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प्रश्न
Water molecule is very polar. Polar end of molecule attracts opposite charges on another water molecule (acts like magnet). How will you explain this property of water with reference to upward movement of water? Comment on the upward movement of water given the intermolecular hydrogen bonding in water.
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उत्तर
Water molecules are polar. There is a formation of hydrogen bonds between slightly negative and slightly positive charged oxygen and hydrogen bonds respectively when the two water molecules approach each other. The surface tension of the liquid is one of the principal factors of attractive force along with other intermolecular forces. It also helps in dragging water from the xylem to the leaf
Cohesion between water molecules helps in making a continuous column of water in the xylem. This, along with adhesion and surface tension, helps the transpiration pull to pull up the water column in plants. Thus, a multitude of factors is working during the ascent of sap in plants.
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संबंधित प्रश्न
Discuss the factors responsible for ascent of xylem sap in plants
What are stomata?
The loss of water in the form of water vapour through stomata on leaves is known as ___________.
Why is there a need for a transport system in plants and animals?
Give suitable explanation for the following:
On a bright sunny day, the leaves of certain plants roll up.
Given below is a diagrammatic sketch (surface view) of a stomatal apparatus from a dicot leaf.
(a) Label the parts numbers 1-3
(b) Is this state, open or closed?
(c) Is this stoma, of a dicot leaf or a monocot leaf?
(d) Redraw a sketch of the stomatal apparatus in the state opposite to the one shown here.
Given alongside is the diagram of an experimental set-up to demonstrate a certain phenomenon in plants.
Name the phenomenon being demonstrated.
Give a reason.
What happens to the movement of the air-bubble if the apparatus shown above is kept in dark.
The figure below represents the set-up at the start of certain experiment to demonstrate an activity of plants:
(i) What is the aim of the experiment?
(ii) Why has oil been put in each test tube?
(iii) What will be the observations in the two test-tubes after about 2-3 days?
(iv) Give reasons to explain any change observed as answered in (iii) above.
(v) Why has the test-tube b without the plant, been taken in the experiment?
An apparatus as shown below was set up to investigate a physiological process in plants. The setup was kept in sunlight for two hours. Droplets of water were then seen inside the bell jar. Answer the questions that follow:
Suggest a suitable control for this experiment.
Design an experiment to demonstrate the transpiration process.
During transpiration, there is a loss of ______
Transpiration is a necessary evil in plants. Explain.
Boojho’s uncle was hospitalised and put on dialysis after a severe infection in both of his kidneys.
What is dialysis?
Write a note on Transpiration.
Do different species of plants growing in the same area show the same rate of transpiration at a particular time? Justify your answer.
ABA (Abscisic acid) is called a stress hormone. From where does this hormone get released in leaves?
A root hair is derived from ______ cell.
Enlist different advantages of transpiration.
