Which of the following is NOT a direct consequence of Nod factor signaling in the host plant during root nodule formation?
Root hair curling
Formation of infection threads
Cortical cell division leading to nodule primordia formation
Expression of nif genes in bacteroids
Related Questions
In root nodules of legumes, leghaemoglobin is important because it
Transports oxygen to the root nodule
Acts as an oxygen scavenger
Provides energy to the nitrogen fixing bacterium
Acts as a catalyst in transamination
VAM is
Ectomycorrhizae
Endomycorrhizae
Both (a) and (b)
Ectoendomycorrhizae
The enzyme nitrogenase is highly sensitive to oxygen. How do root nodules maintain a low oxygen environment necessary for nitrogen fixation?
Active transport of oxygen out of the nodule
Anaerobic respiration within the bacteroids
Leghemoglobin binds oxygen, buffering its concentration
Thick cell walls of the nodule prevent oxygen diffusion
Nitrogenase catalyzes the conversion of atmospheric nitrogen into which compound in the root nodules of leguminous plants?
Ammonia
Nitrite
Nitrate
Dinitrogen
Which of these is NOT a characteristic feature of the root nodules formed during legume-rhizobia symbiosis?
Presence of chloroplasts in bacteroids
Presence of leghemoglobin
Differentiated bacteroids
Reduced oxygen concentration
A researcher observes that a particular legume mutant forms nodules, but these nodules fail to fix nitrogen. Which of the following gene mutations is MOST likely responsible?
Mutation in nod genes
Mutation in genes encoding flavonoid biosynthesis
Mutation in nif genes
Mutation in genes encoding leghemoglobin
What is the primary benefit for leguminous plants in forming root nodules with nitrogen-fixing bacteria?
Increased water absorption
Protection from pathogens
Access to usable nitrogen
Enhanced photosynthesis
Which one of the following is an amide involved in nitrogen assimilitaion by plants?
Glutamate
Alanine
Asparagine
Serine
Certain mutant legumes exhibit excessive root hair curling in the presence of rhizobia, but infection threads fail to penetrate the cortex. This phenotype is MOST likely due to a defect in:
Flavonoid production by the root
Rhizobial nod gene expression
Nod factor receptor function
Signaling pathway downstream of Nod factor perception, affecting infection thread growth
Which statement is TRUE regarding the protection of nitrogenase from oxygen?
Nitrogenase is insensitive to oxygen.
Oxygen promotes nitrogenase activity.
Leghaemoglobin binds with oxygen in root nodules.
Nitrogen fixation occurs best in aerobic conditions.
