Which one of the following statements pertaining to plant structure is correct?
Cork lacks stomata, but lenticels carry out transpiration.
Passage cells help in transfer of food from cortex to phloem
Sieve tube elements possess cytoplasm but no nuclei.
The shoot apical meristem has a quiescent centre
C.
Sieve tube elements possess cytoplasm but no nuclei.
Sieve tubes in flowering plants consists of elongated living cells of the phloem. Their main function is to transport sugars and other important molecules necessary for plants. On maturity, these loose nucleus and other cellular organelles.
Mature cork cells are plant cells that form the protective water resistant tissue in the outer covering of stems and trunks. They are genetically programmed not to divide, but instead to remain as they are dead cells. They also possess lenticels. A lenticel is produced beneath a former stomata or stoma of the epidermis. They encloses intercellular space for gaseous exchange.
Passage cells help in transfer of water from cortex. Quiescent centre is present in root apical meristem.
Assertion: In angiosperms, transport of food and water is more efficient than gymnosperms and pteridophytes.
Reason: In angiosperms longitudinally arranged sieve elements and vessels with perforated end walls are present.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Assertion : In woody stems, the amount of heart wood continues to increase year after year.
Reason : The cambial activity continues uninterrupted.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion : Petroplants produce large amount of latex.
Reason : The latex contains long chain hydrocarbons.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Plasmodesmata connections help in
cytoplasmic streaming
synchronous mitotic divisions
locomotion of unicellular organism
movement of substances between cells
The quiescent centre in root meristem serves as a
site for storage of food which is utilized during maturation
reservoir of growth hormones
reserve for replenishment of damaged cells of the meristem
region for absorption of water
Assertion : Water and mineral uptake by root hairs from the soil occurs through apoplast until it reaches endodermis.
Reason : Casparian strips in endodermis are suberized
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
If both Assertion and Reason are true but the reason is not the correct explanation of the assertion
If Assertion is true statement but Reason is false
If both Assertion and Reason are false statements
In a dicotyledonous stem, the sequence of tissues from the outside to the inside is
phellem - pericycle - endodermis - phloem
phellem - phloem - endodermis - pericycle
phellem - endodermis - pericycle - phloem
pericycle - phellem - endodermis - phloem
When does a plant wilt?
When phloem is blocked
When xylem is blocked
Pith is removed
A few leaves are removed
