Time course of chlorophyllide a formation during pigment extraction. Chlorophyll was extracted by immersing leaves in pure acetone as described in the “Time-course experiments” subsection of the Methods section. A. Levels of chlorophyll a and chlorophyllide a per gram fresh weight of leaves. B. Chlorophyllide a levels in sample extracts expressed as the ratio of chlorophyllide a to the sum of chlorophyll a and chlorophyllide a. Chl a, chlorophyll a. Chlide a, chlorophyllide a. Error bars indicate standard deviations. Sample size, n = 3. n.d. = not detected.