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T.S. of dicot stem is given below, certain parts have been marked by alphabets (A I). Choose the option which shows their correct labelling.
A Epidermis, B Epidermal hair, C Parenchyma, D Starch sheath, E Hypodermis (collenchyma), F Vascular bundle, G Bundle cap, H Medulla or pith, I Medullary rays
A Epidermal hair, B Epidermis, C Hypodermis (collenchyma), D Parenchyma, E Endoderm is (Starch Sheath), F Pericycle, G Vascular bundle, H Medullary rays, I Medulla or pith
A Epidermal hair, B Epidermis, C Hypodermis (collenchyma), D Starch sheath, E Parenchyma, F Vascular bundle, G Bundle cap, H Medulla or pith, I Medullary rays
A Epidermal hair, B Epidermis, C Parenchyma, D Hypodermis (collenchyma), E Starch sheath, F Vascular bundle, G Bundle cap, H Medulla or pith, I Medullary rays
Correct Answer :
B. A Epidermal hair, B Epidermis, C Hypodermis (collenchyma), D Parenchyma, E Endoderm is (Starch Sheath), F Pericycle, G Vascular bundle, H Medullary rays, I Medulla or pith
In the given figure of dicot stem, the parts marked as A, B,C, D, E, F, G, H and I are respectively epidermal hair, epidermis, hypodermis, parenchyma, endodermis, pericycle, vascular bundle, medullary rays and medulla or pith. Dicot stems with primary growth have pith in the centre, with vascular bundles forming a distinct ring visible when the stem is viewed in cross section. The outside of the stem is covered with an epidermis, which is covered by a waterproof cuticle. The epidermis also may contain stomata for gas exchange and multicellular stem hairs called trichomes. A cortex consisting of hypodermis (collenchyma cells) and endodermis (starch containing cells) is present above the pericycle and vascular bundles. Inner to endodermis is present a few layers of heterogenous pericycle. Vascular bundles are conjoint, collateral and open. Medullary rays are present in between vascular bundles. Cambium helps in secondary growth.