffusion process (gs), while the balance between respiration and photosynthesis (Rd/Ag), and/or regeneration of RuBP and the Rubisco carboxylation (Jmax/Vcmax) barely affected the thermal acclimation of An. We also found that the temperature response and sensitivity of Rd was closely associated with the changes in foliar N concentration induced by warming. These results suggest that the leaf-level thermal acclimation of photosynthesis and respiration may mitigate or even offset the negative impacts on maize from future climate warming, which should be considered to improve the accuracy of process-based ecosystem models under future climate warming. 相似文献
11.
The mechanisms responsible for photosynthetic acclimation are not well understood, effectively limiting predictability under future conditions. Least‐cost optimality theory can be used to predict the acclimation of photosynthetic capacity based on the assumption that plants maximize carbon uptake while minimizing the associated costs. Here, we use this theory as a null model in combination with multiple datasets of C3 plant photosynthetic traits to elucidate the mechanisms underlying photosynthetic acclimation to elevated temperature and carbon dioxide (CO2). The model‐data comparison showed that leaves decrease the ratio of the maximum rate of electron transport to the maximum rate of Rubisco carboxylation (Jmax/Vcmax) under higher temperatures. The comparison also indicated that resources used for Rubisco and electron transport are reduced under both elevated temperature and CO2. Finally, our analysis suggested that plants underinvest in electron transport relative to carboxylation under elevated CO2, limiting potential leaf‐level photosynthesis under future CO2 concentrations. Altogether, our results show that acclimation to temperature and CO2 is primarily related to resource conservation at the leaf level. Under future, warmer, high CO2 conditions, plants are therefore likely to use less nutrients for leaf‐level photosynthesis, which may impact whole‐plant to ecosystem functioning. 相似文献
12.
Leaf internal diffusion conductance limits photosynthesis more strongly in older leaves of Mediterranean evergreen broad-leaved species 总被引:11,自引:1,他引:11
ÜLO NIINEMETS ALESSANDRO CESCATTI MIRCO RODEGHIERO & TIINA TOSENS 《Plant, cell & environment》2005,28(12):1552-1566
Leaf age-dependent changes in structure, nitrogen content, internal mesophyll diffusion conductance (gm), the capacity for photosynthetic electron transport (Jmax) and the maximum carboxylase activity of Rubisco (Vcmax) were investigated in mature non-senescent leaves of Laurus nobilis L., Olea europea L. and Quercus ilex L. to test the hypothesis that the relative significance of biochemical and diffusion limitations of photosynthesis changes with leaf age. The leaf life-span was up to 3 years in L. nobilis and O. europea and 6 years in Q. ilex. Increases in leaf age resulted in enhanced leaf dry mass per unit area (MA), larger leaf dry to fresh mass ratio, and lower nitrogen contents per dry mass (NM) in all species, and lower nitrogen contents per area (NA) in L. nobilis and Q. ilex. Older leaves had lower gm, Jmax and Vcmax. Due to the age-dependent increase in MA, mass-based gm, Jmax and Vcmax declined more strongly (7- to 10-fold) with age than area-based (5- to 7-fold) characteristics. Diffusion conductance was positively associated with foliage photosynthetic potentials. However, this correlation was curvilinear, leading to lower ratio of chloroplastic to internal CO2 concentration (Cc/Ci) and larger drawdown of CO2 from leaf internal air space to chloroplasts (ΔC) in older leaves with lower gm. Overall the age-dependent decreases in photosynthetic potentials were associated with decreases in NM and in the fraction of N in photosynthetic proteins, whereas decreases in gm were associated with increases in MA and the fraction of cell walls. These age-dependent modifications altered the functional scaling of foliage photosynthetic potentials with MA, NM, and NA. The species primarily differed in the rate of age-dependent modifications in foliage structural and functional characteristics, but also in the degree of age-dependent changes in various variables. Stomatal openness was weakly associated with leaf age, but due to species differences in stomatal openness, the distribution of total diffusion limitation between stomata and mesophyll varied among species. These data collectively demonstrate that in Mediterranean evergreens, structural limitations of photosynthesis strongly interact with biochemical limitations. Age-dependent changes in gm and photosynthetic capacities do not occur in a co-ordinated manner in these species such that mesophyll diffusion constraints curb photosynthesis more in older than in younger leaves. 相似文献
13.
