scholarly journals Relationships between CO2 Exchange Rates and Activities of Pyruvate,Pi Dikinase and Ribulose Bisphosphate Carboxylase, Chlorophyll Concentration, and Cell Volume in Maize Leaves

1985 ◽  
Vol 77 (3) ◽  
pp. 612-616 ◽  
Author(s):  
Gianni R. Baer ◽  
Larry E. Schrader
Keyword(s):  
Exchange Rates ◽  
Cell Volume ◽  
Chlorophyll Concentration ◽  
Co2 Exchange ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Maize Leaves

Characteristics of pea leaves and their relationships to photosynthetic CO2 exchange in the field

1983 ◽  
Vol 61 (12) ◽  
pp. 3283-3292 ◽  
Author(s):  
J. D. Mahon ◽  
S. L. A. Hobbs ◽  
S. O. Salminen
Keyword(s):  
Direct Determination ◽  
Stomatal Resistance ◽  
Co2 Exchange ◽  
Photosynthetic Performance ◽  
Time Of Day ◽  
Ribulose Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate ◽  
Carboxylase Activity ◽  
Single Experiment ◽  
Bisphosphate Carboxylase

Photosynthetic CO2 exchange rate (CER) was determined in attached leaflets of field-grown peas (Pisum sativum L.) Three populations of genotypes were studied in different field locations and years. In 1 year, CER, leaf characteristics, and meteorological factors were measured in parallel at different times of the day and season. Differences in CER across environments or time of day were related to differences in stomatal resistance; however, changes during the season, which might be of environmental or developmental origin, were not. Genotype ranking for CER was largely independent of measuring time, field location, and year. None of the leaf characters which have been suggested as simple assays for photosynthetic ability (specific leaf weight, chlorophyll content, stomatal resistance) was consistently related to CER over several tests. In the single experiment in which they were determined, ribulose bisphosphate carboxylase activity, leaf soluble protein content, and the difference in CER at 2 and 20 kPa O2 were also not correlated with CER. The O2 effect expressed as a percentage of CER at 2 kPa O2 and the slope of the light response above 50 nE cm−2 s−1 were significantly correlated to CER, but neither is suitable for predicting CER in different genotypes. A significant multiple regression of CER on stomatal resistance, total chlorophyll, and ribulose bisphosphate carboxylase activity suggests that the genetic control of CER may involve several characters. In this case, direct determination of CO2 exchange may be the easiest and most reliable way of assessing genetic differences in photosynthetic performance.

scholarly journals SCARECROW gene function is required for photosynthetic development in maize

2020 ◽  
Author(s):  
Thomas E. Hughes ◽  
Jane A. Langdale
Keyword(s):  
Leaf Anatomy ◽  
Pyruvate Carboxylase ◽  
Chloroplast Development ◽  
Photosynthetic Capacity ◽  
Ribulose Bisphosphate Carboxylase ◽  
Wild Type ◽  
Ribulose Bisphosphate ◽  
Bisphosphate Carboxylase ◽  
Maize Leaves ◽  
Ribulose Bisphosphate Carboxylase Oxygenase

AbstractC4 photosynthesis in grasses relies on a specialized leaf anatomy. In maize, this ‘Kranz’ leaf anatomy is patterned in part by the duplicated SCARECROW (SCR) genes ZmSCR1 and ZmSCR1h. Here we show that in addition to patterning defects, chlorophyll content and levels of transcripts encoding Golden2-like regulators of chloroplast development are significantly lower in Zmscr1;Zmscr1h mutants than in wild-type. These perturbations are not associated with changes in chloroplast number, size or ultrastructure. However, the maximum rates of carboxylation by ribulose bisphosphate carboxylase/oxygenase (RuBisCO, Vcmax) and phosphoenolpyruvate carboxylase (PEPC, Vpmax) are both reduced, leading to perturbed plant growth. The CO2 compensation point and 13C‰ of Zmscr1;Zmscr1h plants are both normal, indicating that a canonical C4 cycle is operating, albeit at reduced overall capacity. Taken together, our results reveal that the maize SCR genes, either directly or indirectly, play a role in photosynthetic development.Significance statementSCARECROW (SCR) is one of the best studied plant developmental regulators, however, its role in downstream plant physiology is less well-understood. Here, we have demonstrated that SCR is required to establish and/or maintain photosynthetic capacity in maize leaves.

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