Chlorophyll Biosynthetic Capacity and Xanthophyll Cycle of a White-Green Variegated Ficus microcarpa Cv. Milky Stripe

The white sector in the variegated leaves are studied by the variegated mutant lines, but the photosynthetic properties in the leaves of natural plant were less been examined. In present study, we analyzed the chlorophyll biosynthetic capacity and xanthophyll cycle components in the green and white sectors of variegated leaves of milky stripe fig (Ficus microcarpa cv. milky stripe). The white sector had approximately 2.2 % as much chlorophyll and 9.5 % as much carotenoid as does the green sector, but the ratio of carotenoid to chlorophyll in the white sector was 5.3- fold higher than that in the green sector. HPLC analysis demonstrated that, excepting neoxanthin, all other identified carotenoids were presented in large quantities in the green sector than in the white sector. The rate of degradation of protoporphyrin IX (PPIX), magnesium protoporphyrin IX (MGPP), and protochlorophyllide (Pchlide) in the white sector was higher than that in the green sector. Δ-Aminolevulinic acid (ALA)-supplementation test indicates that the chlorophyll biosynthesis between ALA and Pchlide was partially impaired in the white sector, but is remarkably impaired in the steps after Pchlide. This study revealed the deficient process of photosynthesis and the importance of xanthophyll cycle in the white sector of natural leaves.