431. In the mechanism of opening of stomata, the important factor is

A Turgidity of the guard cells
B Chlorophyll content of the guaed cells
C Hormone content of the subsidiary cells
D Protein content of the epidermal cells
Answer :   Turgidity of the guard cells
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432. Stomata open at day because in day the guard cells have

A To help gas exchange
B A low pH
C Ahigh level of sugar , organic acid ATP & K+ ion
D Unequally thickened walls
Answer :   Ahigh level of sugar , organic acid ATP & K+ ion
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433. A small mesophytic twig with green leaves is dipped in to water in a big beaker under sunlight . It demonstrates

A Photosyntheesis
B Repiration
C Transpiration
D None of the above
Answer :   Transpiration
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434. Before opening of stomata accumulation of the following ion is seen in

A PO4
B K+
C Mg++
D Na+
Answer :   K+
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435. Increase in CO2 concentration around leaf results in

A Rapid opening of stomata
B Partial closure of stomata
C Complete closure of stomata
D No effect on stomatal opening
Answer :   Partial closure of stomata
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436. During rainy season wooden doors generally swell up due to

A Osmosis
B Imbibition
C Bad workmanship
D Wood quality
Answer :   Imbibition
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437. When a plant cell is placed in a hypotonis solution. Which of the following will not apply

A Wall pressure is decreased
B The cell become turgid
C Suction pressure of the cell sap willdecrease
D Water potential of the cell sap will increase
Answer :   Wall pressure is decreased
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438. Active K+ ⇄ H+ exchange theory explained

A Ascent of sap
B Phloem conduction
C Ion abskorption
D Stomatal movement
Answer :   Stomatal movement
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439. Which pigment regulates opening and closing of stomata

A Chlorophylls
B Carotenoids
C Plytochrome
D Flavines
Answer :   Plytochrome
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440. Seeds swell when placed in water due to

A Osmosis
B Imbibition
C Hydrolysis
D All of the above
Answer :   Imbibition
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