Question 6: Distinguish between the following:
a. Exarch and endarch
b. Stele and vascular bundle
c. Protoxylem and metaxylem
d. Interfasicular cambium and intrafasicular cambium
e. Open and closed vascular bundles
f. Stem hair and root hair
Answer:
a. Exarch: When the protoxylem is present towards the periphery and metaxylem is present towards the center.
Endarch: When the protoxylem is present towards the center and the metaxylem towards the periphery.
b. Stele: Stele is the central part of the root or stems.
Vascular bundle: Vascular bundle is the part of stele.
c. Protoxylem: The xylem that formed earlier is known as Protoxylem.
Metaxylem: The xylem that formed later is metaxylem.
d. Interfascicular cambium: It is present between the primary xylem and primary phloem.
Intrafascicular: It is present in between the two vascular bundles.
e. Open vascular bundles: A vascular bundle which is capable secondary growth.
Closed vascular bundles: A vascular bundle which is not capable of secondary growth.
f. Stem hair: 1. These are multicellular.
2. Function is to increase the surface for absorption.
Root hair: 1. These are unicellular.
2. Function is to prevent water loss.
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