No oxygen for free

2003/12/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Ekologia

Symbiosis between species is a market, not an exchange of favors among friends. This is what some American biologists have deduced after analyzing the relationship between soy and several bacteria.

Soy and many other legumes produce symbiosis with bacteria that fix nitrogen from the air. The bacteria provide the plant with nitrogen molecules in exchange for oxygen and certain foods.

However, this is a strict relationship, since if bacteria do not supply enough nitrogen to the plant, it does not return oxygen in return. To demonstrate this, biologists have raised them in an atmosphere without nitrogen. The bacteria had no nitrogen available, so they could not offer anything to soy. Consequently, oxygen did not reach the area where the bacteria were.