Toxicity of Micronutrients

Q. Prominent symptom caused by manganese toxicity is

1. delay in flowering
2. necrosis i.e death of tissue maybe in leaves
3. brown spots encompassed by chlorotic veins
4. none of the above

Q. Assertion (A): The symptoms of manganese toxicity are actually the deficiency symptoms of Fe, Mg and Ca.
Reason (R): Mn competes with Fe and Mg for uptake and also inhibits Ca translocation in the shoot apex.

1. Both A & R are true and R explains A
2. Both A & R are true and R does not explain A
3. A is true and R is true
4. Both A & R are false

Q. Identify the correct statement with regard to manganese toxicity:

1. Manganese toxicity increases magnesium uptake and helps it to bind with the enzymes
2. Manganese toxicity leads to stunted growth
3. Manganese toxicity inhibit calcium translocation in shoot.
4. Manganese toxicity leads to increase in iron uptake

Q. Select an incorrect option.

1. A moderate increase or decrease of trace elements causes deficiency and toxicity respectively
2. Toxicity of manganese causes deficiency of calcium
3. Water & mineral elements are tranported via xylem
4. None of the above

Q.

A micronutrient causes toxicity when:

1. Its concentration is higher than required by the plant

2. Its concentration in a tissue reduces the dry weight of the tissue by about 10%

3. Its concentration results in symptoms like necrosis or chlorosis

4. Its concentration in a tissue inhibits the action of certain enzymes

Q.

Plants usually require micronutrients in very low concentrations. However, if the concentration of micronutrients increases, it leads to ________.

1. Toxicity

2. Cell differentiation

3. Cell elongation

4. Deficiency symptoms

Q.

Which one of the following symptoms is not due to manganese toxicity in plants?

1. Calcium translocation in shoot apex is inhibited

2. Deficiency in both iron and magnesium is induced

3. Appearance of brown spot surrounded by chlorotic veins

4. None of the above