Canopy Carbon Assimilation and Crop Radiation-Use Efficiency Dependence on Leaf Nitrogen Content

Author(s):  
T. R. Sinclair
1993 ◽  
Vol 20 (1) ◽  
pp. 40-43 ◽  
Author(s):  
T. R. Sinclair ◽  
J. M. Bennett ◽  
K. J. Boote

Abstract It has been hypothesized that a close correlation exists between specific leaf nitrogen content (SLN, g N m-2 leaf area) and leaf carbon exchange rate (CER), and crop radiation use efficiency (RUE). This association has not been investigated previously in peanut (Arachis hypogaea L.) so the objective of this research was to obtain such data under greenhouse and field conditions. In the greenhouse study differing nitrogen fertilizer treatments for a non-nodulated cultivar resulted in leaves with a wide range of SLN and CER. A strong, positive association between SLN and CER was found. In the field little variation in either SLN or CER was observed through much of the growing season in four commercial cultivars. Consistent with the observation of stability in SLN and CER, RUE based on total, intercepted solar radiation was found to be constant at 1.00 g MJ-1 through the growing season. However, the observed RUE was 29% greater than a theoretical RUE calculated assuming a uniform distribution of SLN in the canopy. One possibility is that RUE of peanuts may be enhanced by a nonuniform SLN distribution within its leaf canopy. In any event, the results of both the greenhouse and field tests showed that peanut CO2 assimilation is closely linked to leaf SLN.


Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 101-110 ◽  
Author(s):  
S. Sridhara ◽  
T.G. Prasad

SUMMARYA field experiment was conducted at Gandhi Krishi Vignana Kendra, University of Agricultural Sciences, Bangalore to study the effect of irrigation regimens on the biomass accumulation, canopy development, light interception and radiation use efficiency of sunflower. The treatments includes irrigating the plants at 0.4, 0.6, 0.8 and 1.0 cumulative pan evaporation. The results indicated that the aboveground biomass, canopy development, radiation interception and radiation use efficiency were influenced favorably by the irrigation regimens. Irrespective of the irrigation regimen, the radiation use efficiency of sunflower increased from 15 DAS to 75 DAS and then tended to decline. The decrease in RUE after anthesis is coupled with decrease in leaf nitrogen content. In general the RUE of sunflower ranged from 0.49 g MJ-1 to 1.84 g MJ-1 at different growth stages. The light transmission within the canopy increased exponentially with plant height and the canopy extension coefficient is found to be 0.8.


1995 ◽  
Vol 41 (2) ◽  
pp. 65-77 ◽  
Author(s):  
A.J. Hall ◽  
D.J. Connor ◽  
V.O. Sadras

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