In barley stem, vascular bundles are

1. open and scattered

2. closed and scattered

3. open and in a ring

4. closed and radial

Guard cells help in ?

1. protection against grazing

2. transpiration

3. guttation

4. fighting against infection

Palisade parenchyma is absent in leaves of :-

1. Sorghum

2. mustard

3. soybean

4. gram

Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of

1. xerophytes

2. mesophytes

3. epiphytes

4. hydrophytes

Vascular tissues in flowering plants develop from

(1) phellogen

(2) plerome

(3) periblem

(4) dermatogen

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

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

The chief water conducting elements of xylem in gymnosperms are

1. vessels

2. fibres

3. transfusion tissue

4. tracheids

The cork cambium, cork and secondary cortex are collectively called

1. phellogen

2. periderm

3. phellem   

4. phelloderm

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

1. mitochondria

2. endoplasmic reticulum

3. chloroplasts

4. cytoskeleton