Whenever I teach on seeds, either in my non-majors Food class or my Plant Physiology class for majors, I can’t help describing them as the children of the mother plant. I know, not exactly creative, but it helps to paint a picture of the roles of the parent plant and the seed. I like to talk about how the endosperm or other food reserve is like a packed lunch, put there by the caring mother to feed the baby plant as it germinates and becomes able to feed itself. And what kind of parent sends its babies out without a coat? It usually gets a few chuckles, at least, to put this all in human terms.
That coat on the seed? Sometimes it’s a jacket, and other times it’s more like a down coat, and the mother plant chooses based on the temperature. I’m not making this up. In a study published this week, plant scientists link the toughness/thickness of the seed coat to the temperature endured by the mother plant. If the mother experienced warmer temperatures, it will make more of a protein that limits the production of tannins in the fruit. Less tannin makes for a thinner seed coat and faster germination. On the other hand lower temperatures cause the mother plant to make more tannins, leading to a thicker coat. Simple, yet remarkable.