Comparative abundance of the large subunit of rubisco in aerial organs of the Japanese morning glory [Ipomoea (Pharbitis) nil] suggests a photosynthetic role for sepals.

摘要

Levels of the large subunit (LSU) of rubisco (ribulose 1,5 bisphosphate carboxylase/oxygenase) were measured in vegetative and floral organs of Pharbitis nil cv. Violet. Identification of the LSU in polypeptides separated by 2-dimensional gel electrophoresis allowed estimation of the relative abundance of this polypeptide in the organs examined. Further quantification was achieved by immunoblotting protein extracts, either alone or in combination with various amounts of extracts from other organs.The amount of LSU decreased in the order leaves > cotyledons > sepals > corollas > androecium, gynoecium. The relative abundance of LSU in sepals (74%) compared to photosynthetically competent organs (leaves (100%) and cotyledons (81%)) suggested that sepals may be photosynthetically competent in supporting development of the other floral organs.