Which one is true regarding xylem?
1. vessels are absent in gymnosperms
2. cells of vessel are called vessel members
3. tracheid and vessel lack protoplasm
4. All of these
The type of primary xylem when protoxylem lies towards the pith is known as
1. endarch
2. exarch
3. endoexarch
4. Both (1) and (3)
How many elements of the xylem are dead
1. four
2. three
3. two
4. one
Sclerenchymatous fibres are
1. thick walled, elongated and pointed cells
2. contains simple and bordered pits
3. smallest cells in plant body
4. All of these
Secondary growth occurs in
(1)dicot root and stem of angiosperms
(2)dicot root and stem of gymnosperms
(3)monocot roots
(4)Both 1 and 2
Primary xylem remains less or more intact towards the __________
(1) around the centre
(2) around the periphery
(3)outer to the pith
(4)Both A and C
The secondary xylem is produced more because
(1)cambium is more active towards the inner side
(2)cambium is more active towards the outer side
(3)xylem is more important than phloem
(4)All of the above
The cells which are formed from vascular cambium towards the centre are____________and towards the periphery are _________________
(1)secondary xylem, secondary phloem
(2)bast, wood
(3)wood, bast
(4)Both A and C
Secondary growth is because of
1. vascular cambium
2. cork cambium
3. lateral meristem
4. All of the above
Which of the following is true for palisade parenchyma?
1. adaxially placed
2. elongated cells
3. vertically and parallely placed
4. All of the above