Companion cells are closely associated with

(1) sieve elements

(2) vessel elements

(3) trichomes

(4) guard cells

Closed vascular bundles lack

1. ground tissue

2. conjunctive tissue

3. cambium

4. pith

Water containing cavities in vascular bundles are found in

1. sunflower
2. maize
3. Cycas
4. Pinus

Ground tissues includes

In land plants, the guard cells differ from other epidermal cells in having:-

1. mitochondria

2. endoplasmic reticulum

3. chloroplasts

4. cytoskeleton

The cork cambium, cork and secondary cortex are collectively called

1. phellogen

2. periderm

3. phellem   

4. phelloderm

The chief water conducting elements of xylem in gymnosperms are

1. vessels

2. fibres

3. transfusion tissue

4. tracheids

Which one of the following is not a lateral meristem?

1. Cork cambium

2. Interfascicular cambium

3. Phellogen

4. Intercalary meristem

Heartwood differs from sapwood in 

1. presence of rays and fibres

2. absence of vessels and parenchyma

3. having dead and non-conducting elements

4. being susceptible to pests and pathogens

In barley stem, vascular bundles are

1. open and scattered

2. closed and scattered

3. open and in a ring

4. closed and radial