Accumulation of sugars during the onset and development of desiccation tolerance in immature seeds of Norway maple (Acer platanoides L.) stored moist

The viability of Norway maple seeds collected 21 d before mass maturity (68 % moisture content, wet basis) and at mass maturity (56% moisture content) was reduced from 52-85% to 0-7% if dried rapidly (at 10-12% r.h. and 15-17 degrees C for 3 d, then 3 d over silica gel) to 4-5% moisture content. Mois t storage of the fruits at 15 degrees C improved the ability of the seeds t o tolerate rapid desiccation considerably: 10 and 21 d of moist storage ena bled seeds collected at mass maturity or 21 d earlier, respectively, to att ain maximum desiccation tolerance to 4-5% moisture content. Moist storage a nd/or subsequent desiccation affected stachyose, sucrose, and to a lesser e xtent raffinose, concentrations. The oligosaccharide :total sugar ratio sho wed a similar pattern in relation to ability to germinate after desiccation to 4-5% moisture content among seeds collected on both dates: desiccation tolerance developed from nil to maximal in these seed populations between t hreshold oligosaccharide:total sugar values of just less than 0.3 and about 0.4.