In this study, we tested for the temporal occurrence of photosynthetic acclimation to elevated [CO2] in the flag leaf of two important cereal crops, rice and wheat. In order to characterize the temporal onset of acclimation and the basis for any observed decline in photosynthetic rate, we characterized net photosynthesis, gs, gm, Ci/Ca, Ci/Cc, Vcmax, Jmax, cell wall thickness, content of Rubisco, cytochrome (Cyt) f, N, chlorophyll and carbohydrate, mRNA expression for rbcL and petA, activity for Rubisco, sucrose phosphate synthase (SPS) and sucrose synthase (SS) at full flag expansion, mid‐anthesis and the late grain‐filling stage. No acclimation was observed for either crop at full flag leaf expansion. However, at the mid‐anthesis stage, photosynthetic acclimation in rice was associated with RuBP carboxylation and regeneration limitations, while wheat only had the carboxylation limitation. By grain maturation, the decline of Rubisco content and activity had contributed to RuBP carboxylation limitation of photosynthesis in both crops at elevated [CO2]; however, the sharp decrease of Rubisco enzyme activity played a more important role in wheat. Although an increase in non‐structural carbohydrates did occur during these later stages, it was not consistently associated with changes in SPS and SS or photosynthetic acclimation. Rather, over time elevated [CO2] appeared to enhance the rate of N degradation and senescence so that by late‐grain fill, photosynthetic acclimation to elevated [CO2] in the flag leaf of either species was complete. These data suggest that the basis for photosynthetic acclimation with elevated [CO2] may be more closely associated with enhanced rates of senescence, and, as a consequence, may be temporally dynamic, with significant species variation. 相似文献
14.
ZEWEI MIAO MING XU RICHARD G. LATHROP JR. & YUFEI WANG 《Plant, cell & environment》2009,32(2):109-122
A review of the literature revealed that a variety of methods are currently used for fitting net assimilation of CO2–chloroplastic CO2 concentration (A–Cc) curves, resulting in considerable differences in estimating the A–Cc parameters [including maximum ribulose 1·5‐bisphosphate carboxylase/oxygenase (Rubisco) carboxylation rate (Vcmax), potential light saturated electron transport rate (Jmax), leaf dark respiration in the light (Rd), mesophyll conductance (gm) and triose‐phosphate utilization (TPU)]. In this paper, we examined the impacts of fitting methods on the estimations of Vcmax, Jmax, TPU, Rd and gm using grid search and non‐linear fitting techniques. Our results suggested that the fitting methods significantly affected the predictions of Rubisco‐limited (Ac), ribulose 1,5‐bisphosphate‐limited (Aj) and TPU‐limited (Ap) curves and leaf photosynthesis velocities because of the inconsistent estimate of Vcmax, Jmax, TPU, Rd and gm, but they barely influenced the Jmax : Vcmax, Vcmax : Rd and Jmax : TPU ratio. In terms of fitting accuracy, simplicity of fitting procedures and sample size requirement, we recommend to combine grid search and non‐linear techniques to directly and simultaneously fit Vcmax, Jmax, TPU, Rd and gm with the whole A–Cc curve in contrast to the conventional method, which fits Vcmax, Rd or gm first and then solves for Vcmax, Jmax and/or TPU with Vcmax, Rd and/or gm held as constants. 相似文献
15.
The relationship of leaf photosynthetic traits – Vcmax and Jmax – to leaf nitrogen,leaf phosphorus,and specific leaf area: a meta‐analysis and modeling study
下载免费PDF全文
![点击此处可从《Ecology and evolution》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anthony P. Walker Andrew P. Beckerman Lianhong Gu Jens Kattge Lucas A. Cernusak Tomas F. Domingues Joanna C. Scales Georg Wohlfahrt Stan D. Wullschleger F. Ian Woodward 《Ecology and evolution》2014,4(16):3218-3235
Great uncertainty exists in the global exchange of carbon between the atmosphere and the terrestrial biosphere. An important source of this uncertainty lies in the dependency of photosynthesis on the maximum rate of carboxylation (Vcmax) and the maximum rate of electron transport (Jmax). Understanding and making accurate prediction of C fluxes thus requires accurate characterization of these rates and their relationship with plant nutrient status over large geographic scales. Plant nutrient status is indicated by the traits: leaf nitrogen (N), leaf phosphorus (P), and specific leaf area (SLA). Correlations between Vcmax and Jmax and leaf nitrogen (N) are typically derived from local to global scales, while correlations with leaf phosphorus (P) and specific leaf area (SLA) have typically been derived at a local scale. Thus, there is no global-scale relationship between Vcmax and Jmax and P or SLA limiting the ability of global-scale carbon flux models do not account for P or SLA. We gathered published data from 24 studies to reveal global relationships of Vcmax and Jmax with leaf N, P, and SLA. Vcmax was strongly related to leaf N, and increasing leaf P substantially increased the sensitivity of Vcmax to leaf N. Jmax was strongly related to Vcmax, and neither leaf N, P, or SLA had a substantial impact on the relationship. Although more data are needed to expand the applicability of the relationship, we show leaf P is a globally important determinant of photosynthetic rates. In a model of photosynthesis, we showed that at high leaf N (3 gm−2), increasing leaf P from 0.05 to 0.22 gm−2 nearly doubled assimilation rates. Finally, we show that plants may employ a conservative strategy of Jmax to Vcmax coordination that restricts photoinhibition when carboxylation is limiting at the expense of maximizing photosynthetic rates when light is limiting. 相似文献
16.
