Nitrogen-fixation in root nodules of Alnus is brought about by
Bradyrhizobium
Clostridium
Frankia
Frankia
C.
Frankia
Nitrogen is the most critical element. The atmosphere is the greatest reservoir of nitrogen. Molecular nitrogen cannot be utilised directly by plants. It has to be fixed or converted into compounds prior to utilisation. symbiotic nitrogen fixation is accomplished by Rhizobium species, which occurs on the roots of leguminous plants. Certain non-leguminous plants also form nodules to fix nitrogen. The best-known example in the temperate region is alder (Alnus sp.). The bacteria involved in nodule formation is an Actinomycetes, the frankia.
Clostridium is anaerobic saprotrophic free-living nitrogen-fixing bacteria.
Bradyhizobium is symbiont in plants of parasponia and soybean.
The azohizobium forms both stem and root nodules in Sesbania (aquatic plant).
Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statement is not correct during the process of nitrogen fixation?
Leghaemoglobin scavenges oxygen and is pinkish in colour
Nodules act as a site for nitrogen fixation
The enzyme nitrogenase catalyse the conversion of atmospheric N2 to NH3
The enzyme nitrogenase catalyse the conversion of atmospheric N2 to NH3
Sulphur is an important nutrient for optimum growth and productivity in
pulse crops
cereals
fibre crops
fibre crops
Examination of blood of a person suspected of having anaemia, shows large, immature, nucleated erythrocytes without haemoglobin. Supplementing his diet with which of the following is likely to alleviate his symptoms?
Thiamine
Folic acid and cobalamine
Riboflavin
Riboflavin
Which one of the following elements is not an essential micronutrient for plant growth?
Mn
Zn
Cu
Cu
The two subunits of ribosome remain united at a critical ion level of
Copper
Manganese
Manganese
Manganese
The free-living, anaerobic nitrogen - fixer is
Beijerinckia
Rhodospirillum
Rhizobium
Rhizobium
Manganese is required in
nucleic acid synthesis
plant cell wall formation
photolysis of water during photosynthesis
photolysis of water during photosynthesis
