Arabidopsis hydathodes contain a dense and heterogeneous epithem for apoplastic fluid release
Yagi, H.; Mihara, I.; Ikeda, T.; Sano, R.; Demura, T.; Hara-Nishimura, I.; Shimada, T.; Ueda, H.
Plant Signaling
Those glistening water droplets on your strawberry or tomato leaves at dawn aren't just dew—they're being actively pushed out through specialized organs that may carry compounds from deep inside the plant, which could help explain how some leaf diseases start at leaf tips.
Plants sometimes 'cry' tiny water droplets from their leaf tips overnight—a process called guttation. Scientists looked closely at the tiny organs responsible in a common lab plant and discovered they're made of a surprisingly varied mix of cell types packed tightly together. They also found that the water released isn't pure—it contains material from the spaces between cells, suggesting these structures do more than just drain excess water.
Key Findings
X-ray CT imaging showed hydathode tissue is more densely packed than surrounding leaf tissue and protrudes from the underside of the leaf surface.
Light microscopy revealed the epithem (the core tissue of the hydathode) is heterogeneous—with elongated cells near the veins and rounded cells toward the pore—and is enclosed by a ring of plastid-containing 'boundary cells' resembling mesophyll cells.
Transgenic plants expressing a secreted GFP marker confirmed that guttation droplets contain apoplastic (cell-wall-space) fluid, not just water filtered from the vascular system.
chevron_right Technical Summary
Researchers mapped the detailed structure of hydathodes—tiny leaf-tip organs that release water droplets (guttation) in Arabidopsis—finding that their inner tissue is denser and more varied in cell type than previously known, and that the released water carries material from inside the plant's cell walls.
Abstract Preview
Hydathodes are specialized leaf tissues that mediate guttation, the release of liquid water droplets from vascular plants. They consist of xylem endings, water pores, and the epithem. The epithem c...
open_in_new Read full abstractAbstract copyright held by the original publisher.
Species Mentioned
Was this useful?
Want to tell us more? (optional)
Thanks for the note!
Something went wrong — please try again.
Too many submissions. Try again in an hour.
Nanoplastics interfere with plant-mycorrhizal communication and limit plant growth.
Microplastics breaking down in your garden soil are quietly strangling the beneficial fungi that help your vegetables absorb phosphorus and other nutrients, ...
Arabidopsis (rockcress) is a genus of small flowering plants in the cabbage and mustard family, Brassicaceae. Arabidopsis species are native to temperate and subarctic Eurasia and North America, North Africa, and the mountains of eastern tropical Africa. This genus is of great interest since it c...