Stromules: Dynamic Tubular Extensions of Plastids in Plant Cells
Stromules are dynamic tubular extensions of plastids in plant cells. Present across flowering plants, they reshape rapidly and may aid plastid interactions, molecular exchange or signaling; research is ongoing.
Stromules are thin, tubular extensions that form on the surface of plastids inside plant cells. These structures contain plastid stroma and can change shape and length quickly, projecting away from organelles such as chloroplasts.
Historical observations
Descriptions of plastid protrusions date back to the late 19th and early 20th centuries, with reports from 1888 and 1908 noting outgrowths and connections between plastids. Interest in these features increased after they were brought back to attention in 1997, when modern imaging made their presence and dynamics clearer.
Researchers continue to investigate stromules. Their transient, often branching form suggests roles in increasing plastid surface area, facilitating molecular exchange between plastids and other cell compartments, or in signaling, but none of these functions has been definitively established.
Questions and Answers
Q: What is a stromule?
A: A stromule is a microscopic structure found in plant cells that extends from the surface of all plastids, including chloroplasts.
Q: When were protrusions from and interconnections between plastids first observed?
A: Protrusions from and interconnections between plastids were seen in 1888 and 1908.
Q: When were stromules rediscovered?
A: Stromules were recently rediscovered in 1997.
Q: In which plant species do stromules exist?
A: Stromules exist in a number of angiosperm species including Arabidopsis thaliana, wheat, rice and tomato.
Q: Are the roles of stromules in plant cells fully understood?
A: No, the roles of stromules in plant cells are not yet fully understood.
