Early studies indicated that phytochromes mediate light-induced carotenoid biosynthesis in tomato by conducting red and far-red light during ripening (Khudairi & Arboleda, 1971; Thomas & Jen, 1975). Alba and co-workers (2000) reported that red light treatments (six 40W Gro-lux lamps) increased lycopene accumulation 2.3-fold in tomatoes and that red light-induced lycopene accumulation was reversible by far-red light treatment. They concluded that the accumulation of lycopene was under the control of fruit-localised phytochromes. Other studies have shown that red light treatment increases the carotenoid content and red colour of tomatoes, with varying effects on tomato firmness (Lee, Bunn,
Han, & Christenbury, 1997).