02/05/2013 01:06 pm ET Updated Dec 06, 2017

Plants Can Be Altruistic, Too: CU-Boulder Study Shows

You'll never think of your popcorn the same way: In its previous life, it could have come from an altruistic ear of corn with strong family bonds.

A new University of Colorado-led study suggests that plants have the capability to be altruistic.

(In animals, scientists have long recognized the trait, which makes for cute Internet memes -- dogs caring for orphaned kittens or dolphins helping nudge their injured mates to the surface).

For the newly published study, CU researchers studied corn, in which each fertilized seed contained two "siblings" -- an embryo and a corresponding bit of tissue known as endosperm that feeds the embryo as the seed grows. They compared the growth and behavior of the embryos and endosperm in seeds sharing the same "mother" and "father" plants with those that had genetically different parents.

The results showed that embryos with the same mother and father as the endosperm in their seed weighed significantly more than those with the same mother but a different father, said Pamela Diggle, a CU professor. That means the endosperm can recognize its "half siblings" and is less likely to pass on as much food, thus acting less cooperatively.

The Proceedings of the National Academy of Sciences published a paper on the subject late last month.

Co-authors on the study included Chi-Chih Wu, a CU doctoral student in the ecology and evolutionary biology department, and professor William "Ned" Friedman, a professor at Harvard University who helped conduct research on the project while a faculty member at CU. Friedman and Diggle, a visiting professor at Harvard, are married.

Earlier research showed that plants can hold back nutrients from inferior offspring when resources are scarce.

Friedman said one of the most fundamental laws of nature is if you are going to be an altruist, give up your goods to your closest relatives. The study revealed an ultimate display of altruism: If an endosperm forks over all of its food to the embryo, then it dies.

"Plants, just like humans, do care about who is in their family," Friedman said.

For the research, Wu cultivated the corn and harvested more than 100 ears over a three-year period.

He removed, mapped and weighed every individual kernel from the harvests. Most of the kernels had an endosperm and embryo with matching colors, which indicates they shared the same mother and father plants. But some had different colors -- perhaps a purple outer kernel with a yellow embryo.

Wu took on the time-intensive task of searching for those kernels that had different fathers so that the researchers could examine the cooperation between the embryo and endosperm.

The authors also noted that endosperm is critical to human survival because in wheat, corn and rice, it provides about 70 percent of the calories consumed worldwide.

Contact Camera Staff Writer Brittany Anas at 303-473-1132 or ___