To investigate the development of plastids in various leaf tissues of a NAD-MEtype C4 plant, Amaranthus patulus Bertoloni, structural changes of etioplasts undercontinuous illumination were observed by means of an electron microscope. Before theillumination, all etioplasts in epidermal cells including guard cells, mesophyll cells, bundlesheath cells, and vascular parenchymatous cells were small and spherical in shape, andcontained prolamellar bodies with extending single-thylakoids. After the illumination, theplastids elongated, and the disorganization of prolamellar bodies and the formation ofprimary grana occurred at first in epidermal plastids, secondary in mesophyll plastids,then in bundle sheath plastids, and finally in vascular parenchymatous plastids. Thisdifference of start for plastid morphogenesis among leaf tissues may be reflected simply bythose anatomical arrangement for light exposure. The function of peripheral reticulumfound in mesophyll and bundle sheath chloroplasts and the crystalline iclusion in epidermalplastids was also discussed
