scholarly journals PHOTOSYNTHESIS OF BIRCH TAXA (Betula L.) UNDER VARIED IRRADIANCE AND CO2 CONCENTRATION

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 882e-883
Author(s):  
Mengmeng Gu ◽  
Curt R. Rom ◽  
James A. Robbins ◽  
Hyun-Sug Choi
Keyword(s):  
Response Curve ◽  
Light Response ◽  
Co2 Concentration ◽  
Betula Alleghaniensis ◽  
Light Response Curve ◽  
Deciduous Species ◽  
Exchange System ◽  
High Co2 ◽  
Gas Exchange System ◽  
Ambient Co2

The genus Betula consists of approximately 50 deciduous species throughout northern hemisphere. Net CO2 assimilation ([A]) of four birch taxa (Betula alleghaniensis Britton, B. davurica Pall., B. nigra L. `Heritage', and B. papyrifera Marsh.) was measured with a portable gas exchange system, CIRAS-I. Light was increased from 0 to 2000 μmol· m-2·s-1 at increments of 25, 50, 100, 250, 500, 750, 1000, 1250, 1500, 1750, 2000 μmol·m–2·s–1 to create an [A] light-response curve. CO2 concentration was gradually increased to 1100 ppm in increments 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100 ppm to create an [A]-Ca (ambient CO2) curve. B. davurica had significantly higher potential A capacity than the other taxa under high CO2 conditions. Betula nigra `Heritage' had the highest carboxylation efficiency among four taxa. B. davurica and B. nigra `Heritage', had higher [A] when ambient CO2 is 0ppm. Betula davurica and B. nigra `Heritage', had higher light-saturated rate of gross [A] than B. alleghaniensis and B. papyrifera.

Comparison between modified exponential model and common models of light-response curve

2013 ◽  
Vol 36 (12) ◽  
pp. 1277-1285 ◽  
Author(s):  
Wei-Ying CHEN ◽  
Zhen-Yong CHEN ◽  
Fu-Yan LUO ◽  
Zheng-Song PENG ◽  
Mao-Qun YU
Keyword(s):  
Response Curve ◽  
Light Response ◽  
Exponential Model ◽  
Light Response Curve

The Photosynthesis-Light Response Curve

1992 ◽  
pp. 156-191 ◽  
Author(s):  
Richard J. Geider ◽  
Bruce A. Osborne
Keyword(s):  
Response Curve ◽  
Light Response ◽  
Light Response Curve

The impacts of leaf shape and arrangement on light interception and potential photosynthesis in southern beech (Nothofagus cunninghamii)

2004 ◽  
Vol 31 (5) ◽  
pp. 471 ◽  
Author(s):  
Stephen O. Kern ◽  
Mark J. Hovenden ◽  
Gregory J. Jordan
Keyword(s):  
Flux Density ◽  
Response Curve ◽  
Leaf Shape ◽  
Carbon Assimilation ◽  
Light Response ◽  
Light Interception ◽  
Photon Flux ◽  
Assimilation Rate ◽  
Light Response Curve ◽  
Carbon Assimilation Rate

The impact of differences in leaf shape, size and arrangement on the efficiency of light interception, and in particular the avoidance of photoinhibition, are poorly understood. We therefore estimated light exposure of branches in the cool temperate rainforest tree, Nothofagus cunninghamii (Hook.) Oerst., in which leaf shape, size and arrangement vary systematically with altitude and geographic origin. Measurements of incident photosynthetic photon flux density (PPFD) were made in the laboratory at solar angles corresponding to noon at summer solstice, winter solstice and equinox on branches collected from a common garden experiment. Tasmanian plants showed more self-shading than Victorian plants in summer and equinox. This was related to branch angle, leaf arrangement and leaf shape. Using a modelled light response-curve, we estimated the carbon assimilation rate and the flux density of excess photons at different incident PPFD. Victorian plants had higher predicted assimilation rates than Tasmanian plants in summer and equinox, but were exposed to substantially greater levels of excess photons. Because of the shape of the light-response curve, self-shading appears to reduce the plant's exposure to excess photons, thus providing photoprotection, without substantially reducing the carbon assimilation rate. This is dependent on both regional origin and season.

Regulation of Carboxylation and Photosynthetic Oscillations During Sun-Shade Acclimation in Helianthus annuus Measured With a Rapid-Response Gas Exchange System

1988 ◽  
Vol 15 (2) ◽  
pp. 239 ◽  
Author(s):  
CB Osmond ◽  
V Oja ◽  
A Laisk
Keyword(s):  
Gas Exchange ◽  
Intercellular Co2 Concentration ◽  
Photosynthetic Apparatus ◽  
Co2 Concentration ◽  
Rapid Response ◽  
Exchange System ◽  
Dynamic Regulation ◽  
Bisphosphate Carboxylase ◽  
Shade Acclimation ◽  
Gas Exchange System

The consequences of acclimation from shade to sun and vice versa for regulated photosynthetic metabolism were examined in H. annuus. A rapid-response gas exchange system was used to assess changes in carboxylation-related parameters (mesophyll conductance, assimilatory charge and CO2 capacity) and to analyse oscillations in CO2 fixation following transfer to high CO2 concentration as a function of intercellular CO2 concentration and light intensity. Data showed a two- to threefold change in all carboxylation-related parameters during acclimation in either direction. Dynamic regulation of carboxylation, indicated by changes in oscillatory response as a function of CO2 concentration at light saturation, remained unchanged, consistent with concerted regulation of ribulose-1,5-bisphosphate carboxylase-oxygenase during acclimation. However, the light dependency of oscillations changed during acclimation from shade to sun, and the range of oscillation was closely tied to the maximum rate of steady-state photosynthesis at CO2 saturation. These data imply that changes in the light-absorbing and electron transport components of the photosynthetic apparatus underlie the shift in regulatory behaviour during acclimation.

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