441. Certain chemical substances having profound effect on plant growth are called

A Catalyic
B Phytohormones
C Enzymes
D Compost
Answer :   Phytohormones
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442. Transpiration will increase with the increase of

A Humidity
B Temperature
C Carbon dioxide
D Sulphur dioxide
Answer :   Temperature
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443. Which conditions favours "Guttation

A High water absorption
B High transpiration
C Low transpiration
D A and C both
Answer :   A and C both
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444. When a cell is fully turgid which of the following will be zero

A Turgor pressure
B Wall pressure
C Suction pressure
D Osmotic pressure
Answer :   Suction pressure
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445. Hormone produced during leaf fall is

A IAA
B ABA
C Florige
D Kinetin
Answer :   ABA
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446. The principal pathway of water translocation in Angiosperms is

A sieve cells
B sieve tube elements
C xylem vessel system
D xylem and phloem
Answer :   xylem vessel system
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447. In 0.1 M solution of a non electrolyte, ?w value will be

A Zero bar
B +2.3bar
C -203 bar
D -22.4 bar
Answer :   -203 bar
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448. Humus in soil is necessary for plant growth because it

A Increases aeration and water absorption capacity of soil
B Makes soil compact
C Makes soil sterile
D Decreases rate of percolation
Answer :   Increases aeration and water absorption capacity of soil
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449. Water potential is equal to

A ψs + O.P
B ψs = T.P
C ψp + ψw
D ψs + ψp
Answer :   ψs + ψp
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450. Genetically dwarf plant can be converted into a plant of normal height with the application of

A Ethylene
B Gibberellins
C Cytokinins
D Auxin
Answer :   Gibberellins
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