The distribution and ultrastructure of chloroplasts in leaves differing in photosynthetic carbon metabolism. II. Atriplex rosea and Atriplex hastata (Chenopodiaceae)

Abstract

Some aspects of chloroplast development for parenchymatic bundle sheath cells and mesophyll cells of Atriplex rosea leaves are described. The mesophyll chloroplasts begin to degenerate when the bundle sheath chloroplasts have reached a stage of maximum development. These events are related to the changing roles of the two types of chloroplasts in carbon dioxide assimilation. Leaves of Atriplex rosea are similar to those of tropical grasses in leaf anatomy, photosynthetic carbon metabolism, and CO₂ compensation value. Atriplex hastata differs from A. rosea in leaf anatomy and is photosynthetically similar to the temperate grasses. There is a lack of parenchymatic sheath development and the chloroplasts which surround the vascular bundle are ultrastructurally identical with those in the rest of the mesophyll.