Abstract:

Physiological characteristics of two northern（Brigitta，Spartan） and two southern highbush blueberry cultivars（Sharpblue，O’Neal）were investigated under water controlled conditions，as to unveil the possible mechanisms of highbush blueberry in response to drought stress and to screen the drought resistant cultivars. Meanwhile，the study also aimed to prove the possibility of using the Subordinate Function method based on physiological parameters to evaluate the drought-tolerance among the blueberry cultivars. The drought resistance capacity of all the four highbush blueberry cultivars were evaluated comprehensively by：The relative water content，content of the lipid peroxidation product （malondialdehyde，MDA），membrane permeation，contents of hydrogen peroxide （H₂O₂） and superoxide radical，the maximum photochemical efficiency of PSⅡ（Fv/Fm）， stomatal characteristics of leaves. The results showed that drought stress decreased the relative water content，Fv/Fm，stoma open rate，stomatal length and stomatal width；Meanwhile，the relative conductivity，MDA content，H₂O₂ and  contents and stomatal density were increased paralleled with the treatment intensity. The drought resistance abilities differed significantly among the four highbush blueberry cultivars，with the drought resistance capacity sequenced as following：O’Neal，Sharpblue，Brigitta ， Spartan. The two-year field trial proved the Subordinate Function method based on physiological parameters could be used as a reliable method to screen the drought-tolerant blueberry cultivars.

Key words: highbush blueberry, drought resistance, oxidative stress, comprehensive evaluation, subordinate function method