CHLOROPHYLL‐DEFICIENT CELL LINES WHICH ARE GENETICALLY UNCHARACTERIZED CAN BE INAPPROPRIATE FOR USE AS PHENOTYPIC MARKERS IN DEVELOPMENTAL STUDIES

Abstract

Periclinal chloroplast chimeras are genetic mosaics which possess shoot apices composed of one or more chlorophyll‐deficient histogens and can exist as a series of arrangements of normal and mutant layers (A‐B‐B, A‐B‐A, etc.). Three periclinal chimeral cultivars of Sansevieria trifasciata L., each of which possesses normal green cell layer(s) but a genetically different chlorophyll‐deficient cell layer(s), were utilized to study the effect of genotype on the ability of the cell layers of leaf cuttings and of cultured leaf tissue to regenerate shoots. The epidermis and LI derivatives were apparently incapable of shoot regeneration via leaf cutting, yet in two cultivars produced some shoots in vitro. In two of the cultivars, the chlorophyll‐deficient cells never produced shoots. In the third, the capability of chlorophyll‐deficient cell layers to produce shoots was less in vitro than in vivo, indicating that when determining morphogenic potential, direct comparisons between in vitro and in vivo systems may not be valid. Results also demonstrate that because genetically different albino cell layers can differ in their morphogenic response, utilizing a series of periclinal chimeras is useful only if the series is composed of the same two genotypes.