Multiple Choice QuestionsMost accepted theory for ascent of sap is
capillary theory
root pressure theory
pulsation theory
transpiration pull
D.
transpiration pull
Transpiration pull or the suction force is the force which aids in drawing the water upward from roots to leaves. In leaves, some amount of water is used for photsynthesis and excess of water is released into atmosphere through openings called as stomata.
Root Pressure Theory is the transverse osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves.
Pulsation theory or Vital force theory was not accepted because living cells are not involved in the ascent of sap as water continue to rise upwards in the plant.
Capillarity Theory is the capillarity movement of water due to adhesion and cohesion forces balanced by downward pull of gravity.
Which of the following is not the feature of gymnosperms?
parallel venation
perennial plants
distinct branches (long and short branches)
xylem with vessels
Which of the following is/ are grouped under phanerogams?
Angiosperms
Gymnosperms
Pteridophytes
Both (a) and (b)
Which of the following theory gives the latest explanation for the closure of stomata?
ABA theory
Munch Theory
Starch glucose theory
Active K+ transport theory
The trisomy for 21st chromosome is called
Down's syndrome
Turner's syndrome
Sickle cell anaemia
Klinfelter's syndrome
Which is correctly matched?
Apiculture - Honey bee
Pisciculture - Silk moth
Sericulture - Fish
Aquaculture - Mosquito
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