Q31 / 200 · NEET 2005 · Botany

All of the following statements concerning the actinomycetous filamentous soil bacterium Frankia are correct except that Frankia:

  • Correct answer
    A
    can induce root nodules on many plant species
  • B
    can not fix nitrogen in the free-living stale
  • C
    can not fix specialized vesicles in which the nitrogenase is protected from oxygen by a chemical barrier involving triterpene hopanoids
  • D
    like Rhizobium, it usually infects its host plant through root hair deformation and stimulates cell proliferation in the host's cortex.

Solution

Frankia is a genus of filamentous, nitrogen-fixing bacterium and it forms a symbiotic relationship with many plants. It causes root hair deformation in a way that it enters the cortical cells and induces the nodule formations, which look like those induced by Rhizobium in legumes. It is associated symbiotically with the root nodules of several non-legume plants like Casuarina, Alnus, Rubus etc. It cannot fix nitrogen in free state.

Hence, the correct answer is option: 'A'.

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