A fundamental problem that arises with all of life on earth is allocating a limited number of resources over the entire span of a population. Since the dawn of humanity, this has been the source of countless wars and conflicts that have resulted in the tragic deaths of many and the injury of countless more. In the ancient Arabian Peninsula, the immense lack of water in the scorching predominately desert region (where temperatures can sometimes rise upwards of 130 degrees), caused the nomadic Bedouin tribes to quarrel over the ownership and usage rights of an extremely limited number of wells. Interestingly, recent research conducted by a team from Penn State University and the University of the Negev-Israel have found that the conflict that arises in response to this dilemma of allocating a limited number of resources to a vast diversity of life is not unique to humans or even other animals for that matter, but rather, plants have also been shown to exhibit this sort of discriminatory behavior.

The question of interest that sparked interest in this topic came in attempting to determine the underlying mechanism that helps plants determine who is a rival when competing for a limited amount of water, minerals, and other essential nutrients required to sustain plant life. In order to answer this question, the research team derived a two-part experiment. First, the team determined they needed to know if plants were able to recognize their own roots, and if they were, did they avoid competing with themselves?

To test this, the researches placed plants with bifurcated roots in specially designed chambers that forced the roots to grow apart from each other and to grow away from neighboring plants. Dr. Omer Falik, one of the leaders of the research team at Penn State said of team’s findings, “We found that the roots grew significantly more and longer secondary roots on the non-self side”.

The second part of this study was to then determine ,via a complex experimental process, whether or not this mechanism for discrimination in plants had a chemical or physiological basis. The research team was able to conclude that, at least in the plants observed, the so called “self/non-self root discrimination” relies upon a physiological coordination between roots of the same plant. Though this aspect of this complex coordination of plants is now understood at an elementary level, the underlying hormonal and/or electric signals responsible for this coordination are currently the subject of ongoing research.

Despite attempts by humans at portraying ourselves as above the rest of life on earth, it always comes as a surprise when we discover that our behavior sometimes mirrors that of many of our long-lost evolutionary brothers and sisters.

News article link: http://www.sciencedaily.com/releases/2005/08/050811104308.htm

Scientific article: Implications of self/nonself discrimination for spatial patterning of clonal plants. Evolutionary Ecology 22 (3). Another paper by the author on the same topic: http://www.jstor.org/pss/3599566

Question: Given your knowledge of hormonal interactions in plants, what sort of hormonal and/or electric signals do you think are responsible for this physiological coordination in plants?