Water stress, xylem hydraulic failure and tree death

Water stress, xylem hydraulic failure and tree death

Water stress, xylem hydraulic fail­ure and tree death

Extreme water stress epis­odes induce tree mor­tal­ity, but the mech­an­istic rela­tion­ships link­ing stem embol­ism and spe­cies drought per­form­ance remain poorly under­stood. Barigah et al. study pot­ted juven­ile trees of beech (Fagus sylvat­ica) and pop­lar (Populus deltoides × P. nigra) and find that the xylem pres­sure indu­cing 50 % mor­tal­ity dif­fers sharply between the spe­cies, being 1.75 and 4.5 MPa in pop­lar and beech, respect­ively. However, the rela­tion­ships between tree mor­tal­ity and the degree of cavit­a­tion in the stems are sim­ilar, with mor­tal­ity occur­ring sud­denly when >90 % cavit­a­tion has occurred. This is in con­trast to the 50 % embol­ism threshold repor­ted for con­ifers. The res­ults demon­strate that massive cavit­a­tion is prob­ably a causal factor for tree mor­tal­ity under extreme water stress conditions.

Annals of Botany Office.

The Annals of Botany Office is based at the University of Leicester.

Pin It on Pinterest

Liked this?

Be the first to share this post with your friends!