Endogenous plant growth substances have been implicated incontrolling many developmental processes of plants (Wilkinsonand Davies, 2002; Yang et al., 2004; Zhang et al., 2007). Liu et al.(2010) reported that ABA concentration in seed was positively cor-related with seed-filling rate. Similarly, a decrease in the rate ofdry weight accumulation was associated with a sharp decline inABA concentration. ABA may be involved in the stimulation of rapidunloading of sucrose into the testa of soybean and the ABA in cotyle-dons may enhance sucrose uptake by the cotyledons (Schussleret al., 1984).