During winter cold spells, concerns are often voiced on how the animals manage to make it through the season. Of course, there is variation in how well-adapted animals are to winter. It is similar with plants, which is exemplified by the development of plant hardiness zones. But how about plant seeds during the winter months? There is probably a lot more going there than most people would think.
Most seeds must go through a dormant period before they can germinate. That dormant period allows time for the seeds to get dispersed away from the parent plant and into new habitats. It can also prevent the seeds from germinating during stressful environmental conditions.
Seed germination is a complex process that involves aspects of embryo and seed coat development as well as environmental factors such as light, moisture, and temperature. Water, for example, is required for germination, so dry conditions will prevent germination. That could, for example, be a problem for desert plants. But interestingly, some desert plants have chemicals on their seed coats that inhibit germination. Those chemicals, called germination inhibitors, must be leached away before the seeds will germinate. It is as if the seeds have a rain gauge on their seed coats to signal when there is enough water present to germinate, and the seedling has a good chance of becoming established.
The seeds of many plants native to temperate climates such as that of North Dakota cannot germinate until they have gone through a considerable cold treatment or stratification. That prevents the seeds from germinating as winter approaches which could be fatal, and helps ensure that the seeds stay dormant throughout the winter months and germinate during better conditions in the next growing season.
Those are just a couple of examples of the many aspects of seed ecology. Winter is loosening its grip, with the spring equinox coming up on March 20. So, give some thought to all those seeds on and in the soil that are lying dormant until the right set of conditions are present for them to germinate and perhaps become a part of the next generation of plants.
