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141.
Photosynthetic nitrogen-use efficiency of species that differ inherently in specific leaf area 总被引:42,自引:0,他引:42
Factors that contribute to interspecific variation in photosynthetic nitrogen-use efficiency (PNUE, the ratio of CO2 assimilation rate to leaf organic nitrogen content) were investigated, comparing ten dicotyledonous species that differ inherently
in specific leaf area (SLA, leaf area:leaf dry mass). Plants were grown hydroponically in controlled environment cabinets
at two irradiances (200 and 1000 μmol m–2 s–1). CO2 and irradiance response curves of photosynthesis were measured followed by analysis of the chlorophyll, Rubisco, nitrate
and total nitrogen contents of the leaves. At both irradiances, SLA ranged more than twofold across species. High-SLA species
had higher in situ rates of photosynthesis per unit leaf mass, but similar rates on an area basis. The organic N content per
unit leaf area was lower for the high-SLA species and consequently PNUE at ambient light conditions (PNUEamb) was higher in those plants. Differences were somewhat smaller, but still present, when PNUE was determined at saturating
irradiances (PNUEmax). An assessment was made of the relative importance of the various factors that underlay interspecific variation in PNUE.
For plants grown under low irradiance, PNUEamb of high-SLA species was higher primarily due to their lower N content per unit leaf area. Low-SLA species clearly had an
overinvestment in photosynthetic N under these conditions. In addition, high SLA-species allocated a larger fraction of organic
nitrogen to thylakoids and Rubisco, which further increased PNUEamb. High-SLA species grown under high irradiance showed higher PNUEamb mainly due to a higher Rubisco specific activity. Other factors that contributed were again their lower contents of Norg per unit leaf area and a higher fraction of photosynthetic N in electron transport and Rubisco. For PNUEmax, differences between species in organic leaf nitrogen content per se were no longer important and higher PNUEmax of the high SLA species was due to a higher fraction of N in␣photosynthetic compounds (for low-light plants) and a higher
Rubisco specific activity (for high-light grown plants).
Received: 11 October 1997 / Accepted: 9 April 1998 相似文献
142.
Sprikkelman Aline B.; Van Eykern Leo A.; Lourens Marlies S.; Heymans Hugo S.A.; Van Aalderen Wim M.C. 《Journal of applied physiology》1998,84(3):897-901
We investigatedwhether an increase in transcutaneous electromyographic (EMG) activityof the diaphragm and intercostal muscles corresponds with theconcentration of histamine that induces a 20% fall in the forcedexpiratory volume in one second(FEV1; PC20). Eleven asthmatic children(mean age 11.9 yr) were studied after they were given histaminechallenge. EMG activity atPC20 or at the highest histamineconcentration was compared with activity at baseline by calculating theratio of the mean peak-to-peak excursion at the highest histamine doseto that at baseline [EMG activity ratio (EMGAR)]. In allchildren reaching PC20, anincrease in diaphragmatic and intercostal EMGAR was observed. Noincrease was found at the dose step beforePC20 was reached. In sixchallenges, no fall in FEV1 wasinduced, and no increase in EMGAR was seen. In two challenges, no fallin FEV1 was induced, but increasein diaphragmatic or intercostal EMGAR was observed. Increase in the electrical activity of the diaphragm and intercostal muscles in asthmatic children corresponds closely to a 20% fall inFEV1 induced by histaminechallenge. 相似文献
143.
Architecture and leaf display were compared in saplings of six rain forest tree species differing in shade tolerance. Saplings were selected along the whole light range encountered in a forest environment. Species differed largely in realized height and crown expansion per unit support biomass, but this could not be related to differences in shade tolerance. The results demonstrate that there exist various solutions to an effective expansion of plant height and crown area. It is argued that choice of the study species and the ontogenetic trajectory regarded determine to a large extent the outcome of interspecific comparisons. No evidence was found that pioneers were characterized by a multilayered and shade tolerants by a monolayered leaf distribution. Yet, sun plants had a similar crown area, a deeper crown, and a higher leaf area index compared to shade plants and their leaves were more evenly distributed along the stem. This suggests that differences in leaf layering are found between plants growing in different light environments, rather than between species differing in shade tolerance. 相似文献
144.
