Most 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.
The most important force which pulls water up in tall trees is
imbibition force
osmotic force
cohesive force
electromagnetic force
Transpiration would be lowest when
wind velocity is high
enough water is in the soil
atmospheric RH is high
high temperature and light
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 light phase of photosynthesis is called
Hill reaction
photo action
pigment action
chlorophyllous process
Which of the following exhibits a direct porportionality to transpiration
Light and RH
Temperature and RH
Temperature and wind
RH and wind
