The effect of DAG and DAG kinase inhibitor (DAGKI) on aleurone protoplasts. (A) Freshly isolated protoplasts were treated with GA (5 μM), ABA (5 μM), DAG (1,2-dioctanoyl-sn-glycerol; 50 μM), and DAG kinase inhibitor (R59949; 10 μM). After 48 hr, secreted α-amylase activity was assayed. (B) The effect of DAG kinase inhibitor on aleurone DAG kinase. Protein was extracted and DAG kinase activity assayed in the presence a range of DAGKI concentrations as described in Materials and Methods. Data represent mean ± SEM, n = 3.