51 Questions with Answers and Explanations on “Plant Anatomy” for Botany Students.
1. Tunica corpus theory is connected with
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(a) root apex
(b) root cap
(c) shoot apex
(d) secondary growth.
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Answer and Explanation:
1. (c): Tunica corpus theory is connected with shoot apex. The concept was proposed by Schmidt, 1924. He differentiated two zones in the shoot apex, an outer tunica and inner corpus. The tunica shows only anticlinal divisions and thus it is responsible for surface growth. Corpus is the inner mass of cells and it divides both anticlinally as well as periclinally.
2. Which meristem helps in increasing girth?
(a) lateral meristem
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(b) intercalary meristem
(c) primary meristem
(d) apical meristem.
Answer and Explanation:
2. (a): The meristem that helps in increasing girth is lateral meristem. The lateral meristem is responsible for lateral growth of the plant i.e., growth in thickness e.g., cambium and cork cambium. It divides only periclinally or radially and is responsible for increase in girth or diameter.
3. Cork is formed from
(a) cork cambium (phellogen)
(b) vascular cambium
(c) phloem
(d) xylem.
Answer and Explanation:
3. (a): In hypodermis or outer cortical cells, a layer becomes meristematic which is known as cork cambium or phellogen. This phellogen also cuts off cells both on its outer side and inner side. The cells cut off on outer side are phellem or cork cells and cells cut off on inner side are phelloderm or secondary cortex.
The phellem or cork cells are dead and have deposition of a fatty substance called suberin (i.e., cork cells are suberized). Suberin is impervious to water and thus cork cells are buoyant (i.e., float on water). Phellem, phellogen and phelloderm collectively constitute periderm.
4. Pith and cortex do not differentiate in
(a) monocot stem
(b) dicot stem
(c) monocot root
(d) dicot root.
Answer and Explanation:
4. (a): Pith and cortex do not differentiate in monocot stem. Since numerous vascular bundles lie scattered, the ground tissue system in a monocot stem is distinguishable into hypodermis and ground parenchyma.
5. Organisation of stem apex into corpus and tunica is determined mainly by
(a) planes of cell division
(b) regions of meristematic activity
(c) rate of cell growth
(d) rate of shoot tip growth.
Answer and Explanation:
5. (a): The tunica corpus concept was given by Schmidt (1924) which was based on plane of divisions of cells. According to this concept there are two portions in shoot apex tunica and corpus. The tunica shows only anticlinical divisions and thus it is responsible for surface growth. The corpus shows divisions in all plane and thus responsible for volume growth.
6. Death of protoplasm is a pre-requisite for a vital function like.
(a) transport of sap
(b) transport of food
(c) absorption of water
(d) gaseous exchange.
Answer and Explanation:
6. (a): Death of protoplasm is a pre-requisite for a vital functions like transport of sap. Xylem is a dead tissue and do not have protoplasm, xylem performs the function of transport of water or sap inside the plant from roots.
7. Sieve tubes are suited for translocation of food because they possess
(a) bordered pits
(b) no ends walls
(c) broader lumen and perforated cross walls
(d) no protoplasm.
Answer and Explanation:
7. (c): Sieve tubes are suited for translocation of food because they possess broader lumen and perforated cross walls. Sieve tubes are elongated tubular conducting channels of phloem. The end wall possesses many small pores and have thin cellulosic wall.
8. Out of diffuse porous and ring porous woods, which is correct
(a) ring porous wood, carries more water for short period
(b) diffuse porous wood carries more water
(c) ring porous wood carries more water when need is higher
(d) diffuse porous wood is less specialised but conducts water rapidly throughout. (1989)
Answer and Explanation:
8. (c): Ring porous wood carries more water when need is higher. Ring porous wood provides better translocation when requirement of plant is more. Hence, it is very advanced than diffuse porous wood.
9. Cork cambium and vascular cambium are
(a) parts of secondary xylem and phloem
(b) parts of pericycle
(c) lateral meristem
(d) apical meristem.
Answer and Explanation:
9. (c): Cork cambium and vascular cambium are lateral meristems. Both are responsible for the secondary growth of stem. It also increases the girth of stem.
10. Monocot leaves possess
(a) intercalary meristem
(b) lateral meristem
(c) apical meristem
(d) mass meristem.
Answer and Explanation:
10. (a): Monocot leaves possess intercalary meristem. Intercalary meristem are responsible for localised growth. Perhaps they have been separated or detached from the mother meristem e.g., meristem present at the base of leaves in many monocots, in the internode of grasses, at the top of peduncles of Plantago and Taraxacum etc.
11. Collenchyma occurs in the stem and petioles of
(a) xerophytes
(b) monocots
(c) dicot herbs
(d) hydrophytes.
Answer and Explanation:
11. (c): Collenchyma occurs in the stem and petioles of dicot herbs. Due to deposition of pectin, it has high water retaining capacity. Since pectin appears at the angles, it becomes a spongy tissues. The collenchyma is a mechanical tissue which gives tensile strength to the plant.
12. Collenchyma occurs is
(a) herbaceous climbers
(b) woody climbers
(c) climbing stems
(d) water plants.
