Effect of quick boiling on the formation of chlorophyllide a during extraction. Mature leaves (7th to 9th leaves counting from the bottom of the plant) were collected from 4-week-old wild-type plants that had been sprayed with 100 μM MeJA and kept for 3 days at the same growth conditions. The collected leaves were immersed in pure acetone at room temperature directly or were boiled for 5 and 10 sec respectively before they were immersed in pure acetone, then they were ground with stainless steel beads by vigorous shaking (A and B). Alternatively, pigments were extracted by immersing leaves in pure acetone at 4°C for 12 hours (C and D). A and C, Levels of chlorophyll a and chlorophyllide a per gram fresh weight of leaves. B and D, 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.