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Articles 1 - 5 of 5

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Weedy Adaptation In Setaria Spp. V. Effects Of Gaseous Environment On Giant Foxtail (Setaria Faberii) (Poaceae) Seed Germination, Jack H. Dekker, Mark S. Hargrove Mar 2002

Weedy Adaptation In Setaria Spp. V. Effects Of Gaseous Environment On Giant Foxtail (Setaria Faberii) (Poaceae) Seed Germination, Jack H. Dekker, Mark S. Hargrove

Agronomy Publications

The effects that naturally occurring gases (oxygen, nitrogen, carbon monoxide) may cause in dormant giant foxtail (Setaria faberii) seed germination under favorable temperature and moisture conditions were investigated. The germination responses to gas mixtures supported the hypothesis that S. faberii germination behavior is regulated by the amount of oxygen taken into hydrated seed over time. Setaria faberii seed germination was markedly affected by O2 concentration (in N2) above and below that of air (20% O2): the largest increase in germination (from 37 to 60%) occurred between 20–25% O2; between 0–10% O2, germination increased ...


Identification And Characterization Of Proteins Expressed In The Nectar Of Ornamental Tobacco , Clay Jeremy Carter Jan 2002

Identification And Characterization Of Proteins Expressed In The Nectar Of Ornamental Tobacco , Clay Jeremy Carter

Retrospective Theses and Dissertations

A small set of proteins, termed Nectarins, are secreted into the nectar of ornamental tobacco (Nicotiana langsdorffii x Nicotiana sanderae). The most highly expressed protein, Nectarin I (29 kD monomer), was originally identified as a germin-like protein (GLP) of unknown function. This remarkably stable protein was later shown to possess manganese dependent superoxide dismutase activity. Hydrogen peroxide, the product of SOD activity, was found to accumulate in nectar at levels up to 4 mM. The promoter (1.2 kb) of the Nectarin I gene was fused to the reporter gene chloramphenicol acetyl transferase (CAT) and shown to be expressed in ...


Enzyme Activities In Soils As Affected By Management Practices , Mine Ekenler Jan 2002

Enzyme Activities In Soils As Affected By Management Practices , Mine Ekenler

Retrospective Theses and Dissertations

Studies were undertaken to investigate the long-term effects of lime application and tillage systems (no-till, ridge-till, and chisel plow) on soil microbial biomass C (Cmic) and N (Nmic) and the activities of glycosidases (alpha- and beta-glucosidases, alpha- and beta-galactosidases and beta-glucosaminidase); phosphatases (acid and alkaline phosphatases and phosphodiesterase); amidohydrolases (L-asparaginase, L-glutaminase, amidase, urease, and L-aspartase); and arylamidase at their optimal pH values. With the exception of acid phosphatase, which was significantly but negatively correlated, all other enzyme activities were significantly and positively correlated with soil pH values at four sites in Iowa. Delta activity/Delta pH values showed that among ...


Backcross Introgression And Two-Stage Testing For Conversion Of Improved Tropical Germplasm To Temperate Environments , Freeman Callaway Whitehead Jan 2002

Backcross Introgression And Two-Stage Testing For Conversion Of Improved Tropical Germplasm To Temperate Environments , Freeman Callaway Whitehead

Retrospective Theses and Dissertations

The use of exotic maize (Zea mays L.) germplasm, particularly of tropical and subtropical adaptation, has been suggested to increase genetic variability and grain yield of maize breeding material in temperate environments. Lack of adaptation to temperate areas and photoperiod sensitivity may mask desirable traits and reduce breeding progress. The objectives of this study included two-stage evaluation and selection of segregating families in the central U.S. Corn Belt derived from the backcross introgression of previously improved tropical CIMMYT germplasm into adapted, elite U.S. Corn Belt germplasm. The U.S. Corn Belt heterotic patterns of Stiff Stalk and non-Stiff ...


Molecular Marker Analysis Of Seed Size In Soybean , Joseph Andrew Hoeck Jan 2002

Molecular Marker Analysis Of Seed Size In Soybean , Joseph Andrew Hoeck

Retrospective Theses and Dissertations

Seed size is an important attribute of soybean [Glycine max (L.) Merr.] for some food uses. The objectives of this study were to identify markers associated with quantitative trait loci for seed size (SSQTL), determine the influence of the environment on expression of the marker-SSQTL associations, and compare the efficiency of phenotypic selection and marker-assisted selection for the trait. Three small-seeded lines were crossed to a line or cultivar with normal seed size to form three two-parent populations. The parents of the populations were screened with 178 simple sequence repeat (SSR) markers to identify polymorphism. Population 1 (Pop 1) had ...