Interspecific variation in the growth response of plants to an elevated ambient CO2 concentration 总被引:10,自引:0,他引:10
The effect of a doubling in the atmospheric CO2 concentration on the growth of vegetative whole plants was investigated. In a compilation of literature sources, the growth stimulation of 156 plant species was found to be on average 37%. This enhancement is small compared to what could be expected on the basis of CO2-response curves of photosynthesis. The causes for this stimulation being so modest were investigated, partly on the basis of an experiment with 10 wild plant species. Both the source-sink relationship and size constraints on growth can cause the growth-stimulating effect to be transient.Data on the 156 plant species were used to explore interspecific variation in the response of plants to high CO2. The growth stimulation was larger for C3 species than for C4 plants. However the difference in growth stimulation is not as large as expected as C4 plants also significantly increased in weight (41% for C3
vs. 22% for C4). The few investigated CAM species were stimulated less in growth (15%) than the average C4 species. Within the group of C3 species, herbaceous crop plants responded more strongly than herbaceous wild species (58%vs. 35%) and potentially fast-growing wild species increased more in weight than slow-growing species (54%vs. 23%). C3 species capable of symbiosis with N2-fixing organisms had higher growth stimulations compared to other C3 species. A common denominator in these 3 groups of more responsive C3 plants might be their large sink strength. Finally, there was some tendency for herbaceous dicots to show a larger response than monocots. Thus, on the basis of this literature compilation, it is concluded that also within the group of C3 species differences exist in the growth response to high CO2.Abbreviations LAR
leaf area ratio
- LWR
leaf weight ratio
- NAR
net assimilation rate
- PSa
rate of photosynthesis per unit leaf area
- RGR
relative growth rate
- RWR
root weight ratio
- SLA
specific leaf area 相似文献
145.
Plant growth analysis: towards a synthesis of the classical and the functional approach 总被引:9,自引:0,他引:9
Hendrik Poorter 《Physiologia plantarum》1989,75(2):237-244
A method of calculating relative growth rates (RGR) and net assimilation rates is presented. The method is based on the fitting of a polynomial through the relative growth rate values calculated by the 'classical' approach rather than through the In-transformed plant weights as in the 'functional' method. Additional ways of reducing the harvest-to-harvest variation characteristic of the classical approach are discussed. The main advantages of the present approach over the functional one are: (1) The degree of the polynomial can be increased (within certain limits) without inducing spurious fluctuations in RGR. Thus, quite complex trends in RGR can be described. (2) There is little interference between RGR values in different parts of the experiment. The main advantages over the classical approach are: (1) The erratic fluctuations in RGR are dampened. (2) As frequent small harvests are allowed, the workload at each harvest can be diminished and a more reliable impression of ontogenetic drift in RGR can be obtained. (3) RGR is described by a continuous function, thus facilitating further calculations and compilations. 相似文献
146.
W. A. Stirk G. D. Arthur A. F. Lourens O. Novák M. Strnad J. van Staden 《Journal of applied phycology》2004,16(1):31-39
Two seaweed concentrates were made from the kelps Ecklonia maxima and Macrocystis pyrifera using a cell burst method. Cytokinin- and auxin-like activities were measured using the soybean callus and mungbean bioassays,
respectively. Cytokinin-like activity was detected in both seaweed concentrates, being equivalent to approximately 50 μg L−1 kinetin. Auxin-like activity was also detected in both concentrates with the E. maxima derived concentrate having higher biological activity, equivalent to 10−5–10−4 M indole-butyric acid. Two replicates of each concentrate were stored at 54 °C for 14 days to accelerate the effects of storage.
Both fresh and stored samples of the two seaweed concentrates were analysed for their endogenous cytokinin and auxin content.
The samples were purified using a combined DEAE-Sephadex octadecylsilica column and immunoaffinity chromatography based on
wide-range cytokinin and IAA specific monoclonal antibodies. These extracts were analysed by HPLC linked to a Micromass single
quadrupole mass spectrophotometer. Eighteen and nineteen different cytokinins were detected, respectively, in the two concentrates,
with trans-zeatin-O-glucoside being the main cytokinin present. Accelerated storage of the concentrates caused an increase in the total
cytokinin concentration with a large increase in the aromatic meta-topolin. Indole-3-acetic acid was the main auxin in both seaweed concentrates. Indole conjugates, including amino acid conjugates,
were also quantified. The total auxin concentration decreased with accelerated storage for both concentrates.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
147.
