Statement I: | Parenchyma is living but collenchyma is dead tissue. |
Statement II: | Gymnosperms lack xylem vessels but presence of xylem vessels is the characteristic of angiosperms. |
A. | Companion cells help in maintaining the pressure gradient in the sieve tubes. |
B. | Gymnosperms lack vessels in their xylem |
C. | The xylem vessels are devoid of cytoplasm |
D. | Xylem fibres may be septate or aseptate |
E. | A mature sieve element in phloem possesses cytoplasm, vacuole and nucleus. |
The chief water conducting elements of xylem in gymnosperms are:
1. vessels
2. fibres
3. transfusion tissue
4. tracheids
Vessels are found in:
1. | All angiosperms and some gymnosperm |
2. | Most of the angiosperm and few gymnosperms |
3. | All angiosperms, all gymnosperms, and some Pteridophyta |
4. | All pteridophyta |