Q. No.Transport of food material in higher plants takes place through:
1. Transfusion tissue
2. Tracheids
3. Sieve elements
4. Companion cells
Given below is the diagram of a stomatal apparatus. In which of the following, all the four parts labelled as A, B, C and D are correctly identified:
| A | B | C | D | |
| 1. | Guard cell | Stomatal aperture | Subsidiary Cell | Epidermal Cell |
| 2. | Epidermal Cell | Guard Cell | Stomatal aperture | Subsidiary cell |
| 3. | Epidermal Cell | Subsidiary Cell | Stomatal aperture | Guard Cell |
| 4. | Subsidiary Cell | Epidermal Cell | Guard Cell | Stomatal aperture |
Some vascular bundles are described as open because these:
| 1. | are not surrounded by pericycle |
| 2. | are surrounded by pericycle but no endodermis |
| 3. | are capable of producing secondary xylem and phloem |
| 4. | possess conjunctive tissue between xylem and phloem |
Compared to a dicot root, a monocot root has:
1. Many xylem bundles
2. Inconspicuous annual rings
3. Relatively thicker periderm
4. More abundant secondary xylem
| 1. | Guard cells invariably possess chloroplasts and mitochondria |
| 2. | Guard cells are always surrounded by subsidiary cells |
| 3. | Stomata are involved in gaseous exchange |
| 4. | Inner walls of guard cells are thick |
A common structural feature of vessel elements and sieve tube elements is:
1. thick secondary walls
2. pores on lateral walls
3. presence of P-protein
4. enucleate condition
Passage cells are thin-walled cells found in:
| 1. | endodermis of roots facilitating rapid transport of water from cortex to pericycle |
| 2. | phloem elements that serve as entry points for substances for transport to other plant parts |
| 3. | testa of seeds to enable emergence of growing embryonic axis during seed germination |
| 4. | central region of style through which the pollen tube grows towards the ovary |
Guard cells help in:
1. protection against grazing
2. transpiration
3. guttation
4. fighting against infection
Anatomically, fairly old dicotyledonous root is distinguished from the dicotyledonous stem by:
1. absence of secondary xylem
2. absence of secondary phloem
3. presence of cortex
4. position of protoxylem
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