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Question
Mark the most appropriate answer in the following:
In the mechanism of opening and closing of stomata, the important factor is
Options
The presence of chloroplast in the guard cells
The turgid and flaccid state of the guard cells
The protein content of the cells
The starch content of the cells
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Solution
The turgid and flaccid state of the guard cells
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RELATED QUESTIONS
Name the following:
Any two parts of a leaf which allow transpiration.
Choose the correct answer:
Stomata can open in night also in _______________
State the functions of guard cells.
The figure below represents the vertical section of a leaf:
(i) Name the parts labeled 1 to 5.
(ii) What do the two arrows (dotted and solid) indicate in the day time and at night?
(iii) Could you add one more arrow in the figure? If yes, what for?
(iv) How many leaf veins have been shown in this section?
Given below is the diagram of an experimental set up to study the process of transpiration in plants. Study the same and then answer the questions that follow:
(i) What is the colour of dry cobalt chloride paper?
(ii) Is the experimental leaf a monocot or a dicot? Give a reason to support your answer.
(iii) Why axe glass slides placed over the dry cobalt chloride papers?
(iv) After about half an hour what change, if any, would you expect to find in the cobalt chloride paper placed on the dorsal and ventral sides of the leaf? Give a reason to support your answer.
(v) Define the term ‘transpiration’.
Give Technical Term
Opening found on the undersurface of the dorsiventral leaf.
Guard cells help in regulating the ______.
Assertion (A): The loss of excess water from the aerial parts of the plant in the form of water vapor is known as transpiration.
Reason (R): Stomata of the leaf perform transpiration.
The given figure represents an experiment:
- Leaf A was coated with grease on both surfaces.
- Leaf B was coated with grease on the lower surface.
- Leaf C was coated with grease on the upper surface.
- Leaf D was left without any application of grease. All four leaves A, B, C and D were left in a room for about 24 hours.
- Which leaf dries first? Give reason.
- Which leaf dries last? Give reason.
Given below is the figure of a stoma. Study the same and answer the following questions:
- Label the guidelines A and B.
- Write the exact location of the above-mentioned structures.
- Mention one important role of structure A.
- Write three important roles for structure B.
- Redraw the same figure when structures A are in flaccid condition. When does the flaccid condition occur?
