Q41
Age of a tree can be estimated by :
Correct Answer
Option B
Solution
Age of a tree can be estimated by number of annual rings.
Annual ring constitute alternate concentric rings of spring wood and autumn wood.
Anatomy of Flowering Plants
Q42
As compared to a dicot root, a monocot root has
Correct Answer
Option C
Solution
The vascular bundles are arranged in a loose circle inside the endodermis of a monocot root.
In a monocot root, more than six vascular bundles are present.
It shows polyarch condition.
Q43
The common bottle cork is a product of
Correct Answer
Option A
Solution
The common bottle cork is the product of phellogen.
Phellogen produces cork or phellem on the outer side.
It consists of dead and compactly arranged rectangular cells that possess suberised cell walls.
The cork cells contain tannins.
Hence, they appear brown or dark brown in colour.
The cork cells of some plants are filled with air e.g., Quercus suber (Cork Oak or Bottle Cork).
Q44
Water containing cavities in vascular bundles are found in
Correct Answer
Option A
Solution
Stem of maize has water containing cavities in vascular bundles.
Q45
Companion cells are closely associated with
Correct Answer
Option A
Solution
Companion cell is a type of cell found within the phloem of flowering plants.
Each companion cell is usually closely associated with a sieve element.
They remain connected with sieve cells by plasmodesmata.
They help in loading of phloem sieve cells with sugars through active transport.
Q46
Gymnosperms are also called soft wood spermatophytes because they lack
Correct Answer
Option D
Solution
Xylem fibres provide rigidity to the plant.
Q47
Closed vascular bundles lack
Correct Answer
Option C
Solution
Vascular bundle consists of complex tissues, the phloem and xylem.
In dicots, between xylem and phloem, cambium is present which helps in secondary growth.
This type of vascular bundle is called open.
While in monocots cambium is absent, so these are called closed vascular bundles.
Q48
Function of companion cells is :
Correct Answer
Option B
Solution
Companion cells move sugar and amino acids into and out of the sieve elements.
In source tissue such as leaf companion cells use transmembrane proteins to take up sugar and amino acids by active transport.
Movement of sugars in the phloem begins at the source, where sugars are loaded (actively transported) into a seive tube.
Loading sets up a water potential gradient that facilitates movement of sugar.
Q49
Some vascular bundles are described as open because these :
Correct Answer
Option A
Solution
In dicot stem, cambium is present between xylem and phloem, such vascular bundles are called open.
In monocot stem, the cambium is absent, such vascular bundles are called closed.
Cambium are the meristematic cells which produces secondary xylem and phloem.
Q50
Ground tissue includes :
Correct Answer
Option D
Solution
Ground tissue includes all tissues except epidermis and vascular bundles.
The ground tissue comprises the bulk of the primary plant body.
Parenchyma, collenchyma and sclerenchyma cells are common in the ground tissue.
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