Bacteria in the soil enhance the attractiveness of the plant's flowers to pollinators via a type of relationship known as mutualism that is widespread in plants and animals. Microorganisms such as bacteria or fungi contribute to and benefit from mutualistic relationships with plants, whereby both sides obtain more nutrients or reproduce more vigorously, for example.
In the case of C. latistipula, a shrub with a native range spanning Bolivia, Brazil and northeast Argentina, the soil it inhabits tends to be nutrient-poor, and it depends on a specific type of pollinator to reproduce.
"Its mutualistic relationship with nitrogen-fixing bacteria increases the supply of the nutrient to its roots in exchange for the sugar on which they feed," said Anselmo Nogueira, a professor at the Federal University of the ABC's Center for Natural and Human Sciences (CCNH-UFABC) in São Bernardo do Campo, São Paulo state, Brazil.
"The plant also has a mutualistic relationship with a specific type of pollinator. The pollen stored in its flowers' anthers is only released when they are made to vibrate, mainly by being shaken by females of some species of bumblebee in the genus Bombus."
A greenhouse experiment conducted at the Plant-Animal Interaction Laboratory, which Nogueira heads, showed that these bacteria play a significant role in making flowers attractive to bumblebees, especially for plants growing in nutrient-poor soil.
"We also observed a drastic effect that we hadn't expected. Because the association with bacteria is very costly for the…
André Julião
phys.org