Identification of a Triterpenoid Saponin in Etiolated Pea Shoots as Phytochrome Killer

Abstract

Phytochrome killer, a substance which instantaneously causes in vitro spectral denaturation of phytochrome, was isolated in the pure state from the methanol extract of etiolated pea shoots by Sephadex G-25, charcoal and silica gel chromatographies. Chemical and spectrometric (nuclear magnetic resonance, mass and infra-red) analyses disclosed that this substance was identical with soyasaponin I, a triterpenoid saponin. Most of the phytochrome killer activity in the methanol extract was ascribable to soyasaponin I. The content of this saponin was 61 μg/g fr wt in the etiolated epicotyl tissue and 27 μg/g fr wt in the green epicotyl tissue.