Chloroplast structure in normal and pigment‐deficient soybeans grown in continuous red or far‐red light

Abstract

Clark L1, a normal green soybean [Glycine max (L.) Merrill] and Clark y9y9, a backross‐developed isoline exhibiting pigment deficiency, were grown under continuous red (11 W m−2 and far‐red (9 W m−2) light. Chloroplast thylakoids from the unifoliolate leaf (9–10 days old) were isolated and analyzed for pigments, pigment‐protein, membrane polypeptides, electron transport and ultrastructural differences. Chloroplasts of soybean plants grown under far‐red light have decreased chlorophyll a to chlorophyll b ratio, increased light‐harvesting complexes, and grana structure with few stroma‐type thylakoids. Photosystem II/photosystem I ratios (PSII/PSI) are higher in far‐red due to decreased synthesis of PSI reaction center and/or less antenna associated with PSI.