Assertion : Long distance flow of photoassimilates in plants occurs through sieve tubes.
Reason : Mature sieve tubes have parietal cytoplasm and perforated sieve plates.
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
A.
If both Assertion and Reason are true and the reason is the correct explanation of the assertion
The main function of sieve tube is the transport of food products from green and storage organs of the plant to other organs of the plant. The sieve clements are sieve tubes arranged one above the other and have sieve plates (obligue or transverse perforated septa) on their end walls. The cytoplasm occur in the form of a thin living layer along the inner side of cellulose wall. The nucleus disappears in mature sieve elements.
Ectophloic siphonostele is found in
Osmunda and Equisetum
Marsilea and Botrychium
Adiantum and Cucurbitaceae
Dicksonia and Maiden hair fern
The plant undergoes wilting when
xylem is blocked
cambium is blocked
phloem is blocked
some roots are reduced in number
Assertion: In angiosperms the conduction of water is more efficient because their xylem has vessels.
Reason: Conduction of water by vessel elements is an active process with energy supplied by xylem parenchyma rich in mitochondria
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.
