Xylem

Q. Unidirectional movement of substances occurs through

1. xylem
2. xylem and phloem
3. phloem
4. None of these

Q. Compare set I with set II and mark the incorrect pairs.

Set I	Set II
i. Xylem	bidirectional
ii. Phloem	unidirectional
iii. Turgidity	outward direction
iv. Wall pressure	inward direction

1. i and ii
2. i, ii and iv
3. iii and iv
4. i, ii and iii

Q. Expalin why xylem transport is unidirectional and phloem transport is bi directional?

Q. Vessel elements are

1. Dead at maturity
2. Are important constituents of all plants
3. Living at maturity
4. All of the above

Q. Which among the following have specialized tissue for conduction of water ?
i. Thallophyta
ii. Bryophyta
iii. Pteridophyta
iv. Gymnosperms

1. ii and iii
2. i and iv
3. iii and iv
4. i and ii

Q. Explain why xylem transport is unidirectional and phloem transport bidirectional.

Q. The principal pathway of water translocation in angiosperms is

1. Sieve cells
2. Sieve tube elements
3. Xylem vessel system
4. Xylem and phloem

Q. If in a tree, a cut end is put in eosin solution then

1. Leaves remain fresh but ascent of sap stops.
2. Leaves will quickly die because ascent of sap stops.
3. Phloem gets coloured because of ascent of sap.
4. Xylem elements get stained showing ascent of sap through them.

Q. Bordered pits relating with water uptake are located in

1. Vessel element
2. Cortex
3. Endodermis
4. Tracheary elements

Q. What would be the effect if a freshly cut end of a plant is put in eosin solution?

1. Phloem gets colored because of ascent of sap
2. Xylem elements get stained showing ascent of sap through them
3. Leaves remain fresh but ascent of sap stops
4. Ascent of sap stops