The limiting step of photosynthesis changes depending on CO2 concentration and, in theory, photosynthetic nitrogen use efficiency at a respective CO2 concentration is maximized if nitrogen is redistributed from non‐limiting to limiting processes. It has been shown that some plants increase the capacity of ribulose‐1,5‐bisphoshate (RuBP) regeneration (evaluated as Jmax) relative to the RuBP carboxylation capacity (evaluated as Vcmax) at elevated CO2, which is in accord with the theory. However, there is no study that tests whether this change is accompanied by redistribution of nitrogen in the photosynthetic apparatus. We raised a perennial plant, Polygonum sachalinense, at two nutrient availabilities under two CO2 concentrations. The Jmax to Vcmax ratio significantly changed with CO2 increment but the nitrogen allocation among the photosynthetic apparatus did not respond to growth CO2. Enzymes involved in RuBP regeneration might be more activated at elevated CO2, leading to the higher Jmax to Vcmax ratio. Our result suggests that nitrogen partitioning is not responsive to elevated CO2 even in species that alters the balance between RuBP regeneration and carboxylation. Nitrogen partitioning seems to be conservative against changes in growth CO2 concentration. 相似文献
17.
Hemp (Cannabis sativa L.) leaf photosynthesis in relation to nitrogen content and temperature: implications for hemp as a bio‐economically sustainable crop
下载免费PDF全文
![点击此处可从《Global Change Biology Bioenergy》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kailei Tang Paul C. Struik Stefano Amaducci Tjeerd‐Jan Stomph Xinyou Yin 《Global Change Biology Bioenergy》2017,9(10):1573-1587
Hemp (Cannabis sativa L.) may be a suitable crop for the bio‐economy as it requires low inputs while producing a high and valuable biomass yield. With the aim of understanding the physiological basis of hemp's high resource‐use efficiency and yield potential, photosynthesis was analysed on leaves exposed to a range of nitrogen and temperature levels. Light‐saturated net photosynthesis rate (Amax) increased with an increase in leaf nitrogen up to 31.2 ± 1.9 μmol m?2 s?1 at 25 °C. The Amax initially increased with an increase in leaf temperature (TL), levelled off at 25–35 °C and decreased when TL became higher than 35 °C. Based on a C3 leaf photosynthesis model, we estimated mesophyll conductance (gm), efficiency of converting incident irradiance into linear electron transport under limiting light (κ2LL), linear electron transport capacity (Jmax), Rubisco carboxylation capacity (Vcmax), triose phosphate utilization capacity (Tp) and day respiration (Rd), using data obtained from gas exchange and chlorophyll fluorescence measurements at different leaf positions and various levels of incident irradiance, CO2 and O2. The effects of leaf nitrogen and temperature on photosynthesis parameters were consistent at different leaf positions and among different growth environments except for κ2LL, which was higher for plants grown in the glasshouse than for those grown outdoors. Model analysis showed that compared with cotton and kenaf, hemp has higher photosynthetic capacity when leaf nitrogen is <2.0 g N m?2. The high photosynthetic capacity measured in this study, especially at low nitrogen level, provides additional evidence that hemp can be grown as a sustainable bioenergy crop over a wide range of climatic and agronomic conditions. 相似文献
18.
JEAN‐MARC LIMOUSIN LAURENT MISSON ANNE‐VIOLETTE LAVOIR NICOLAS K. MARTIN SERGE RAMBAL 《Plant, cell & environment》2010,33(5):863-875
Seasonal drought can severely impact leaf photosynthetic capacity. This is particularly important for Mediterranean forests, where precipitation is expected to decrease as a consequence of climate change. Impacts of increased drought on the photosynthetic capacity of the evergreen Quercus ilex were studied for two years in a mature forest submitted to long‐term throughfall exclusion. Gas exchange and chlorophyll fluorescence were measured on two successive leaf cohorts in a control and a dry plot. Exclusion significantly reduced leaf water potential in the dry treatment. In both treatments, light‐saturated net assimilation rate (Amax), stomatal conductance (gs), maximum carboxylation rate (Vcmax), maximum rate of electron transport (Jmax), mesophyll conductance to CO2 (gm) and nitrogen investment in photosynthesis decreased markedly with soil water limitation during summer. The relationships between leaf photosynthetic parameters and leaf water potential remained identical in the two treatments. Leaf and canopy acclimation to progressive, long‐term drought occurred through changes in leaf area index, leaf mass per area and leaf chemical composition, but not through modifications of physiological parameters. 相似文献
19.
