Biological characterization of a southeast Kansas mining site

Soils from a heavy metal contaminated southeast Kansas mining site were characterized for microbial resistance to zinc, cadmium, and lead. Plant availability indices (DTPA-extractable) for zinc were very high in the waste material (610 Μg g^?1), while levels of lead and cadmium were more moderate, 45 and 4.3 Μg g ^?1, respectively. Soil contamination decreased with distance from the mine tailings or ‘chat’. In the rhizosphere, bacterial resistance to zinc and cadmium increased as the DTPA-extractable plant availability indices increased. Mycorrhizal root colonization was not affected by the heavy metal concentration in the soil. The established vegetation in the contaminated area included warm- and cool-season grasses as well as forbs and sedges.     

Evaluation of Biodegradability and Biodegradation Kinetics for Anionic, Nonionic, and Amphoteric Surfactants

The biodegradation kinetics of anionic (sodium laureth sulfate – SLES), amphoteric (disodium cocoamphodiacetate – DSCADA), and nonionic surfactants (polyalcohol ethoxylate – PAE) were assessed in this laboratory study. Similar degradation behavior was observed for all surfactants with only a fraction of the parent compound readily biodegradable. Biodegradation, as estimated by COD removal, was initially (i.e., within 24 h) rapid, however only 40–70% of the surfactant molecules were readily biodegradable. Intrinsic kinetic parameters were successfully quantified for the readily biodegradable component of the surfactant. Inhibition was not observed and microbial kinetics of SLES, DSCADA, and PAE degradation fit the Monod model well. Average μ-S curves were generated for each surfactant. Based on these results, complete degradation of the target surfactants using biological waste treatment would be limited.     

Comparison of TAF46 and Zhong 5 resistances to barley yellow dwarf virus from Thinopyrum intermedium in wheat

Barley yellow dwarf virus (BYDV) is one of the most important plant viruses in the world. Two sources of resistance to BYDV derived from Thinopyrum intermedium were compared in wheat backgrounds. A source of resistance was confirmed in the partial amphiploid TAF46, the group 7 addition line L1, and translocation TC14. The other source of resistance derives from the partial amphiploid Zhong 5 and is present in the group 2 addition line Z6. Six ditelosomic addition lines have been derived from Z6. The resistance of genotypes derived from Zhong 5 is more effective at reducing virus multiplication throughout plant growth than that of genotypes derived from TAF46. The translocation line TC14, derived from TAF46 showed 30% plants escaping virus infection whereas all plants derived from Zhong 5 were infected. This suggests that the two sources of resistance are associated with differing mechanisms of resistance. Methods to better understand the genetic control and the mechanisms of these two resistances are suggested. The pyramiding of different sources of resistance to construct durable resistance is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Self-incompatibility as a pollination control mechanism for spring oilseed rape,Brassica napus L.

Summary Self-incompatibility was shown to be an effective method of pollination control in spring rapeseed (B. napus L. ssp. oleifera (Metzg.)) by comparing the yield of a Westar-Topas syn-1 produced by crossing two SI lines with the yield of the corresponding syn-1 produced by hand pollination. Although the trial showed high-parent heterosis in the syn-1s, there was insufficient replication to determine the level of heterosis.Abbreviations SI self-incompatible - SC self-compatible     

Heritability of Phytoremediation Potential for the Alfalfa CultivarRiley in Petroleum Contaminated Soil

Petroleum contamination poses a significant threat to environmental ecosystems world-wide. Phytoremediation can be used to enhance degradation of petroleum contaminants in soil. However, selection of plants for phytoremediation has proven to be complicated. This research examines the heritability of the alfalfa cultivar Riley for phytoremediation based on parental total petroleum hydrocarbon (TPH) degradation after twelve months of growth. Traits other than degradation potential, such as root and shoot yield, height, and maturity, were examined for use as selection traits. Riley showed moderate to low heritability that suggests the possibility of breeding for phytoremediation efficiency. In addition, root and shoot yield were found to correlate to TPH degradation. Crosses in which the female parent was typically associated with low TPH dissipation yielded progeny that were high efficiency TPH degraders.