Plastid Tubules in the Sporogenous Lineage of the Moss Timmiella barbuloides (Bryophyta): An Ultrastructural Study

Tubular inclusions are ubiquitous in the sporogenous plastidsof the moss Timmiella barbuloides (Brid.) Moenk. They have anouter diameter of 26–40 nm and a central lumen of 10–15nm, and occur either singly or in groups of up to 15 parallelelements in the peripheral stroma. The tubules are associatedwith the central isthmus in dividing plastids but lie closeto the extremities during the growth phase. These positionalchanges suggest roles in plastid division, growth and the maintenanceof shape. Bryophytes, mosses, Timmiella barbuloides, sporogenous cell lineage, plastid tubules, ultrastructure