We recently reported that H 2S could significantly promote the germination of wheat grains subjected to aluminum (Al(3+)) stress.1 In these experiments seeds were pretreated with the H 2S donor NaHS for 12 h prior to Al(3+) stress. During this pre-incubation period we observed that H2S increased the activity of grain amylase in the absence of Al(3+). Using embryoless half grains of wheat we now show that H2S preferentially affects the activity of endosperm β-amylase and that α-amylase synthesis and activity is unaffected by this treatment.