Vessels are elongated, multicellular water conducting channels with wide lumen formed by end to end fusion of a large number of vessel elements.
Tracheids are elongated dead cells with tapering ends having lignified walls and large or wide lumen.
Their main function is conduction of water and minerals from root to leaf.
Generally gymnosperms do not have vessels but a few gymnosperms with vessels are Ephedra, Smilax etc.
Most of angiosperms have vessels except of few e.g., Trochodendron.
Apical meristems are situated at the tips of the root and shoot.
They take part in initial growth.
Plants elongate and increase in height as a result of divisions in this meristem.
Promeristem and primary meristem (root and shoot apices) are included in this type of meristem.
When xylem and phloem strands are present at different radii the vascular bundles are radial and 4 radial vascular bundles (tetrach condition) are present in dicot root.
This is called tetrach conditions.
Inulin is a water soluble fructosan.
It is a common reserve food in members of family compositae.
Pectin is a mucopolysaccharides and occur in plant cell walls.
At the time of fruit ripening wall of pectins hydrolyse to give constituent sugars.
In plants during vascularisation, differentiation of procambium occurs followed by the formation of primary phloem and xylem simultaneously.
Bulliform cells are large empty colourless cells that lose water and become flaccid in water scarce condition.
Hence they curl the leaf inwards to minimise water loss by reducing the exposed surface area.
The correct answer is Option B: Aleurone layer.
• The aleurone layer is a protein-rich tissue that surrounds the starchy endosperm in cereal seeds.
• It lies just beneath the seed coat and separates the endosperm from the embryo.
• In contrast: – Integuments are the tissues surrounding the ovule. – Coleoptile is the sheath covering the emerging shoot. – Coleorhiza is the sheath covering the emerging root.
The statement that is NOT correct for a typical monocot stem is: Option C: Hypodermis is parenchymatous.
Explanation: • In monocot stems – Vascular bundles are indeed conjoint (xylem + phloem together), closed (no cambium) and scattered throughout the ground tissue. – Phloem parenchyma is absent. – The hypodermis, however, is usually sclerenchymatous (providing mechanical support), not parenchymatous.
The correct answer is Option A: Sclereids .
Here's why: Sclereids are a type of sclerenchyma tissue, characterized by their thick, lignified cell walls.
These rigid cells provide structural support and protection.
They are commonly found in the hard, protective layers of nuts and the gritty texture of pear pulp.
Let's break down why the other options are incorrect : Fibres are another type of sclerenchyma tissue, but they are long and slender, providing tensile strength.
While they are present in some plant structures, they are not the primary component of nut shells or pear pulp.
Parenchyma cells are thin-walled and loosely packed, making them suitable for storage and photosynthesis.
They are found throughout plants but don't provide the same level of rigidity as sclereids.
Collenchyma cells have thickened cell walls at the corners, offering flexibility and support to young, growing tissues.
They are not typically found in mature fruit structures.
In summary, the presence of sclereids with their thick, lignified walls explains the hardness of nut shells and the gritty texture of pear pulp.
