Pigmentation in Transgenic Plants - Plants are widely used for ornamental purposes, so it is not surprising that considerable attempts have been made to develop varieties having flowers with new colour, shape and growth properties can be engineered.

Pigmentation in flowers is mainly due to three classes of compounds, the flavonoids, the carotenoids and the betalains. Of these, the flavonoids are the best characterized with much information now available concerning their chemistry, biochemistry and molecular genetics.

It is expected that increased production of the encoded enzyme might produce flowers with a deeper purple colour. But white coloured flowers where produced due to co suppression. Co-suppression now has been demonstrated in numerous other systems.

It does not appear to be a dosage effect resulting from competition for transcription factors. Nor is it a result of a system that detects specific duplicate plant genes. Rather it appears to be the result of a homology dependent interaction between homologous sequences.