Air bubbles were digitally photographed as they streamed from a severed tertiary vein of a grape leaf submerged in water (inset). The camera was placed at the surface of the water. The air bubbles reveal the open, continuous xylem conduits that allow air to flow from the base of the petiole into tertiary leaf veins. Low-pressure air flow is one of the techniques used to elucidate the interconnectedness of xylem vessels across multiple organs within grapevine. Vineyardgrown Vitis vinifera cv. Cabernet Franc frames the inset.
the AJB Abstract for the article:
The structure of xylem vessels in grapevine (Vitaceae) and a possible passive mechanism for the systemic spread of bacterial disease
by Eleanor T. Thorne, Briana M. Young, Glenn M. Young, Joshua F. Stevenson, John M. Labavitch, Mark A. Matthews and Thomas L. Rost