We find that Rhizobium forms nodules on the roots of leguminous plants. Also Frankia another microbe forms nitrogen-fixing nodules on the roots of non-leguminous plant Alnus.
a. Can we artificially induce the property of nitrogen fixation in a plant – leguminous or non-leguminous?
b. What kind of relationship is observed between mycorrhiza and pine trees?
c. Is it necessary for a microbe to be in close association with a plant to provide mineral nutrition? Explain with the help of one example.
(a) Yes, the property of nitrogen fixation in a plant – leguminous or non-leguminous can be artificially induced by genetic engineering.
(b) Mycorrhiza and Pine trees show a symbiotic relationship. In this type of relationship both the organisms benefit from each other.
(c) Yes, a microbe must be in close association with a plant to provide mineral nutrition.
An example is the rod-shaped Rhizobium has such a relationship with several legumes like sweet pea, lentils, garden pea etc.