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

The annular and spirally thickened conducting elements generally develop in the

protoxylem when the root or stem is

1. maturing

2. elongating

3. widening

4. differentiating

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

For a critical study of secondary growth in plants, which one of the following pairs is

suitable:

1. Sugarcane and sunflower

2. Teak and pine

3. Deodar and fern

4. Wheat and maiden hair fern

If the stoma remains surrounded by a limited number of cells which cannot be

distinguished from other epidermal cells, then this type of stomata is known as.

1. perigynous type

2. paracytic type

3. anisocytic type

4. anomocytic type