Sugar homeostasis is compromised in scr and shr. A, Glc, Fru, and Suc contents (mg g−1 fresh weight) in leaves of 10-d-old wild-type (Ws and Col), scr-1 and shr-2 plants, measured by HPLC. B, Starch content of wild-type (WT) and scr-1 leaves, as revealed by Lugol staining. Left, samples taken in the evening; right, samples taken in the morning.