26 pale green plants out of 30,000 screened were transplanted but only 11 survived and set seed. Photosynthetic pigments of four of the mutants were further characterized. Total chlorophyll was measured spectrophotometrically in 80% acetone. The absorption spectrum of the most severely affected mutant, MSL-M, is shown in figure 1.1 with an absorption spectrum from a WT leaf extract for comparison. MSL-M had only 20% of the total chlorophyll found in WT leaves and grew more slowly. Photosynthetic pigments were concentrated by partitioning into hexane and separated by TLC on silica gel plates. MSL-M, as well as each other mutant analyzed, contained all of the pigments found in WT leaves (Figure 1.2). This indicated that none of the mutants were deficient in chlorophyll b as has been found in several chlorina mutants (Hirono and Redei 1963). In future classes, students may attempt to correlate growth rate with chlorophyll content using a series of chlorophyll deficient mutants.