Thompson, A.E. and J.P. McCollum.
Immature fruits on plants homozygous for the mutant gene albescent (ab) are usually white or pale yellow in color. Areas containing chlorophyll on stems and leaves are also greatly restricted in size. Fruit size is restricted and rarely exceed 1 1/4 inches in diameter. Even though the albescent plants are genetically red fruited, very little carotenoid pigment is produced. A hexane extract of pigment from ripe fruits gave 0.98 mgms./100 gms. fresh weight of total pigments and 0.176 mgms./100 gms. beta carotene. Readings of the absorption spectrum of the total hexane extract indicated a relatively high content of colorless carotenoids. The absorption spectra maxima in millimicrons were circa 367, 400, 425, 444, 470 and 502.
The presence of colorless carotenoids perhaps would indicate that a sufficient quantity of energy is lacking to carry the biosynthetic reactions to completion.
Of further interest is the observation that normal appearing, redpigmented fruits were borne on scions of normal green plants grafted to the albescent stock plants. The quantity and quality of pigments present were not analyzed however.
It would appear that farther study of pigment production of this mutant might lead to a clearer understanding of the biosynthesis of carotenoid pigments in the tomato fruit.