scholarly journals Difference in single leaf photosynthesis between old and new rice varieties. I. Single-leaf photosynthesis and its dependence on stomatal conductance.

1990 ◽  
Vol 59 (2) ◽  
pp. 283-292 ◽  
Author(s):  
Eiki KURODA ◽  
Atsuhiko KUMURA
Keyword(s):  
Stomatal Conductance ◽  
Leaf Photosynthesis ◽  
Rice Varieties ◽  
Single Leaf

scholarly journals Irrigated Soybean Leaf Photosynthesis in the Humid Subtropical Midsouth

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
H. Arnold Bruns
Keyword(s):  
Stomatal Conductance ◽  
Growth Stage ◽  
Cultivar Differences ◽  
Photon Flux ◽  
Growth Stages ◽  
Base Temperature ◽  
Leaf Photosynthesis ◽  
Photosynthetic Photon Flux ◽  
Single Leaf ◽  
Soybean Leaf

Photosynthesis (CER (μmol CO2mleaf area-2 s−1)), stomatal conductance (gsw), and intercellular [CO2] (Ci) of soybean (Glycine maxL. Merr.) grown using the early soybean production system (ESPS) of the midsouth were determined. Three irrigated cultivars were grown using ESPS on Bosket (Mollic Hapludalfs) and Dundee (Typic Endoaqualf) soils in 2011 and 2012 at Stoneville, MS. Single leaf CER,gsw, andCiwere determined at growth stages R3, R4, and R5 using decreasing photosynthetic photon flux densities (PPFD,μmol m−2 s−1) beginning at 2000 PPFD and decreasing by 250 PPFD increments to 250 PPFD. Photosynthesis changes fit a quadratic polynomial for all fixed variables and range from ~6.0 and 9.0 CER at 250 PPFD and ~22.0 to 28.0 CER at 2000 PPFD. No cultivar differences in CER,gsw, orCiwere noted at any growth stage or site either year. In 2012, CER,gsw, andCiwere lower when measured at R5 than the two previous growth stages, which was not observed in 2011. The R5 sampling in 2012 had accumulated 39 to 70 more growing degree units at 10°C base temperature (GDU 10’s) than in 2011 and were likely more mature. Increased soybean yields from ESPS appear not to result from higher leaf CER.

Modelling Canopy Production. II. From Single-Leaf Photosynthesis Parameters to Daily Canopy Photosynthesis

1995 ◽  
Vol 22 (4) ◽  
pp. 603 ◽  
Author(s):  
PJ Sands
Keyword(s):  
Simple Algorithm ◽  
Light Response ◽  
Daily Maximum ◽  
Canopy Photosynthesis ◽  
Leaf Photosynthesis ◽  
Daily Production ◽  
Area Index ◽  
Single Leaf ◽  
Diurnal Temperature Variation ◽  
Analytical Expressions

This paper presents a simple algorithm for calculating daily canopy photosynthesis given parameters of the single-leaf light response, the canopy extinction coefficient, canopy leaf area index, daylength, daily solar irradiance and daily maximum and minimum temperatures. Analytical expressions are derived for total daily production by a canopy of leaves whose light response is either a rectangular hyperbola or a Blackman response. An expression which gives an excellent approximation to canopy photosynthesis for an arbitrary hyperbolic light response is then derived. These expressions assume photosynthetically active radiation (PAR) within the canopy follows Beer's law, light-saturated photosynthetic rate at any point in the canopy is proportional to the ratio of local PAR to full-sun PAR, diurnal variation of PAR is sinusoidal, and parameters of the single-leaf photosynthetic light response do not vary diurnally. It is shown how these expressions can be used to accommodate diurnal temperature variation of photosynthesis in a simple manner. The accuracy of the approximation to the basic integral of leaf photosynthesis over the canopy and over time is illustrated by applying the algorithm to compute the seasonal variation of daily canopy photosynthesis and comparing these data with corresponding values obtained by numerical integration.

scholarly journals Orange Rust Effects on Leaf Photosynthesis and Related Characters of Sugarcane

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 640-647 ◽  
Author(s):  
Duli Zhao ◽  
Neil C. Glynn ◽  
Barry Glaz ◽  
Jack C. Comstock ◽  
Sushma Sood
Keyword(s):  
Stomatal Conductance ◽  
Quantum Yield ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Carbon Fixation ◽  
Dark Respiration ◽  
Western Hemisphere ◽  
Maximum Quantum Yield ◽  
Leaf Photosynthesis

Orange rust of sugarcane (Saccharum spp. hybrids), caused by Puccinia kuehnii, is a relatively new disease in the Western Hemisphere that substantially reduces yields in susceptible sugarcane genotypes. The objective of this study was to determine the physiological mechanisms of orange rust–induced reductions in sugarcane growth and yield by quantifying effects of the disease on leaf SPAD index (an indication of leaf chlorophyll content), net photosynthetic rate, dark respiration, maximum quantum yield of CO2 assimilation, carbon fixation efficiency, and the relationships between these leaf photosynthetic components and rust disease ratings. Plants growing in pots were inoculated with the orange rust pathogen using a leaf whorl inoculation method. A disease rating was assigned using a scale from 0 to 4 with intervals of 0.5. At disease ratings ≥2, the rust-infected leaf portion of inoculated plants showed significant reductions in SPAD index, maximum quantum yield, carbon fixation efficiency, stomatal conductance, leaf transpiration rate, and net photosynthetic rate; but the rusted portion of the infected leaves had increased intercellular CO2 concentration and leaf dark respiration rate. Although leaf SPAD index, photosynthetic rate, stomatal conductance, and transpiration rate at the rust-infected portion decreased linearly with increased rust rating, the effect of orange rust on photosynthetic rate was much greater than that on stomatal conductance and transpiration. Unlike earlier reports on other crops, reduction in leaf photosynthesis by orange rust under low light was greater than that under high light conditions. These results help improve the understanding of orange rust etiology and physiological bases of sugarcane yield loss caused by orange rust.

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