How seeds know it's a good time to germinate

(Carnegie Institution for Science) Dehydrated plant seeds can lay dormant for long periods--over 1,000 years in some species--before the availability of water can trigger germination. This protects the embryonic plant inside from a variety of environmental stresses until conditions are favorable for growth and survival. However, the mechanism by which the baby plant senses water and reactivates cellular activity has remained a mystery until now.
Source: EurekAlert! - Biology - Category: Biology Source Type: news