Anatomy of Flowering Plants · Question 24

Grass leaves curl inward during very dry weather. Select the most appropriate reason from the following:

1. Shrinkage of air spaces in spongy mesophyll
2. Tyloses in vessels
3. Closure of stomata
4. Flaccidity of bulliform cells

Phloem in gymnosperms lacks:

1. Companion cells only
2. Both sieve tubes and companion cells
3. Albuminous cells and sieve cells
4. Sieve tubes only

Which of the statements given below is not true about formation of Annual Rings in trees?

1. Activity of cambium depends upon variation in climate.
2. Annual rings are not prominent in trees of temperate region.
3. Annual ring is a combination of spring wood and autumn wood produced in a year.
4. Differential activity of cambium causes light and dark bands of tissue – early and late wood respectively

Stomata in grass leaf are

1. kidney-shaped
2. barrel-shaped
3. dumb-bell shaped
4. rectangular

Secondary xylem and phloem in dicot stem are produced by

1. vascular cambium
2. axillary meristems
3. apical meristems
4. phellogen

Casparian strips occur in

1. pericycle
2. epidermis
3. endodermis
4. cortex

Plants having little or no secondary growth are

1. deciduous angiosperms
2. grasses
3. cycads
4. conifers

The vascular cambium normally gives rise to :

1. Primary phloem
2. Secondary xylem
3. Periderm
4. Phelloderm

Which of the following is made up of dead cells ?

1. Collenchyma
2. Xylem parenchyma
3. Phellem
4. Phloem

Identify the wrong statement in context of heartwood :

1. It is highly durable.
2. It comprises dead elements with highly lignified walls
3. It conducts water and minerals efficiently
4. Organic compounds are deposited in it