Which one of the following statements can best explain the term critical concentration of an essential element?
1. essential element concentration below which plant growth is retarded
2. essential element concentration below which plant growth becomes enhanced
3. essential element concentration below which plant remains in the vegetative phase
4. None of the above
Deficiency symptoms of an element tend to appear first in young leaves. It indicates that the element is relatively immobile. Which one of the following elemental deficiency would show such symptoms?
Which one of the following symptoms is not due to manganese toxicity in plants?
1. Calcium translocation in shoot opex is inhibit
2. Deficiency in both iron and nitrogen induced
3. Appearance of brown spot surrounded by chlorotic veins
4. None of the above
Reactions carried out by N2 fixing microbes include
Which of the following statements about these equations is not true?
|1.||Step (i) is carried out by Nitrosomonas or Nitrococcus|
|2.||Step (ii) is carried out by Nitrobacter|
|3.||Both steps (i) and (ii) can be called nitrification|
|4.||Bacteria carrying out these steps are usually photoautotrophs|
With regard to the biological nitrogen fixation by Rhizobium in association with soyabean, which one of the following statement/ statements does not hold true.
1. Nitrogenase may require oxygen for its functioning.
2. Nitrogenase is Mo-Fe protein
3. Leg-haemoglobin is a pink coloured pigment.
4. Nitrogenase helps to convert N2 gas into two molecules of ammonia.
Match the element with its associated functions/roles and choose the correct option among given below:
1. Splitting of H2O to liberate O2 during photosynthesis
2. Needed for synthesis of auxins
3. Component of nitrogenase
4. Pollen germination
5. Component of ferredoxin
1) 1, 2, 3, 4, 5
2) 4, 1, 3, 2, 5
3) 3, 2, 4, 5, 1
4) 2, 3, 5, 1, 4
Plants can be grown in
1. soil with essential nutrients.
2. water with essential nutrients.
3. either water or soil with essential nutrients.
4. water or soil without essential nutrients.
Which one of the following roles is not characteristic of an essential element?
1. is a component of biomolecules
2. changing the chemistry of soil
3. being a structural component of energy-related chemical compounds
4. activation or inhibition of enzymes
Which metal ion is a constituent of chlorophyll ?