Field of Science

Unusual tomato plants

OK, quick tomato growers quiz. What's wrong with these tomato plants? Nothing actually; they are normal enough tomato seeds sprouting normal enough tomato plants. What makes them unusual is that they are sprouting from inside an intact tomato fruit, and you don't see this happen very often.

Like many plants, seeds inside tomatoes are inhibited from germinating. Fleshy fruits function by attracting and rewarding animal seed dispersers, and they broadly fall into two categories: fruits with many small seed and fruits with few, large-seeds. The former get eaten with the fruit, pass through the GI tract unscathed, and get deposited in a nitrogen rich environment ready to grow. Some seeds actually require passage through the GI tract to readily germinate. The seeds are numerous enough that while a few get destroyed by chewing, the majority get swallowed intact. And the digestion process removes the inhibiting tissue from around the seed, and may even render the seed coat more permeable.

When seeds get larger, animal dispersers like ourselves generally pick them out and discard them rather than swallowing them. Something about the size of a watermelon seed is about the break point on swallowing versus picking out. Fruits with big seeds (grapefruit) or pits (inner part of fruit with enclosed seed) like peaches and mangos are no brainers. You can follow fruit eating monkeys through a rainforest and see, based on what they drop and defecate (don't follow too closely), that their choices are very similar to yours.

For some reason, probably having something to do with the way it was stored, the environmental conditions overroad the inhibitors and kicked these tomato seeds into premature germination, so here they are growing their way out of the fruit.
HT to a curious botanical colleague.


Larissa said...

I like this.

Anonymous said...

Phactor, you're the bomb.


ilex said...

That's amazing. I can only hope it will never happen to my beloved Paul Robesons.

The Phytophactor said...

Dear Holly,
It won't happen if you eat them sooner rather than later.