The mouse ear cress Arabidopsis thaliana is a member of the Brassicaeae that lends itself well to genetic study in that it has only a small quantity of DNA. The plant itself has little commercial value aside from that as a research tool, and it has no aesthetic horticultural value at all. It is a small plant that can be grown by the hundreds in cells on a laboratory bench, and its small quantity of DNA makes it useful in identifying genes of other organisms (Wheeler, 1994).

  Normal flower color varies between solid white petals to green petals only tinged with white. Manipulation of flower color is of interest not because of any potential ornamental value, but because of the mechanisms of gene expression in the visible appearance of the yellow pigment anthocyanin.

  In like manner, information regarding cold tolerance and the biochemical changes that occur within the plant in response to cold are not of interest primarily for culture of the plant itself except as it applies to cultural conditions that need to be maintained for optimum life cycle completion time. Rather, Arabidopsis’ response to cold stress is of interest because facts learned from it can be applied to investigations in human systems (Stockinger, Gilmour and Thomashow, 1997). This investigation seeks to determine if enough anthocyanin can be concentrated in petal cells so that they express a visible yellow color, and if cold stress has any effect on visible levels of anthocyanin concentrations in petal cells.

  Arabidopsis naturally contains anthocyanin, and Lloyd, Walbot and Davis (1992) were able to cause anthocyanin "pathway-specific transcriptional activators R and C1 from the monocot maize were expressed in two dicots, Arabidopsis thaliana and Nicotiana tabacum. Expression of R caused augmented anthocyanin pigmentation in both plant species and augmented trichome (hair) production in Arabidopsis" (p. 1773), but C1 had no effect alone. Expression of both in Arabidopsis resulted in expression of anthocyanins in tissues that normally contain none, such as root, petal and stamen tissues. In more recent research, Walker, Davison, Bolognesi-Winfield, James, Srinivasean, Blundell, Esch, Marks and Gray (1999), the researchers isolated by positional cloning the transparent testa glabra1 (TTG1) locus they had previously determined as regulating development of anthocyanins in Arabidopsis.