Mineral Nutrition

The function of leghaemoglobin in the root nodules of legumes is

1. inhibition of nitrogenase activity
2. oxygen removal
3. nodule differentiation
4. expression of nif gene

Leguminous plants are able to fix atmospheric nitrogen through the process of symbiotic nitrogen fixation. Which one of the following statements is not correct during this process of nitrogen fixation?

1. Leghaemoglobin scavenges oxygen and is pinkish in colour.
2. Nodules act as sites for nitrogen fixation.
3. The enzyme nitrogenase catalyses the conversion of atmospheric N2 to NH3.
4. Nitrogenase is insensitive to oxygen.

Study the cycle shown below and select the option which gives correct words for all the four blanks A, B, C and D. [figure]

1. array|l|l|l|l| A & B & C & D \ Nitrification & Ammonification & Animals & Plants \ array
2. array|l|l|l|l| A & B & C & D \ Denitrification & Ammonification & Plants & Animals \ array
3. array|l|l|l|l| A & B & C & D \ Nitrification & Denitrification & Animals & Plants \ array
4. array|l|l|l|l| A & B & C & D \ Denitrification & Nitrification & Plants & Animals \ array

One of the free-living, anaerobic nitrogen-fixer is

1. Beijerinckia
2. Rhodospirillum
3. Rhizobium
4. Azotobacter

An element playing important role in nitrogen fixation is

1. molybdenum
2. copper
3. manganese
4. zinc

Which one of the following is not a micronutrient?

1. Molybdenum
2. Magnesium
3. Zinc
4. Boron

Manganese is required in

1. plant cell wall formation
2. photolysis of water during photosynthesis
3. chlorophyll synthesis
4. nucleic acid synthesis

Nitrogen fixation in root nodules of Alnus is brought about by:

1. Bradyrhizobium
2. Frankia
3. Clostridium
4. Azorhizobium

Which of the following is a flowering plant with nodules containing filamentous nitrogen-fixing micro-organism?

1. Crotalaria juncea
2. Cycas revoluta
3. Cicer arietinum
4. Casuarina equisetifolia

Which one of the following elements is not an essential micronutrient for plant growth?

1. Zn
2. Cu
3. Ca
4. Mn

A plant requires magnesium for

1. protein synthesis
2. chlorophyll synthesis
3. cell wall development
4. holding cells together

Sulphur is an important nutrient for optimum growth and productivity in

1. oilseed crops
2. pulse crops
3. cereals
4. fibre crops.

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

1. can induce root nodules on many plant species
2. can fix nitrogen in the free-living state
3. forms specialized vesicles in which the nitrogenase is protected from oxygen by a chemical barrier involving triterpene hopanoids
4. like Rhizobium, it usually infects its host plant through root hair deformation and stimulates cell proliferation in the host's cortex.

The deficiencies of micronutrients, not only affect growth of plants but also vital functions such as photosynthetic and mitochondrial electron flow. Among the list given below, which group of three elements shall affect most, both photosynthetic and mitochondrial electron transport?

1. Co, Ni, Mo
2. Ca, K, Na
3. Mn, Co, Ca
4. Cu, Mn, Fe

If by radiation all nitrogenase enzymes are inactivated, then there will be no

1. fixation of nitrogen in legumes
2. fixation of atmospheric nitrogen
3. conversion from nitrate to nitrite in legumes
4. conversion from ammonium to nitrate in soil.

Plants deficient of element zinc, show its effect on the biosynthesis of plant growth hormone

1. auxin
2. cytokinin
3. ethylene
4. abscisic acid.

Gray spots of oat are caused by deficiency of

1. Cu
2. Zn
3. Mn
4. Fe

Boron in green plants assists in

1. activation of enzymes
2. acting as enzyme co-factor
3. photosynthesis
4. sugar transport

Enzyme first used for nitrogen fixation

1. nitrogenase
2. nitroreductase
3. transferase
4. transaminase

Passive absorption of minerals depends on

1. temperature
2. temperature and metabolic inhibitor
3. metabolic inhibitor
4. humidity

Roots of which plant contain a red pigment which has affinity for oxygen?

1. Carrot
2. Soybean
3. Mustard
4. Radish

Mg is a component of

1. chlorophyll
2. cytochrome
3. haemoglobin
4. haemocyanin

Plants take zinc in the form of

1. ZnSO4
2. Zn2+
3. ZnO
4. Zn

When the plants are grown in magnesium deficient but urea rich soil, the symptoms expressed are

1. yellowish leaves
2. colourless petiole
3. dark green leaves
4. shoot apex dies