Transpiration (Multiple Choice Questions and Answers)


Multiple Choice Questions and Answers

1. The metal ion involved in stomatal regulation is

(a) iron

(b) magnesium

(c) zinc

(d) potassium

Answer: (d) potassium

2. Increase in CO2 concentration around leaf causes

(a) rapid opening of stomata

(b) partial closure of stomata

(c) complete closure of stomata

(d) there will be no effect on stomatal opening

Answer: (c) complete closure of stomata

3. Transpiration occurs from

(a) leaves

(b) stems

(c) all aerial parts

(d) roots

Answer: (c) all aerial parts

4. What percentage of water absorbed by herbaceous plants is lost during transpiration?

(a) 80

(b) 60

(c) 90

(d) 40

Answer: (c) 90

5. Stomata open during the daytime because the guard cells

(a) photosynthesize and produce osmotically active sugars

(b) are thin walled

(c) are bean shaped

(d) have to help in gaseous exchange

Answer: (a) photosynthesize and produce osmotically active sugars

6. In which of the following plants would metabolism be hindered if the leaves are coated with wax on their upper surface

(a) Hydrilla

(b) Lotus

(c) Pistia

(d) Vallisneria

Answer: (b) Lotus

7. Active potassium ions exchange mechanism for opening and closing of stomata was given by

(a) Darwin

(b) Levitt

(c) Scarth

(d) Khorana

Answer: (b) Levitt

8. On a wind less hot day, one would perspire more in a thick forest because

(a) heat is created by respiration of plants

(b) plants transpire

(c) comparatively less light falls in the forest

(d) it is only a psychological reason

Answer: (b) plants transpire

9. Of the processes which occurs in leaves, the one which may lower their temperature is

(a) respiration

(b) photosynthesis

(c) transpiration

(d) hydrolysis

Answer: (c) transpiration

10. Which is the action spectrum of transpiration?

(a) green and ultraviolet

(b) orange and red

(c) blue and far red

(d) blue and red

Answer: (d) blue and red

11. Water of guttation is

(a) pure water

(b) water with dissolved salts

(c) solution of organic food

(d) condensed water vapour

Answer: (b) water with dissolved salts

12. The actual amount of moisture retained by the air is called

(a) absolute humidity

(b) positive humidity

(c) relative humidity

(d) differential humidity

Answer: (c) relative humidity

13. The conditions under which transpiration would be most rapid

(a) high humidity

(b) excess of water in the soil

(c) low humidity and high temperature

(d) low wind velocity

Answer: (c) low humidity and high temperature

14. If the stomata more on the under surface of the leaves than on upper, it comes under

(a) Oat type

(b) Barley type

(c) Potato type

(d) Potamogeton type

Answer: (c) Potato type

15. Which of the following is used to determine the rate of transpiration in plants?

(a) porometer

(b) potometer

(c) auxanometer

(d) photometer

Answer: (b) potometer

16. Wilting of plants result from excessive

(a) respiration

(b) photosynthesis

(c) absorption

(d) transpiration

Answer: (d) transpiration

17. In many thin leaved mesophytes, stomata open during day and close at night. This comes under

(a) Barley type

(b) Potato type

(c) Alphalpha type

(d) Bean type

Answer: (c) Alphalpha type

18. Generally, the number of stomata per square centimetre leaf area is

(a) in millions

(b) less than 100

(c) in thousands

(d) none of the above

Answer: (c) in thousands

19. The plants die due to wilting when

(a) available light is reduced to half

(b) xylem is blocked

(c) a few roots are broken

(d) phloem is blocked

Answer: (b) xylem is blocked

20. Conversion of starch to organic acid is essential for stomatal

(a) closure

(b) opening

(c) initiation

(d) growth

Answer: (b) opening

21. The process of the escape of liquid from the tip of injured leaf is called

(a) evaporation

(b) transpiration

(c) guttation

(d) evapo-transpiration

Answer: (c) guttation

22. Which of the following is produced during water stress and causes closure of stomata?

(a) cytokinin

(b) auxin

(c) GA3

(d) ABA

Answer: (d) ABA

23. Phenyl mercuric acetate

(a) reduces transpiration

(b) reduces photosynthesis

(c) decreases water absorption

(d) kills the plant

Answer: (a) reduces transpiration

24. The rate of transpiration is dependent upon

(a) negative root pressure

(b) temperature

