Abstract
To characterize photosynthesis in various organs of rice plants, soluble proteins from six different organs were compared by two-dimensional gel electrophoresis. Organs examined were leaf blade (LB), leaf sheath (LS), stem, rachis-branch including rachis (RB), lemma + palea (LP), and root. Either immunoblotting or microsequencing identified 44 spots, which included spots of nine and 14 enzymes involved in the Calvin cycle and carbon/nitrogen metabolism, respectively. Comparison of relative abundances of these spots indicated some unique features in green organs other than LB. The relative abundances of Calvin cycle enzymes in LS differed from those in other green organs, and the level of Rubisco activase was very low in RB. LP and stem shared common features, namely, the abundance of the chloroplastic NADP-ME, the absence of the chloroplastic carbonic anhydrase, and very low levels of the chloroplastic GS2, which could be indications of operation of the C4-like pathway in these organs.
