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Cavitation vulnerability in roots and shoots: does Populus euphratica Oliv., a poplar from arid areas of Central Asia, differ from other poplar species?

Abstract：

:Populus euphratica is a poplar species growing in arid regions of Central Asia, where its distribution remains nevertheless restricted to river-banks or to areas with an access to deep water tables. To test whether the hydraulic architecture of this species differs from that of other poplars with respect to this ecological distribution, the vulnerability to cavitation of P. euphratica was compared with that of P. alba and of P. trichocarpa x koreana. The occurrence of a potential hydraulic segmentation through cavitation was also investigated by assessing the vulnerability of roots, stems, and leaf mid-rib veins. Cryo-scanning electron microscopy (cryo-SEM) was used to assess the level of embolism in fine roots and leaf mid-ribs and a low pressure flowmeter (LPFM) was used for stems and main roots. The cryo-SEM technique was validated against LPFM measurements on paired samples. In P. alba and P. trichocarpa x koreana, leaf mid-ribs were more vulnerable to cavitation than stems and roots. In P. euphratica, leaf mid-ribs and stems were equally vulnerable and, contrary to what has been observed in other species, roots were significantly less vulnerable than shoots. P. euphratica was by far the most vulnerable. The water potential inducing 50% loss of conductivity in stems was close to -0.7 MPa, against approximately -1.45 MPa for the two others species. Such a large vulnerability was confirmed by recording losses of conductivity during a gradual drought. Moreover, significant stem embolism was recorded before stomatal closure, indicating the lack of an efficient safety margin for hydraulic functions in this species. Embolism was not reversed by rewatering. These observations are discussed with respect to the ecology of P. euphratica.

journal_name

J Exp Bot

journal_title

Journal of experimental botany

authors

Hukin D,Cochard H,Dreyer E,Le Thiec D,Bogeat-Triboulot MB

doi

10.1093/jxb/eri198

keywords:

subject

Has Abstract

pub_date

2005-08-01 00:00:00

pages

2003-10

issue

418

eissn

0022-0957

issn

1460-2431

pii

eri198

journal_volume

pub_type

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Cavitation vulnerability in roots and shoots: does Populus euphratica Oliv., a poplar from arid areas of Central Asia, differ from other poplar species?