(c) DPD

(d) vapour pressure deficit

Answer: (d) vapour pressure deficit

25. A specialised multicellular structure in leaves which excretes water droplets is

(a) lenticels

(b) stomata

(c) hydathode

(d) bordered pit

Answer: (c) hydathode

26. Increase in the CO2 concentration of micro environment of leaf would cause

(a) closure of stomata

(b) opening of stomata

(c) no effect on stomata

(d) wider opening of stomata

Answer: (a) closure of stomata

27. Process of water exudation through hydathodes is called

(a) guttation

(b) transpiration

(c) excretion

(d) hydrolysis

Answer: (a) guttation

28. Which one of the following factors is the most important the regulation of transpiration?

(a) humidity

(b) light

(c) temperature

(d) wind

Answer: (a) humidity

29. In old trees or woody plants transpiration occurs through

(a) stomata

(b) bark

(c) lenticels

(d) root

Answer: (c) lenticels

30. In the process of transpiration the water from ground to the root moves due to

(a) osmosis

(b) imbibition

(c) transpiration pull

(d) plasmolysis

Answer: (a) osmosis

31. In a hot sunny day water in plants is

(a) pushed up

(b) pulled up

(c) sucked up

(d) all of the above

Answer: (b) pulled up

32. Mid-day closure of stomata is due to

(a) maximum rate of photosynthesis

(b) fatigue

(c) high wind velocity

(d) excessive transpiration

Answer: (d) excessive transpiration

33. Stomata are widespread in plant Kingdom accept

(a) algae and fungi

(b) angiosperms and gymnosperms

(c) cycads and ferns

(d) horse tails and mosses

Answer: (a) algae and fungi

34. What is the action spectrum of transpiration?

(a) orange and red

(b) blue and red

(c) green and UV

(d) blue and far red

Answer: (b) blue and red

35. Basis of stomatal opening is

(a) decrease in cell sap concentration

(b) plasma lies of guard cells

(c) endosmosis

(d) exosmosis

Answer: (c) endosmosis

36. The stomatal transpiration almost completely stops at

(a) night

(b) noon

(c) in the morning

(d) in the evening

Answer: (a) night

37. The magnitude of water loss as a result of transpiration will be greater when

(a) leaf area is greater

(b) there is increase in temperature

(c) there is increase in wind velocity

(d) all of the above

Answer: (d) all of the above

38. The cause of guttation is

(a) transpiration

(b) higher leaf temperature

(c) higher root pressure

(d) obstructed xylem elements

Answer: (c) higher root pressure

39. Stomata can open at night also in

(a) xerophytes

(b) gametophytes

(c) hydrophytes

(d) none of these

Answer: (a) xerophytes

40. Who had said that ‘transpiration is a necessary evil’?

(a) Curtis

(b) Steward

(c) Anderson

(d) J C Bose

Answer: (a) Curtis

41. Wilting of plants occurs due to

(a) root pressure

(b) transpiration

(c) guttation

(d) DPD

Answer: (b) transpiration

42. Which of the following helps in opening of stomata?

(a) potassium ions

(b) calcium ions

(c) hydrogen ions

(d) chloride ions

Answer: (a) potassium ions

43. Guttation occurs when plants absorb water by

(a) active absorption

(b) passive absorption

(c) root pressure

(d) both a and b

Answer: (c) root pressure

44. The internal factor for transpiration is

(a) oxygen

(b) carbon dioxide

(c) nitrogen

(d) sunken stomata

Answer: (d) sunken stomata

45. Stomata of a plant open due to

(a) influx of potassium ions

(b) efflux of potassium ions

(c) influx of hydrogen ions

(d) influx of calcium ions

Answer: (a) influx of potassium ions

46. What does not cause stomatal opening?

(a) circadian rhythm

(b) influx of potassium ions

(c) light

(d) high carbon dioxide concentration

Answer: (d) high carbon dioxide concentration

47. Transpiration is mainly a process of

(a) imbibition

(b) respiration

(c) osmotic pressure

(d) diffusion

Answer: (d) diffusion

48. Which ones did not show transpiration?

(a) aquatic plants with floating leaves

(b) aquatic submerged plants

(c) plants growing in hilly areas

(d) plants living in desert

Answer: (b) aquatic submerged plants

49. Oozing out of water drops from injured edges or tips is

(a) bleeding

(b) guttation

(c) transpiration

(d) oozation

Answer: (a) bleeding

50. Conversion of starch to ……. is essential for stomatal regulation

(a) protein

(b) organic acid

(c) fat

(d) alcohol

Answer: (b) organic acid