Recalcitrant seeds are not only desiccation-sensitive, but also metabolically active. In contrast, orthodox seeds, owing to their dry state, are metabolically quiescent. Lowering the water content to a level that would preclude germination but facilitate vital metabolism has been suggested as a way to extend the life-span of recalcitrant seeds in hydrated storage. However, Daniel Côme and Françoise Corbineau of the Université Pierre et …showed first 75 words of 488 total…

…showed last 75 words of 488 total…seed size. The answer lies in reducing both. We had already begun to make progress in overcoming the obstacles posed by hydration. We previously had observed that the faster the seeds could be dried, the greater the degree of water loss that recalcitrant seeds would tolerate. But large recalcitrant seeds lose water only slowly even under conditions that hasten dehydration. Generally, therefore, the seed dies when its tissues are still too wet to be frozen.