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The water-filled versus air-filled status of vessels cut open in air: the 'Scholander assumption' revisited


H. Cochard
P. Cruziat



Publication type:

Scientific Journal (JRNL)

Primary Station(s):

Northern Research Station

Historical Station(s):

Northeastern Research Station


Plant, Cell and Environment. 26: 613-621


When petioles of transpiring leaves are cut in the air, according to the 'Scholander assumption', the vessels cut open should fill with air as the water is drained away by continued transpiration, The distribution of air-filled vessels versus distance from the cut surface should match the distribution of lengths of 'open vessels', i.e. vessels cut open when the leaf is excised. Three different methods were used to estimate the length distribution of open vessels and compared it to the observed distribution of embolisms by the cryo-scanning electron microscope (SEM) method. In the cryo-SEM method, petioles are frozen in liquid nitrogen soon after the petiole is cut. The petioles are then cut at different distances from the original cut surface while frozen and examined in a cryo-SEM facility, where it is easy to distinguish vessels filled with air from those filled with ice. In petioles of Acer platanoides and Juglans regia, the distribution of embolized vessels agrees with expectations. This is in contrast to a previous study on sunflower where cryo-SEM results did not agree with expectations. The reason for this disagreement requires further study for a full elucidation.


Tyree, M.T.; Cochard, H.; Cruziat, P. 2003. The water-filled versus air-filled status of vessels cut open in air: the ''Scholander assumption'' revisited. Plant, Cell and Environment. 26: 613-621

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