Vessel-length determination using silicone and air injection: are there artifacts?

Area of Science:

• Plant Physiology
• Plant Anatomy
• Ecology

Background:

• Xylem vessels are vital for water and nutrient transport in angiosperms.
• Maximum vessel length is a key functional trait influencing plant water transport efficiency.
• Accurate determination of maximum vessel length is essential to avoid artifacts in hydraulic studies.

Purpose of the Study:

• To evaluate the accuracy of air and silicone injection methods for determining maximum xylem vessel length.
• To compare these methods across eight species with varying vessel lengths.
• To introduce and validate a novel RTV141A-only injection method as a reliable reference.

Main Methods:

• Tested air injection and silicone (BLUESIL RTV141A and B) injection methods.
• Employed a novel RTV141A-only injection technique as a reference method.
• Evaluated methods on eight plant species with short, medium, and long vessel lengths.

Main Results:

• Silicone injection consistently underestimated maximum vessel length in all tested species.
• Air injection tended to overestimate maximum vessel length in five out of eight species.
• Underestimation by silicone injection increased with vessel length; air injection overestimation was independent of vessel length.

Conclusions:

• Conventional silicone injection can underestimate xylem vessel length.
• Air injection can overestimate xylem vessel length, especially in species with long vessels.
• RTV141A-only injection is recommended for accurate maximum vessel length determination and method validation.