Egea G González-Real MM Baille A Nortes PA Diaz-Espejo A 《Plant, cell & environment》2011,34(6):962-979
Very few studies have attempted to disentangle the respective role of ontogeny and water stress on leaf photosynthetic attributes. The relative significance of both effects on photosynthetic attributes has been investigated in leaves of field‐grown almond trees [Prunus dulcis (Mill.) D. A. Webb] during four growth cycles. Leaf ontogeny resulted in enhanced leaf dry weight per unit area (Wa), greater leaf dry‐to‐fresh weight ratio and lower N content per unit of leaf dry weight (Nw). Concomitantly, area‐based maximum carboxylation rate (Vcmax), maximum electron transport rate (Jmax), mesophyll conductance to CO2 diffusion (gm)′ and light‐saturated net photosynthesis (Amax) declined in both well‐watered and water‐stressed almond leaves. Although gm and stomatal conductance (gs) seemed to be co‐ordinated, a much stronger coordination in response to ontogeny and prolonged water stress was observed between gm and the leaf photosynthetic capacity. Under unrestricted water supply, the leaf age‐related decline of Amax was equally driven by diffusional and biochemical limitations. Under restricted soil water availability, Amax was mainly limited by gs and, to a lesser extent, by photosynthetic capacity and gm. When both ontogeny and water stress effects were combined, diffusional limitations was the main determinant of photosynthesis limitation, while stomatal and biochemical limitations contributed similarly. 相似文献
20.
Stomatal closure and metabolic impairment under drought stress limits photosynthesis. The objective of this study was to determine major stomatal and metabolic factors involved in photosynthetic responses to drought and recovery upon re‐watering in a C3 perennial grass species, Kentucky bluegrass (Poa pratensis L.). Two genotypes differing in drought resistance, ‘Midnight’ (tolerant) and ‘Brilliant’ (sensitive), were subjected to drought stress for 15 days and then re‐watered for 10 days in growth chambers. Single‐leaf net photosynthetic rate (A), stomatal conductance (gs) and transpiration rate (Tr) decreased during drought, with a less rapid decline in ‘Midnight’ than in ‘Brilliant’. Photochemical efficiency, Rubisco activity and activation state declined during drought, but were significantly higher in ‘Midnight’ than in ‘Brilliant’. The relationship between A and internal leaf CO2 concentration (A/Ci curve) during drought and re‐watering was analyzed to estimate the relative influence of stomatal and non‐stomatal components on photosynthesis. Stomatal limitation (Ls %), non‐stomatal limitation (Lns %), CO2 compensation point (CP) and dark respiration (Rd) increased with stress duration in both genotypes, but to a lesser extent in ‘Midnight’. Maximum CO2 assimilation rate (Amax), carboxylation efficiency (CE) and mesophyll conductance (gm) declined, but ‘Midnight’ had significantly higher levels of Amax, CE and gm than ‘Brilliant’. Maximum carboxylation rate of Rubisco (Vcmax) and ribulose‐1,5‐bisphospate (RuBP) regeneration capacity mediated by maximum electron transport rate (Jmax) decreased from moderate to severe drought stress in both genotypes, but to a greater extent in ‘Brilliant’ than in ‘Midnight’. After re‐watering, RWC restored to about 90% of the control levels in both genotypes, whereas A, gs, Tr and Fv/Fm was only partially recovered, with a higher recovery level in ‘Midnight’ than in ‘Brilliant’. Rubisco activity and activation state restored to the control level after re‐watering, with more rapid increase in ‘Midnight’ than in ‘Brilliant’. The values of Ls, Lns, CP and Rd declined, and Amax, CE, Vcmax, Jmax and gm increased after re‐watering, with more rapid change in all parameters in ‘Midnight’ than in ‘Brilliant’. These results indicated that the maintenance of higher A and Amax under drought stress in drought‐tolerant Kentucky bluegrass could be attributed to higher Rubico activation state, higher CE and less stomatal limitation. The ability to resume metabolic activity (Amax, CE, Fv/Fm and Rubisco) was observed in the drought‐tolerant genotype and is the most likely cause for the increased recuperative ability of photosynthesis. Incomplete recovery of photosynthesis upon re‐watering could be attributable to lasting stomatal limitations caused by severe drought damage in both genotypes. Promoting rapid stomatal recovery from drought stress may be critical for plants to resume full photosynthetic capacity in C3 perennial grass species. 相似文献