| Ultradry storage improves seed longevity and vigor. It is a cost-effective technique for germplasm conservation.As we all know that optimum storage condition can maximize the benefit on seed longevity from dessication. On the basis of feasibility of ultradry seed storage, starch rich seeds of Maize (Zea mays L.), oil rich seeds of Brassica caulorapa Pasq., and short lived seeds of two Allim species, Welsh onion (Allium fistulosum L.) and Chinese chive onion (A. odorum L.), were chosen for further investigation on the seed optimum storage condition.In the meantime, in order to better understand the physiology during seed storage, the mechanisms of seed ageing under different storage conditions were explored to provide more stable theory and practical proofs for ultradry seed storage technology. The main results were summarized as follows:1. Seed viabilities of Welsh onion (Allium fistulosum L.) and Chinese chive onion (A. odorum L.) were monitored during hermetic storage at 50oC, 35oC and 20oC with seed moisture contents (MC, fresh weight basis, %) ranging from 13.9% to 1.5% for Welsh onion, and from 14.5% to 1.8% for Chinese chive onion. Ultradrying treatment showed no adverse significant effect on seed germination and vigor index in both species. It also improved the storability of the seeds a lot.2. The critical moisture contents (mc) of Welsh onion determined at 50oC, 35oC, 20oC were 3.85%, 4.06% and 6.52%, respectively. While the mc of Chinese chive onion were below 1.8% at both 50oC and 35oC, and can be decreased to 4.64% at 20oC. The mc varies according to the storage temperature. It decreased as the storage temperature increased. This observation has important significance in germplasm conservation as well as in agriculture and horticulture.3. The seed viability constants for Welsh onion were KE=7.6964, CW=4.5547, CH=0.0999,CQ=0.000333; while for Chinese chive onion, the seed viability constants were KE=5.0990, CW=3.3385, CH=0.0805,CQ=0.002182, which can be...
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