Q30 / 180 · NEET 2015 (Phase 1) · Botany

Transpiration and root pressure cause water to rise in plants by:

  • A
    Pulling it upward
  • Correct answer
    B
    Pulling and pushing it, respectively
  • C
    Pushing it upward
  • D
    Pushing and pulling it, respectively

Solution

In transpiration water rises in plant due to strong cohesive force of transpiration pull in which water is pulled (absorbed) from soil to roots, roots to stem, stem to xylem of leaf and lastly xylem to vein of leaf which is then evaporated. Whereas, root pressure causes passive absorption of water resulting in rise of water in plants i.e. it creates tension in xylem elements which is transmitted downwards up to the root hair, as a result roots are subjected to tension and suction is set up in xylem; hence water is pulled inside the roots.

Hence, the correct answer is option: 'B'.

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