Abstract:

Vessels are the conduit for water transport in xylem of most angiosperms. Our knowledge on their structure remains crucial in understanding the hydraulic properties of angiosperms and their adaptability to the changing environment. Vessel length is one of the major anatomical features that play a fundamental role in determining the trade-offs between safety and efficiency of long-distance water transport in xylem. This article provides a review of scholarly research on the structure and function of plant vessels, as well as the corresponding methods, measurements, scientific challenges on the influence on vulnerability curve and the relationships with other features of vessel length, as well as our knowledge gaps. Future efforts should be placed on: 1) improvement of the materials for penetration for their completion, easy-to-use, measurement accuracy, and new technology; 2) sound research on vessel network of different organs, as well as a database on vessels of different functional groups and climate zones; 3) the change in vessel diameter and other structural features with length; 4) optical measurements of xylem vulnerability for additional evidences on the roles of artificial open vessels. Advancing our knowledge on the role of vessel length in hydraulic function of plants will provide us with a theoretical foundation for improvement of drought-tolerant and drought-resistant species.

Key words: paint injection, air injection, vulnerability curves, hydraulic characteristics