Palisade parenchyma is absent in leaves of:
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Solution
Palisade parenchyma is absent in leaves of Sorghum. It is a leaf tissue composed of columnar cells containing numerous chloroplasts in which the long axis of each cell is perpendicular to the leaf surface. The palisade parenchyma is usually directly beneath the epidermis of the upper surface of the leaf. The cells of the palisade parenchyma are cylindrical. Neighbouring cells look like the stakes of a palisade. Cells of the palisade parenchyma contain three to five times as many chloroplasts as those of the spongy parenchyma. The chloroplasts stay usually near the cell’s wall, since this adjustment guarantees optimal use of light.
When we peel the skin of a potato tuber, we remove
The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is:
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Solution
The annular and spirally thickened conducting elements generally develop in the protoxylem when the root or stem is maturing
Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by
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Solution
Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by position of protoxylem. In dicot root the protoxylem is located near the periphery of the vascular cylinder while in dicotstem the protoxylem is located near the centre of vascular bundle i.e. the xylem is endarch
Which one of the following is resistant to enzyme action?
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Solution
Pollen exine is resistant to enzyme action. The hard outer layer called the exine is made up of sporopollenin which is one of the most resistant organic material known. It can with stand high temperatures and strong acids and alkali.No enzymes that degrades sporopollenin is so far known.
Vascular tissues in flowering plants develop from:
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Solution
Vascular tissues in flowering plants develop from plerome. Plerome is a central core of primary meristem which gives rise to all cells of the stele from the pericycle inward.
Identify the tissue system from among the following
Passage cells are thin walled cells found in
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Solution
The innermost layer of the cortex is called endodermis.It comprises a single layer of barrel shaped cells without any inter cellular spaces. In roots thick walled endodermal cells are interrupted by thin walled passage cells or transfusion tissue
For a critical study of secondary growth in plants. Which one of the following pairs is suitable?
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Solution
Teak and pine is most suitable for the study of critical secondary growth because in secondary growth,secondary tissues are formed from lateral meristem which is well developed in these two cases and secondary growth occurs in gymnosperms and dicots.
A common structural feature of vessel elements and sieve tube elements are
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Solution
In plant conducting tissue xylem has an important integral cell as xylem vessel which is without nucleus. The phloem on other hand has a row of sieve tubes which are also without nucleus at maturity.