Corn Asks "Who's Your Daddy?"

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Corn seems to be kind to its closest kin. Kernels fertilized by the same father grow larger embryos than kernels resulting from different fathers.

A corn kernel has two distinct parts, the embryo and the endosperm, that can be genetically different from each other. The endosperm is the white starchy filling of the corn kernel that explodes into a puff of popcorn. The embyro is the little yellowish bit found at the base of the kernel when eating corn-on-the-cob. The embryo spouts and grows into the plants that cover much of the central United States. The endosperm feeds the embryo, sacrificing itself so that its seedmate sibling can live.

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The embryo and the endosperm are usually fertilized by two pollen grains from the same male plant. However, in rare cases, one male’s pollen fertilizes the embryo, while a different papa plant fertilizes the endosperm.

Biologist recently found that when that happens, the endosperm seems less willing to give up its energy reserve to a half-sibling embryo.

“The results indicated embryos with the same mother and father as the endosperm in their seed weighed significantly more than embryos with the same mother but a different father,” said study co-author Pamela Diggle of the University of Colorado in a press release.

The different-daddied embryos were runts event though the endosperms sharing their kernels were of roughly equal weight to those in kernels with a single father.

“We found that endosperm that does not share the same father as the embryo does not hand over as much food — it appears to be acting less cooperatively.”

The authors suggested that the interaction between embryo and endosperm was a form of altruism. The genetic favoritism however means that when a nutrition-granting endosperm is stingy, the other kernels that likely do share the same father will have a greater chance of survival.

Endosperms don’t just give up their energy to plant embryos. Humans depend on the carbohydrate-rich endosperms of grains for sustenance.

“The tissue in the seeds of flowering plants is what feeds the world,” said co-author William Friedman of Harvard University. “If flowering plants weren’t here, humans wouldn’t be here.”

So next time you eat corn-on-the-cob, check the kernels for signs that a half-sibling rivalry could be upsetting that delicious endosperm.

IMAGES:

A woman eating corn. (Bengt Nyman, Wikimedia Commons)

An illustration of the inside of a seed (Jkwchui, Wikimedia Commons)

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