Effects of day-to-day changes in root temperature on leaf conductance to water vapour and CO2 assimilation rates of Vigna unguiculata L. Walp.

Oecologia ◽  
1982 ◽  
Vol 52 (1) ◽  
pp. 116-120 ◽  
Author(s):  
M. Küppers ◽  
A. E. Hall ◽  
E. -D. Schulze
Oecologia ◽  
1988 ◽  
Vol 75 (1) ◽  
pp. 99-104 ◽  
Author(s):  
B. I. L. Küppers ◽  
M. Küppers ◽  
E. -D. Schulze

2004 ◽  
Vol 31 (12) ◽  
pp. 1195 ◽  
Author(s):  
Steffen M. Noe ◽  
Christoph Giersch

Modelling the diurnal course of photosynthesis in oak leaves (Quercus robur L.) requires appropriate description of the dynamics of leaf photosynthesis of which diurnal variations in leaf conductance and in CO2 assimilation are essential components. We propose and analyse a simple photosynthesis model with three variables: leaf conductance (gs), the CO2 partial pressure inside the leaf (pi), and a pool of Calvin cycle intermediates (aps). The environmental factors light (I) and vapour pressure deficit (VPD) are used to formulate a target function G(I, VPD) from which the actual leaf conductance is calculated. Using this gs value and a CO2 consumption term representing CO2 fixation, a differential equation for pi is derived. Carboxylation corresponds to the sink term of the pi pool and is assumed to be feedback-inhibited by aps. This simple model is shown to produce reasonable to excellent fits to data on the diurnal time courses of photosythesis, pi and gs sampled for oak leaves.


1973 ◽  
Vol 26 (4) ◽  
pp. 705 ◽  
Author(s):  
TF Neales

The CO2 and water vapour fluxes arising from the tops of a plant of A. americana, growing in nutrient solution, were continuously measured at night temperatures of 15, 25, and 36�C, the day temperature being held constant at 25�C.


1985 ◽  
Vol 78 (4) ◽  
pp. 830-834 ◽  
Author(s):  
Suan-Chin Wong ◽  
Ian R. Cowan ◽  
Graham D. Farquhar

1980 ◽  
Vol 7 (4) ◽  
pp. 375 ◽  
Author(s):  
TF Neales ◽  
PJM Sale ◽  
CP Meyer

The effects of variation of day/night temperature regime on the diurnal patterns of CO2 assimilation of pineapple plants were examined using single leaf and field enclosure methods. At day temperatures of 30°C, increasing night temperatures from 20 to 35°C reduced the total assimilation of CO2 per daily light/dark cycle from 6.5 to 1.3 g CO2 m-2 (leaf area) day-1, and also reduced the proportion of total CO2 assimilation that occurred at night from c. 90% to c. 40%. Decreasing day temperatures (30 to 10°C) had little effect on total daily CO2 assimilation in warm (25°C) nights, but reduced it in cooler (15°C) nights. At day temperatures of <152C, CO2 assimilation took place predominantly (60-100%) in the photoperiod. In cool (10°C) days, the normal inverted stomatal rhythm of CAM plants was reversed; leaf conductance was high (c. 1.0 mm s-1) throughout the photoperiod and a large CO2 efflux was observed, lasting c. 2 h, at the beginning of the dark period. Leaf conductance of pineapples, by day and by night, is strongly influenced by ambient temperatures, with cool conditions favouring stomatal opening.


1985 ◽  
Vol 78 (4) ◽  
pp. 821-825 ◽  
Author(s):  
Suan-Chin Wong ◽  
Ian R. Cowan ◽  
Graham D. Farquhar

1985 ◽  
Vol 12 (5) ◽  
pp. 513 ◽  
Author(s):  
M Kuppers ◽  
ED Schulze

An empirical model of CO2 uptake and water loss of leaves is established using steady-state responses of gas exchange to climatic factors as input. From the model the response surface of net CO2 assimilation and leaf conductance to climate can be derived. The model consists of two submodels, one describing the response of CO2 uptake to light and temperature, the other describing the response of leaf conductance to temperature and humidity. Both submodels are joined via the linear relationship between CO2 uptake and leaf conductance at short-term (minutes) variation of irradiance. From the humidity response of leaf conductance and the 'demand function' (Raschke 1979) of CO2 uptake in the mesophyll, the effect of stomata on the diffusion of CO2 between leaf and air is determined. The model is tested by comparing measured and calculated diurnal courses of gas exchange for two plants of Pinus silvestris, differing in photosynthetic capacity due to different levels of magnesium nutrition. Applications and limitations of the model are discussed.


Oecologia ◽  
1981 ◽  
Vol 50 (1) ◽  
pp. 54-61 ◽  
Author(s):  
U. Benecke ◽  
E. -D. Schulze ◽  
R. Matyssek ◽  
W. M. Havranek

1985 ◽  
Vol 78 (4) ◽  
pp. 826-829 ◽  
Author(s):  
Suan-Chin Wong ◽  
Ian R. Cowan ◽  
Graham D. Farquhar

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