Washington, Feb 3 (IANS) Dogs adopting orphaned kittens or dolphins nudging injured mates to the sea surface are prime examples of animal altruism. Now new research suggests that plants too share the same trait.
Researchers looked at corn, in which each fertilized seed contained two "siblings" -- an embryo and a bit of tissue known as endosperm that feeds the embryo as the seed grows, explains Pamel diggle, professor of ecology and evolutionary biology at the University of Colorado-Boulder.
They compared the growth and behaviour of the embryos and endosperm in seeds sharing the same mother and father, with that of their counterparts having different parents, the journal Proceedings of the National Academy of Sciences reports.
"The results indicated that 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," says Diggle, according to a Colorado-Boulder statement.
"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," adds Diggle.
Diggle said it is fairly clear from previous research that plants can preferentially withhold nutrients from inferior offspring when resources are limited. "Our study is the first to specifically test the idea of cooperation among siblings in plants."
"One of the most fundamental laws of nature is that if you are going to be an altruist, give it up to your closest relatives," said William "Ned" Friedman, professor at Harvard University who helped conduct the research while still a Colorado faculty member.
"Altruism only evolves if the benefactor is a close relative of the beneficiary. When the endosperm gives all of its food to the embryo and then dies, it doesn't get more altruistic than that," adds Friedman.
Endosperm -- in the form of corn, rice, wheat and other crops -- is critical to humans, providing about 70 percent of calories we consume annually worldwide. "The tissue in the seeds of flowering plants is what feeds the world," said Friedman.