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Carbon Dioxide Assimilation Efficiency Of Maize Leaves Under Nitrogen Stress At Different Stages Of Plant Development, John Settimi, Jerry Maranville
Carbon Dioxide Assimilation Efficiency Of Maize Leaves Under Nitrogen Stress At Different Stages Of Plant Development, John Settimi, Jerry Maranville
John R. Settimi
Sub-optimal nitrogen (N) affects the N-rich carbon dioxide (CO2) assimilation enzymes which can limit maize (Zea mays) production. The status of the carboxylation system is closely correlated to the Assimilation Efficiency Index (AEI) which is the initial slope of the CO2 assimilation rate versus intercellular leaf CO2 concentrations. Experiments were undertaken to ascertain the effect of soil N nutrition on the AEI, determine genotypic variability for AEI under N-deficiency, determine how leaf and plant development affect treatment differences, and examine correlations between the AEI and plant development. Studies were conducted in the field and greenhouse on five maize genotypes on …
Photoperiod And Planting Date Effects On The Spatial Distribution Of Branch Development In Soybean, John Settimi, James Board
Photoperiod And Planting Date Effects On The Spatial Distribution Of Branch Development In Soybean, John Settimi, James Board
John R. Settimi
Reduced branch development in late-planted soybean [Glycine max (L.) Merr.] is a cause of yield reductions in the southeastern USA. To determine the effects of photoperiod and planting date on the spatial distribution of branches, photoperiod simulations of an optimal (24 May) and a nonoptimal late planting date (24 June) at Baton Rouge, LA (30°N Lat), were imposed on ‘Centennial’ soybean in growth chambers. In a field study, ‘Lee 74’ was planted at optimal (mid-May) and nonoptimal (early July) planting dates in 1984 and 1985 at Baton Rouge, LA, on an Olivier silt loam (fine-silty, mixed thermic Aquic Fragiudalf) soil. …