CARBOHYDRATES ARE NOT THE SOLE FACTOR DETERMINING DESICCATION TOLERANCE IN SEEDS OF ARABIDOPSIS-THALIANA

ABA-deficient (aba-1) and ABA-insensitive (abi3-1) double mutant seeds of Arabidopsis thaliana are desiccation-intolerant. Carbohydrates are supposed to fulfill a role in membrane protection during dehydration. Desiccation tolerance can be induced in double mutant seeds in vivo by supplying the ABA-analog LAB 173 71 1 to the plant root system. However, this does not lead to significant changes in the carbohydrate composition. In contrast, in vitro incubation of dissected immature seeds with ABA induced desiccation tolerance concomitant with an increase in the seed raffinose content. Thus, different desiccation tolerance-inducing treatments show contradictory effects on seed carbohydrate composition and accumulation. It is concluded that, although carbohydrates might be involved in membrane protection or glass formation during dehydration, it is unlikely that they are the sole factor determining desiccation tolerance in Arabidopsis seeds.