Light partitioning is thought to contribute to the coexistence of rain forest tree species. This study evaluates the three
premises underlying the light partitioning hypothesis; 1) there is a gradient in light availability at the forest floor, 2)
tree species show a differential distribution with respect to light, and 3) there is a trade-off in species performance that
explains their different positions along the light gradient. To address these premises, we studied the light environment,
growth, and survival of saplings of ten non-pioneer tree species in a Bolivian moist forest. Light availability in the understorey
was relatively high, with a mean canopy openness of 3.5% and a mean direct site factor of 6.8%. Saplings of two light demanding
species occurred at significantly higher light levels than the shade tolerant species. The proportion of saplings in low-light
conditions was negatively correlated with the successional position of the species. Light-demanding species were characterised
by a low share of their saplings in low-light conditions, a high sapling mortality, a fast height growth and a strong growth
response to light. These data show that all three premises for light partitioning are met. There is a clear gradient in shade-tolerance
within the group of non-pioneer species leading to a tight packing of species along the small range of light environments
found in the understorey.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
148.
Photosynthetic acclimation of plants to growth irradiance: the relative importance of specific leaf area and nitrogen partitioning in maximizing carbon gain 总被引:28,自引:5,他引:23
Changes in specific leaf area (SLA, projected leaf area per unit leaf dry mass) and nitrogen partitioning between proteins within leaves occur during the acclimation of plants to their growth irradiance. In this paper, the relative importance of both of these changes in maximizing carbon gain is quantified. Photosynthesis, SLA and nitrogen partitioning within leaves was determined from 10 dicotyledonous C3 species grown in photon irradiances of 200 and 1000 µmol m?2 s?1. Photosynthetic rate per unit leaf area measured under the growth irradiance was, on average, three times higher for high‐light‐grown plants than for those grown under low light, and two times higher when measured near light saturation. However, light‐saturated photosynthetic rate per unit leaf dry mass was unaltered by growth irradiance because low‐light plants had double the SLA. Nitrogen concentrations per unit leaf mass were constant between the two light treatments, but plants grown in low light partitioned a larger fraction of leaf nitrogen into light harvesting. Leaf absorptance was curvilinearly related to chlorophyll content and independent of SLA. Daily photosynthesis per unit leaf dry mass under low‐light conditions was much more responsive to changes in SLA than to nitrogen partitioning. Under high light, sensitivity to nitrogen partitioning increased, but changes in SLA were still more important. 相似文献
149.
Allometric equations for integrating remote sensing imagery into forest monitoring programmes 总被引:2,自引:0,他引:2
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Tommaso Jucker John Caspersen Jérôme Chave Cécile Antin Nicolas Barbier Frans Bongers Michele Dalponte Karin Y. van Ewijk David I. Forrester Matthias Haeni Steven I. Higgins Robert J. Holdaway Yoshiko Iida Craig Lorimer Peter L. Marshall Stéphane Momo Glenn R. Moncrieff Pierre Ploton Lourens Poorter Kassim Abd Rahman Michael Schlund Bonaventure Sonké Frank J. Sterck Anna T. Trugman Vladimir A. Usoltsev Mark C. Vanderwel Peter Waldner Beatrice M. M. Wedeux Christian Wirth Hannsjörg Wöll Murray Woods Wenhua Xiang Niklaus E. Zimmermann David A. Coomes 《Global Change Biology》2017,23(1):177-190
Remote sensing is revolutionizing the way we study forests, and recent technological advances mean we are now able – for the first time – to identify and measure the crown dimensions of individual trees from airborne imagery. Yet to make full use of these data for quantifying forest carbon stocks and dynamics, a new generation of allometric tools which have tree height and crown size at their centre are needed. Here, we compile a global database of 108753 trees for which stem diameter, height and crown diameter have all been measured, including 2395 trees harvested to measure aboveground biomass. Using this database, we develop general allometric models for estimating both the diameter and aboveground biomass of trees from attributes which can be remotely sensed – specifically height and crown diameter. We show that tree height and crown diameter jointly quantify the aboveground biomass of individual trees and find that a single equation predicts stem diameter from these two variables across the world's forests. These new allometric models provide an intuitive way of integrating remote sensing imagery into large‐scale forest monitoring programmes and will be of key importance for parameterizing the next generation of dynamic vegetation models. 相似文献
150.
Lourens Poorter Masha T. van der Sande Eric J. M. M. Arets Nataly Ascarrunz Brian J. Enquist Bryan Finegan Juan Carlos Licona Miguel Martínez‐Ramos Lucas Mazzei Jorge A. Meave Rodrigo Muñoz Christopher J. Nytch Alexandre A. de Oliveira Eduardo A. Pérez‐García Jamir Prado‐Junior Jorge Rodríguez‐Velázques Ademir Roberto Ruschel Beatriz Salgado‐Negret Ivan Schiavini Nathan G. Swenson Elkin A. Tenorio Jill Thompson Marisol Toledo Maria Uriarte Peter van der Hout Jess K. Zimmerman Marielos Peña‐Claros 《Global Ecology and Biogeography》2017,26(12):1423-1434