4. Discussion
Flower bud opening of roses is a process of irreversible petal growth in which existing cells expand and fresh and dry weights increase (Faragher et al., 1984; Reid and Evans, 1986; Evans and Reid, 1988). In the present study, petal FW of cut flowers did not increase as much as that of the attached flower, although it increased until 2 days after harvest (Fig. 2). Also, cut flowers har- vested at TB and MB fully opened under postharvest conditions in the same way as attached flowers (data not shown). Moreover, petal FW of cut flowers harvested at the tight bud stage (TB) became lower compared with that ini flowers harvested at the mature bud stage (MB). Soluble carbohydrate contents were also high in the attached flower during flower opening compared with cut flow- ers (Fig. 3). On the other hand, in cut flowers, soluble carbohydrate decreased after harvest and remained low during flower opening in spite of the 1% glucose treatment (Fig. 3). Sucrose content especially decreased soon after harvest in cut flowers irrespective of the date of harvest. However, sucrose content in leaves was kept at a high level in cut flowers even without sugars in the vase solution (data not shown). Thus we considered that sucrose translocation from leaves to petals seemed to decrease after harvest in cut rose flowers.