Answer and Explanation:
12. (c): Collenchyma occurs in climbing stems. Collenchyma occurs in the stem and petioles of dicot herbs. Due to deposition of pectin, it has high water retaining capacity. Since pectin appears at the angles, it becomes a spongy tissues. The collenchyma is a mechanical tissue which gives tensile strength to the plant.
13. Pericycle of roots produces
(a) mechanical support
(b) lateral roots
(c) vascular bundles
(d) adventitious buds.
Answer and Explanation:
13. (b): Pericycle of root produces lateral roots. Endodermis is followed by pericycle. Usually it is a continuous layer but in some monocots it is interrupted by xylem and phloem. It is the seat of origin of lateral roots and cork cambium. The root branches are, therefore described as endogenous in origin.
14. For union between stock and scion in grafting which one is the first to occur
(a) formation of callus
(b) production of plasmodesmata
(c) differentiation of new vascular tissues
(d) regeneration of cortex and epidermis.
Answer and Explanation:
14. (a): Grafting is a techinque in which cambium bearing shoot (scion = graft) of one plant is joined to cambium bearing stump (root system = stock) of a related plant through different unions like tongue grafting, wedge grafting etc. In grafting union between stock and scion produces undifferentiated mass of cells called callus. Therefore, for union between stock and scion in grafting, first to occur is the formation of callus. Callus is more or less corky secondary tissue developed lay woody plants over a wound. It is derived from cambium.
15. What is true about a monocot leaf
(a) reticulate venation
(b) absence of bulliform cells from epidermis
(c) mesophyll not differentiated into palisade and spongy tissues
(d) well differentiated mesophyll.
Answer and Explanation:
15. (c): In monocot leaf, mesophyll cells are not differentiated into palisade and spongy tissues. But there is well differentiate mesophyll cells in dicot stem. Also in the upper epidermis, there are some large cells found in groups which are called bulliform cells. The venation pattern in monocot is parallel.
16. Vascular cambium produces
(a) primary xylem and primary phloem
(b) secondary xylem and secondary phloem
(c) primary xylem and secondary phloem
(d) secondary dylem and primary phloem.
Answer and Explanation:
16. (b): Vascular cambium produces secondary xylem and secondary phloem. It is developing from the procambium which is an embryonic tissue, hence it is primary in origin. It is secondary in function for it forms the secondary tissues like secondary xylem, secondary phloem and secondary medullary rays. The cambium is a radially one cell thick zone of meristematic cells.
17. Where do the casparian bands occur
(a) epidermis
(b) endodermis
(c) pericycle
(d) phloem.
Answer and Explanation:
17. (b): The innermost layer of soft cortex is called as endodermis. This uniseriate layer is characterised by the presence of casparian strips. This thickenings was first observed by Caspary, 1865 and hence the name.
18. Angular collenchyma occurs in
(a) Cucurbita
(b) Helianthus
(c) Althaea
(d) Salvia.
Answer and Explanation:
18. (a): Angular collenchyma occurs in, Cucurbita. It has thickening at the angles and there are no intercellular spaces. It is generally found in leaf petioles.
19. An organised and differentiated cellular structure having cytoplasm but no nucleus is
(a) vessels
(b) xylem parenchyma
(c) sieve tubes
(d) tracheids.
Answer and Explanation:
19. (c): An organised and differentiated cellular structure ‘ having cytoplasm but no nucleus are sieve tubes. The sieve tubes are living cells. Their walls are thicker than surrounding parenchyma cells. Sometimes they have a special, shinning nacreous thickening. Cytoplasm occurs in the form of thin lining enclosing a big central vacuole.
20. Which is correct about transport of conduction of substances?
(a) organic food moves up through phloem
(b) organic food moves up through xylem
(c) inorganic food moves upwardly and downwardly through xylem
(d) organic food moves upwardly and downwardly through phloem.
Answer and Explanation:
20. (d): Phloem is the food conducting tissue of plants. The sieve tubes are food conducting elements of the plants. It is proposed that food is translocated by mass flow or by streaming currents of protoplasm.
21. A bicollateral vascular bundle is characterised by
(a) phloem being sandwitched between xylem
(b) transverse splitting of vascular bundle
(c) longitudinal splitting of vascular bundle
(d) xylem being sandwitched between phloem.
Answer and Explanation:
21. (d): A bicollateral vascular bundles is characterised by xylem being sandwiched between phloem. Here there are two cambuim rings e.g., Cucurbita.
22. Bordered pits are found in
(a) sieve cells
(b) vessel wall
(c) companion cells
(d) sieve tube wall.
Answer and Explanation:
22. (b): Bordered pits are found in vessel wall. In bordered pits, the thickening materia over arches the pit cavity in such a way that a pit chamber ope; is to the interior by a pit aperture.
23. Abnormal/anomalous secondary growth occurs in
(a) Dracaena
(b) ginger
(c) wheat
(d) sunflower.
