AIIMS 2006
- Exam
- AIIMS
- Year
- 2006
- Subject
- Botany
- Chapter
- Transport in Plants
AIIMS 2006 · Botany · Transport in Plants
Assertion : When the ambient temperature is high and soil contains...
Assertion : When the ambient temperature is high and soil contains excess of water, the plants tend to lose water in the form of droplets from lenticels.
Reason : Root pressure regulates the rate of loss of water form lenticels.
Options
- AIf both assertion and reason are true and reason is the correct explanation of the assertion
- BIf both assertion and reason are true but reason is not the correct explanation of the assertion
- CIf assertion is true, but reason is false
- DBoth assertion and reason are false statements.
Correct answer
D. Both assertion and reason are false statements.
Step-by-step solution
When the ambient temperature is high and soil contains excess water, the rate of transpiration is increased i.e., loss of water takes place from leaves through stomata. Lenticular transpiration is only of the total transpiration. It however continues day and night because lenticels have no mechanism of closure. The lenticels connect the atmospheric air with the cortical tissue of stem through intercellular spaces present amongst the complementary cells. Root pressure regulates the rate of loss of water from the stomata in some plants. High temperature may cause desiccation and closure of stomata. Root pressure is a positive pressure that develops in the xylem sap of the roots of some plants.