Numerous and highly developed tubular projections from plastids observed in Tobacco epidermal cells.

Tubular projections from plastids (stromules) were observed using a stroma-targeted green fluorescent protein (GFP) fusion protein and a confocal laser scanning microscope. In tobacco (Nicotiana tabacum) epidermal cells, stromules were observed at a high frequency. Some of them were long and connected plastids. Three days after particle bombardment, 80.6+/-6.99% of the transformed cells contained some plastids with more than one stromule, and 40.2+/-7.7% contained at least one pair of plastids connected by stromules. In a few cells, numerous and highly developed stromules covering the whole cell were observed. Stromules were also observed in epidermal cells in each of three other plant species that were tested: rice, dayflower (Commelina communis) and Arabidopsis thaliana. These findings demonstrated that stromules are common structure in plant epidermal cells.