Very few things in the world of botany are as remarkably mind-blowing to me as seeds. In fact, if I thought I could get away with it, I’d change the name of this column to, “Seed Head,” and write about them for evermore. There’d be themed bumper stickers, of course, that read, “Heed the Seed,” and t-shirts that asked, “What would a seed do?”
On pure aesthetics alone, they’re fascinating! Occurring in a huge array of shapes, sizes and textures, and in as many hues as a box of crayons, seeds deserve an art genera all their own.
But it’s the majesty that lies within that keeps me in a perpetual state of awe. No matter how many times I observe its unfolding, the intrigue never fades.
What is a seed, anyway? Well, let’s peek inside.
Seemingly dead and lifeless, seeds (when environmental conditions agree) are everything but! Generally speaking, within every seed lies tiny embryonic plant (complete with leaves, stem and root), and food storage structures that provide energy until the plant emerges from the soil and begins to make its own.
Precious cargo like this requires tough protective armor; a seed coat. Varying in thickness and hardness from species to species, it’s the seed coat that regulates when and where a seed will ultimately germinate. The thicker the coat, the more grinding by shifting soil particles during rain (or manual scarification by gardeners) is required before water is allowed to penetrate and germination is set in motion.
This is crucial, for it’s how a seed determines when conditions are ideal for germination and survival. For example, seedlings in temperate zones, like ours, would surely die if not well established before the onset of winter. However, a thick seed coat ensures dormancy until winter’s freezing and thawing cycles wears down the coat just in time for spring and the favorable conditions she brings.
And when the time is right, it’s go time!
As water begins to penetrate the seed coat, the seed enters into the most intense period of metabolic activity found in the plant world!
Like a sponge, the seed’s cells absorb the water, soften and swell. The seed coat, unable to keep up with the swelling, rips open, allowing the embryo and seed leaves, the embryo’s energy source, full access to the soil’s water and oxygen.
Drunk on oxygen, a dizzying flurry of chemical activity ensues. Food is broken down and translocated from the seed leaves to the embryo. Energized, the embryonic plant thrusts its root into the loose soil, anchoring the new plant, while simultaneously taking up sustaining minerals and absorbing even more water.
Next, it’s the shoot’s turn to take the stage. Like a hook, the shoot lengthens, pulling the new leaves through, up and out of the soil with more drama than a Broadway production.
And just like that, the plant leaves the toughest state it will ever know and enters into its most vulnerable.
Be careful, little guy. It’s a big and mighty world out there!