Chloroplast Biogenesis 34

Abstract

The fluorescence emission and excitation properties of protochlorophyll in etiolated cucumber (Cucumis sativus L.) cotyledons and primary bean (var. Red Kidney) leaves were characterized at 77 K. Contrary to previous studies, it appears that the short-wavelength protochlorophyll emission band consists of four fluorescent components, instead of only one nonphototransformable protochlorophyll. It was demonstrated that etiolated cucumber cotyledons synthesize and accumulate nontransformable protochlorophyll (E₄₄₀, F₆₃₀) as well as short-wavelength phototransformable protochlorophyll (E₄₃₃, F₆₃₃), (E₄₄₄, F₆₃₆), and (E₄₄₅, F₆₄₀). Long-wavelength phototransformable protochlorophyll (E₄₅₀, F₆₅₇) is also formed. In this context, E refers to the Soret excitation maxima and F refers to the red emission maxima of the protochlorophylls.