1. Tardigrade
  2. Question
  3. Biology
  4. Read the following statements: Statement A: Ascent of sap is a passive activity driven by transpiration pull. Statement B: During day time, stomata open due to respiratory activity.

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Q. Read the following statements:
Statement A: Ascent of sap is a passive activity driven by transpiration pull.
Statement B: During day time, stomata open due to respiratory activity.

KCETKCET 2022

Solution:

Transpiration occurring in the leaves is the major phenomena that results in the upward conduction of sap in xylem that creates transpiration pull. According to Transpiration pull theory, the cohesive and adhesive properties of water results in the formation of a continuous unbroken column of water in the xylem vessel elements. This is pulled upwards due to transpiration pull. On the other hand, the stomata opens during day time due to the photosynthetic utilization of $CO_2$ in the guard cells, that result in various activities and finally endosmosis occur in guard cells. Opening of stomata results in transpiration.