Question

Bars of Sanio are the
A. Unthinking cellulose walls between bordered pits of pine wood
B. Thickened boundaries between pits of pine woods
C. Rings around the tours of all gymnosperms wood
D. Modularly ray cells with bar like orientation in Ephedra

Answer 1

Bars of Sanio are present at the junction of the walls of xylem and the cambial cells. Another name for the bars of sanio is crassula. Pits in the pine woods are the longitudinal areas made up by the tangential walls of the tracheids, cambium and the xylem vessels. Ray cells extend in a radial direction.

Complete answer:
The pits in the pine plant are circular and bordered. The pits of the pine wood are the largest known and can be easily demonstrated. The pits form a compound aperture. These borders of the pits in pinus plant together form the Bars of Sanio. If cut in the cross section, the pits appear to be more of a donut shape. The boundaries of the pits are actually made up of remnants of the cells that are hydrolyzed.
The major function of the bars of Sanio is to prevent the passage of large water bubbles to the top of the plant thus avoiding complications due to the bubble formation. The bars of Sanio (actually the boundaries of the pit) are composed of cellulose and pectin. These bars are in the shape of an imperfect tube. These are more commonly seen in woody plants. They grow parallel to the walls of the xylem and not radially.

Hence, the correct answer is option (A).

Note: The bars of Sanio are a part of the xylem vessels especially, the tracheid cells of the xylem. Xylem is the vessel which bears the responsibility of transporting the water from the roots of the plant to the top. Phloem vessels are the ones to transport the food from the top to the other parts of the plant. This prevention of air bubbles from travelling to the top may be referred to as preventing air embolism in the plant.