The response of plant species to future atmospheric carbon dioxide concentrations [CO(2)] has been determined for hundreds of crop and tree species. However, no data are currently available regarding the response of invasive weedy species to past or future atmospheric [CO(2)]. In the current study, the growth of six species which are widely recognized as among the most invasive weeds in the con...

In an effort to design a bioassay to screen for biocontrol pathogens and their toxins, procedures were developed to produce calli of yellow starthistle (YST), Centaurea solstitialis (Asteraceae), on solid and liquid media. Three Murashige and Skoog (MS) media with different hormone additives were compared for their effects on the growth of the YST calli. The most effective medium was made of MS...

Yellow starthistle (YST) (Centaurea solstitialis) is an invasive weed in the USA and a target of classical biological control. However, the precise geographical origin(s) of YST in the USA is not known. This study was conducted to learn whether the origin(s) of YST in California, USA could be determined on the basis of digital image analysis (DIA) of YST reactions to isolates of the rust Puccin...