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प्रश्न
ABA (Abscisic acid) is called a stress hormone. How does this hormone overcome stress conditions?
उत्तर
Abscisic acid is a stress hormone and during stress conditions, it induces changes like the closing of stomata to prevent further water loss during the scarcity of water, aids in seed germination when conditions are favourable and dormancy when not and other changes as and when required.
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संबंधित प्रश्न
What causes the opening and closing of guard cells of stomata during transpiration?
Which of the following helps in the upward movement of water and dissolved minerals from the roots to the leaves through the stem?
State whether the following statement is true or false. Rewrite the false statement correctly.
Transpiration cools the plant when it is hot outside.
Define the three processes by which plants absorb water and minerals from the soil.
Give suitable explanation for the following:
Cork and bark of trees help in preventing loss of water
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.
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?
Give Technical Term
When cobalt chloride paper is placed on lower and upper surface of the leaf, the paper of which side becomes more pink?
Entry of water into root hair is the demonstration of which of the following process?
Will the ascent of sap be possible without the cohesion and adhesion of the water molecules? Explain.
