PROTOCHLOROPHYLLIDE FORMS IN NON-GREENING EPICOTYLS OF DARK-GROWN PEA(PISUM-SATIVUM)

Low-temperature fluorescence emission spectra of 6.5-day-old dark-grow n epicotyls of pea (Pisum sativum) revealed the presence of protochlor ophyll(ide). The upper part of the epicotyl contained 30% of the proto chlorophyll(ide) content per fresh weight found in pea leaves, whereas the lower part contained 3%. Three discrete spectral forms of protoch lorophyll(ide) were clearly distinguished after Gaussian deconvolution of fluorescence excitation and emission spectra. Adding the satellite bands of the Qy((0-0)) transitions (the emission vibrational (Emv) ba nds with correlated amplitudes) gave the following delineation: Ex439- Em629-Emv684, Ex447-Em636-Emv700 and Ex456-Em650-Emv728. Sodium dodecy l sulphate polyacrylamide gel electrophoresis (SDS-PAGE) followed by i mmunodetection of whole tissue extracts of the epicotyl indicated the presence of NADPH-protochlorophyllide oxidoreductase (EC 1.3.1.33). El ectron micrographs showed prolamellar bodies in at most 11% of the pla stid profiles of the epicotyl cells. These prolamellar bodies were sma ller, and many of them showed less regular structure than those of the leaves. Taken together, the results indicate that the protochlorophyl l(ide) in epicotyls is arranged in a different way than in leaves.