Exam 31: Microorganisms in Terrestrial Ecosystems

A mineral soil contains less than 20 percent organic carbon while an organic soil contains at least that amount.

In a mycorrhizal relationship,the fungal component can assist in providing phosphorus and water to the plant.The plant in turn provides the fungus with ________.

Which fungi are responsible for infecting hundreds of plant species and cause the loss of millions of pounds of produce each year?

A fungus that destroys host plant cells by releasing toxins and enzymes would be categorized as which of these?

The stems and leaves of plants,called the ___________,provide a habitat for a wide variety of microorganisms.

An important bacterial mediated process that occurs on the surface of plant roots is called _________ nitrogen fixation. or

In the process of forming a root nodule,species of Rhizobium differentiate to form a type of cell called a ________.

In bog soils,the decomposition rate of lignin-cellulose complexes is accelerated by the water-logged,predominately anoxic conditions.

Agrobacterium has the ability to infect plants and produce tumor-like growths.

Most ectomycorrhizae produce signaling molecules that limit the growth of root hairs.

A large reserve of methane is found in a pocket below the ocean floor and isotope analysis revealed that the ¹³C/¹²C ratio is lower than that predicted by the natural occurrence of these isotopes.This finding suggests that the methane was produced by ______.

Rhizobium and Bradyrhizobium are significant contributors to which process when engaged in a symbiotic relationship with leguminous plants?

The formation of an infection thread is an important initial part of microbial interactions with plants in the process of ________.

Bacteroids are terminally differentiated-they can neither divide nor revert back to the nondifferentiated state.

A substance that promotes binding of Rhizobium to plant root hairs is called a __________ factor. or

Ti plasmids in the species Agrobacterium tumefaciens

Filamentous fungi found in soils are able to form bridges across aggregates and facilitate nutrient transfer processes.