Tag: botany

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Questions Related to botany

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

Active K$^+$ mechanism of opening and closing of the stomata was given by

  1. Darwin

  2. Leuitt

  3. Scarth

  4. Khorana
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  • Potassium is a very important macronutrient for plants. Its ions cause the turgor movement of guard cells. 
  • The gain of potassium ions by the guard cells causes a decrease in water potential of guard cells. 
  • This makes guard cells turgid and hence they swell. Increase in turgidity of guard cells opens the stomatal pore. 
  • Movement of potassium ions from the guard cells results in the increase of water potential. It becomes flaccid and stomatal pore closes. This mechanism of stomatal opening and closing was first stated by Levitt.

The correct option is B.

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

According to sugar concentration theory, during daytime guard cells become

  1. Turgid

  2. Flaccid

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to sugar concentration theory,during daytime ,the guard cells begin photosynthesis and the sugar produced during the process increases the osmotic pressure which draws in water from the adjoining cells due to endosmosis.

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

According to sugar concentration theory, during daytime water is drawn from adjoining cells due to

  1. Endosmosis

  2. Exosmosis

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to sugar concentration theory,during daytime ,the guard cells begin photosynthesis and the sugar produced during the process increases the osmotic pressure which draws in water from the adjoining cells due to endosmosis.

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

According to sugar concentration theory, during ............, the guard cells begin photosynthesis.

  1. Night

  2. Daytime

  3. Both A and B

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to the sugar concentration theory, during the daytime, the guard cells do photosynthesis. And the sugar is produced during the process and it increases the osmotic pressure which draws in the water from the adjoining cells due to endosmosis.

So the correct option is Daytime.

The correct option is B.

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

According to the sugar concentration theory, during daytime the guard cells become

  1. Turgid.

  2. Flaccid.

  3. Placid.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
During day time, photosynthesis occur in the guard cells and glucose is produced. Creating an osmotic gradient, resulting in movement of water from adjacent cells into the guard cells making them turgid.
So, the correct answer is 'Turgid'
Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

Who explained the scotoactive opening of stomata?

  1. Nishida

  2. Palls

  3. Ehrler

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Some stomata open during night and remain closed during the day time. This type of stomatal is called scotoactive stomata. They occur in succulents e.g., Cactus, Bryophyllum. This mechanism was explained by Nishida (1963).

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

Porometer was developed by :

  1. Darwin

  2. Freeman

  3. Livingston

  4. Ganong
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Porometer is an instrument for measuring the area of the stomatal openings of a leaf by the amount of a gas passing through a given area of it. The porometer was first described as a method for investigating stomatal movement by Darwin.

Multiple choice botany transport in plant homeostasis in plants regulation of stomatal opening stomata

Which growth hormone is associated with stomatal movements?

  1. Auxin

  2. ABA

  3. Gibberellin

  4. Cytokinin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

ABA is known to have a direct effect on the movement of stomata. When ABA is present, it does not allow the uptake of potassium ions which help in the opening of stomata and hence the pore closes.

Effect of ABA is countered by hormones Auxin and Cytokinin.
Gibberellins have a major contribution to cell elongation and growth.
So the correct answer is 'ABA'.