Absorbance Changes at 520 nm Induced by 700 nm Light in Shortly Preilluminated Etiolated Bean Leaves
Etioplasts isolated from 14 day-old etiolated bean seedlings can photoreduce NADP+ already after three minutes of illumination (1). Such an early PSI activity asks the question of the presence of P700 at a greening stage when the mean green pigment is chlorophyllide. Jouy (2) discovered that 30s-red preilluminated etiolated leaves exhibit a light-induced absorbance increase between 500 and 550 nm. In green leaves, it is known that absorbance changes in that region reflect the photochemistry of reaction centers (3). We report here the efficiency of red and far-red light to produce this change in order to detect a photoactive long-wavelength absorbing pigment — similar to P700 — in etiolated and shortly greened leaves.
KeywordsGreen Leaf Absorbance Change Actinic Light Green Pigment Greening Stage
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