View article

Resistance to xylem cavitation depends on the size of xylem pit membrane pores and the strength of vessels to resist collapse or, in the case of freezing‐induced cavitation, conduit diameter. Altering these traits may impact plant biomechanics or water transport efficiency. The evergreen sclerophyllous shrub species, collectively referred to as chaparral, which dominate much of the mediterranean‐type climate region of southern California, have been shown to display high cavitation resistance (pressure potential at 50% loss of hydraulic conductivity; P₅₀). We examined xylem functional and structural traits associated with more negative P₅₀ in stems of 26 chaparral species. We correlated raw‐trait values, without phylogenetic consideration, to examine current relationships between P₅₀ and these xylem traits. Additionally, correlations were examined using phylogenetic independent contrasts (PICs) to determine …