Carotenoids have been shown to be important both nutritionally and medicinally. Carotenoid accumulation was compared during growth and storage of four carrot genotypes: YY y1y1y2y2RPRP, yyY1 Y1Y2Y2 RPRP, YY Y1 Y1Y2Y2 RPRP, and rprp. These genotypes exhibit orange, yellow, white, and pale-orange roots respectively. The orange and pale-orange genotypes are near-isogenic for rp, a gene that reduces total carotenoid content by 93%. Genotypes were grown in replicated field plots during 1996 and stored for 8 months at 4°C. Samples of root tissue were removed at 7-day intervals during vegetative growth and 4-week intervals during the postharvest period. Total carotenoid content were quantified using HPLC and spectrophotometric analyses. Increases in carotenoid content of 119% and 79% in rprp and YY y1y1y2y2RPRP and decreases of 6% and 64% in YYY1 Y1Y2Y2RPRP and yyY1 Y1Y2Y2RPRP, respectively, were measured between 62 and 100 days after planting. At 100 days after planting, YY y1y1y2y2RPRP exhibited 10-fold greater carotenoid content than rprp. Carotenoid content in yyY1 Y1Y2Y2RPRP and YY y1y1y2y2RPRP increased during the first 28 days of storage and decreased subsequently. Meanwhile, rprp began to decrease in carotenoid content at day 14 of storage. HPLC analysis at l = 445 nm revealed two large unique peaks in rprp with elution times of 27 and 28.7 minutes that were of lesser abundance in YY y1y1y2y2RPRP, suggesting that the rate of β- and α-carotene accumulation is not the only difference between YY y1y1y2y2RPRP and rprp.
If the inline PDF is not rendering correctly, you can download the PDF file here.