Biology

Plant Transport and Physiology

1,834 Questions

Access a comprehensive set of questions on plant transport mechanisms and physiological adaptations. Topics include water movement, translocation of food, and plant responses to external stimuli. These biology questions are essential for medical entrance exams and other science competitive tests.

Xylem and phloem transportTranspiration and evaporationPlant adaptationsGeotropic and phototropic responsesWater absorption by rootsRespiration in roots

Plant Transport and Physiology Questions

Multiple choice

Which among the following statements does NOT characterizes phloem tissues in plants?

  1. The sieve-tube cells are deficit of a prominent nucleus and a distinct vacuole and lies on the outside of the xylem.

  2. Hydrostatic pressure refers to the pressure that any fluid in a confined space exerts. The movement through the phloem is compelled by positive hydrostatic pressures.

  3. Messenger RNA is a subtype of RNA. Sieve tube elements are carries messenger RNAs in the phloem.

  4. Phloem sap is composed largely of sugar dissolved in water and it aids in conducting informational signals throughout vascular plants.

  5. When the plant is an embryo, vascular tissue originates from cambium tissue.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This one is the incorrect statement as when the plant is an embryo, vascular tissue emerges from procambium tissue, which is at the center of the embryo. Protophloem itself appears in the mid-vein extending into the cotyledonary node, which constitutes the first appearance of a leaf in angiosperms, where it forms continuous strands.

Multiple choice

Most of the transpiration which takes place in plants is called

  1. cuticular transpiration

  2. lenticular transpiration

  3. foliar transpiration

  4. cauline transpiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The loss of water which takes place from leaves is called foliar transpiration. Most of the (80-90%) transpiration which takes place in plants is foliar transpiration.

Multiple choice

Which of the following statements are untrue?

  1. Transpiration is regulated by guard cells.

  2. Transpiration stops when air is fully saturated.

  3. Transpiration is dependent upon absorption of water from the soil.

  4. Transpiration takes place from aerial parts of the plant.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is untrue. Transpiration continues for some time even after saturation of outside air.

Multiple choice

Lenticular transpiration takes place through

  1. flowers

  2. tendrils

  3. fruits

  4. green stems
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Lenticular transpiration takes place through fruits. This type of transpiration continues day and night because lenticels have no mechanism of closure.

Multiple choice

Transpiration is reduced when

  1. atmospheric pressure is lowered

  2. soil contains higher concentration of salts

  3. abundant light is present

  4. atmosphere is less humid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Higher concentration of salts in soil reduces the absorption rate, thereby, reducing the rate of transpiration.

Multiple choice

Stomata opens wide when

  1. atmosphere outside the stomata is less saturated

  2. secretion of salt molecules by the adjacent guard cells takes place

  3. water molecules enter the guard cells

  4. there is sudden fall of temperature
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stomata widely opens when water molecules enter the guard cells and becomes turgid.

Multiple choice

Cobalt chloride experiment is used

  1. to demonstrate the process of transpiration

  2. to determine the rate of transpiration

  3. to show that the rate of transpiration from the lower surface of leaf is higher than the upper surface

  4. to demonstrate the phenomenon of osmosis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cobalt chloride method is used to show that the rate of transpiration from the lower surface of leaf is higher than the upper surface.

Multiple choice

According to Von Mohl,

  1. starch to sugar inter-conversion regulates stomatal opening or closing

  2. osmotic pressure regulates the stomatal opening and closing

  3. opening and closing of stomata takes place by an active transport of K+ ions into the guard cells

  4. transpiration pull regulates stomatal opening or closing
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

According to Von Mohl, Osmotic pressure regulates the stomatal opening and closing.