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A comparison of two methods for measuring vessel length in woody plants
Author(s) -
Pan Ruihua,
Geng Jing,
Cai Jing,
Tyree Melvin T.
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12566
Subject(s) - mechanics , yield (engineering) , hagen–poiseuille equation , flow (mathematics) , materials science , mathematics , physics , composite material
Vessel lengths are important to plant hydraulic studies, but are not often reported because of the time required to obtain measurements. This paper compares the fast dynamic method (air injection method) with the slower but traditional static method (rubber injection method). Our hypothesis was that the dynamic method should yield a larger mean vessel length than the static method. Vessel length was measured by both methods in current year stems of A cer , P opulus , V itis and Q uercus representing short‐ to long‐vessel species. The hypothesis was verified. The reason for the consistently larger values of vessel length is because the dynamic method measures air flow rates in cut open vessels. The H agen– P oiseuille law predicts that the air flow rate should depend on the product of number of cut open vessels times the fourth power of vessel diameter. An argument is advanced that the dynamic method is more appropriate because it measures the length of the vessels that contribute most to hydraulic flow. If all vessels had the same vessel length distribution regardless of diameter, then both methods should yield the same average length. This supports the hypothesis that large‐diameter vessels might be longer than short‐diameter vessels in most species.