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प्रश्न
What are the limitations of root pressure theory?
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उत्तर
Although the ascent of sap takes place due to root pressure, there are certain objections raised, such as:
- It is not applicable to plants taller than 20 meters.
- Ascent of sap can also occur even in the absence of a root system.
- The root pressure value is almost nearly zero in taller gymnosperm trees.
- In actively transpiring plants, no root pressure is developed.
- Xylem sap under normal conditions is under tension, i.e., it shows negative hydrostatic pressure or high osmotic pressure.
Thus, root pressure is not the sole mechanism explaining the ascent of sap in all plants of varying heights.
संबंधित प्रश्न
Very short answer question.
Why do diurnal changes occur in osmotic potential of guard cells?
Explain the root pressure theory.
Why is transpiration is called ‘a necessary evil’?
Answer the following question.
What is the significance of transpiration?
Which of the following term correctly describes the membrane which allows passage of certain substances more readily than others?
Give an example of plant having both kidney and dumb-bell shaped guard cells in stomata.
Sketch and label - structure of stomata[ apparatus.
Sketch and label:
Types of guard cells
In plants, active absorption usually does NOT occur when ______.
Statement I - During night, guard cells become flaccid.
Statement II - During day time, guard cells become turgid due to endosmosis.
In light of above statements, choose the most appropriate answer from the option given below.