Answer and Explanation:
23. (a): Monocot trees such as palms grow in thickness by primary thickening meristem situated at the base of the leaf. Plants like Dracaena show secondary growth by a special cambium. It develops in the form of strips just outside the vascular region. These cambial strips produce secondary vascular bundles which is amphivasal in Dracaena.
24. Which exposed wood will decay faster?
(a) sapwood
(b) softwood
(c) wood with lot of fibres
(d) heartwood.
Answer and Explanation:
24. (a): Sap wood will decay faster. Sap wood is less durable because it is susceptible to attack by pathogen and insects.
25. A narrow layer of thin walled cells found between phloem/bark and wood of a dicot is
(a) cork cambium
(b) vascular cambium
(c) endodermis
(d) pericycle.
Answer and Explanation:
25. (b): A narrow layer of thin walled cells found between phloem/bark and wood of dicot is vascular cambium. Vascular cambium present inside a vascular bundle is called as intrafascicular cambium or fascicular cambium. The vascular cambium is a meristematic tissue.
26. Periderm is produced by
(a) vascular cambium
(b) fascicular cambium
(c) phellogen
(d) intrafascicular cambium.
Answer and Explanation:
26. (c): Periderm is produced by phellogen. The phellogen forms phellem on the outer face and phelloderm on the inner. The three layers i.e., phellem, phellogen and phelloderm jointly constitute the periderm.
27. Which of the following plant cells will show totipotency
(a) sieve tubes
(b) xylem vessels
(c) meristem
(d) cork cells.
Answer and Explanation:
27. (c): Meristems shows the totipotency because xylem vessels and cork cells are dead while sieve tube cells do not possess nuclei.
28. As a tree grows older, which of the following increases more rapidly in thickness?
(a) heart wood
(b) sap wood
(c) phloem
(d) cortex.
Answer and Explanation:
28. (a): Heartwood or duramen is the dark coloured wood near the centre of the axis formed after many years of secondary growth of stem. A small outer region, however, remains light coloured. It is known as sap wood or alburnum. The heartwood is formed due to changes in the elements of the secondary xylem.
As secondary growth precedes most of the older elements of secondary xylem lose water and become filled with organic compounds such as oils, gums, resins, tannins, and aromatic and colouring materials. The wood becomes dark coloured due to accumulating of these substances and is also termed as duramen.
The sap wood is the light coloured region of the secondary xylem. Cells of this region are functionally active. The elements of the secondary xylem added by cambial activity are those of sap wood. But gradually most of these elements get transformed into heart wood. Thus the amount of heart wood increases as the tree grows older. The amount of sap wood, however, remains almost constant.
29. Casparian strip occurs in a
(a) endodermis
(b) exodermis
(c) pericycle
(d) epidermis.
Answer and Explanation:
29. (a): Endodermis is single layered structure which separates cortex from stele. The cells of endodermis are barrel-shaped without intercellular spaces, living and containing starch. The radial and tangential walls of endodermal cells possess thickenings of lignin, suberin and cutin in the form of strips or bands, which are known as casparian bands or casparian strips.
30. Which of the following is not true about ‘sclereids’?
(a) these are groups of living cells
(b) these are found in nut shells, guava pulp, pear
(c) these are also called stone cells
(d) these are form of sclerenchyma with fibres.
Answer and Explanation:
30. (a): Sclereids are a type of sclerenchyma cells. They are short or irregular, their walls are very thick, irergular and the lumen is very narrow. These are dead cells and
do not perform any metabolic functions. They show different types of lignin depositions and also have pits. They are present in hard parts like endocarp of coconut, hard seed coats fruit pulps. They are also called stone cells and are different types as brachysclereids, osteoclereids, macrosclereids, asterosclercids and fileform cells.
31. At maturity, which of the following is non- nucleated?
(a) palisade cell
(b) cortical cell
(c) sieve cell
(d) companion cell.
Answer and Explanation:
31. (c): In pteridophytes and gymnosperms, sieve tubes are not arranged in linear rows and hence called sieve cells. Sieve tube elements are the conducting element of phloem. These are arranged end to end in linear rows with septa (sieve plate) between two sieve tube elements. In the sieve plate, there are present sieve pores. Sieve tube elements are living and have thin cellulosic walls in young cells but they become thick walled and are without nuclei at maturity.
32. The periderm includes
(a) secondary phloem
(b) cork
(c) cambium
(d) all of these.
Answer and Explanation:
33. (c): Extra stelar secondary growth means growth in the cortical region, external to slele. For extrastelar secondary growth the cork cambium or phellogen develops in the region outside the vascular tissue. This gives rise to cork or phellem and secondary cortex or phelloderm. All the three layers (i.e, cork, cork cambium and secondary cortex) together constitute periderm. Fascicular and inter fascicular cambuim occurs in the stelar regions.
33. Which of the following meristems is responsible for extrastelar secondary growth in dictyledonous stem?
(a) interfascicular cambium
(b) intercalary meristem
(c) phellogen
(d) intrafascicular cambium.
Answer:
(c) phellogen
34. Casparian strips are found in
(a) epidermis
(b) hypodermis
(c) periderm
(d) endodermis.
Answer and Explanation:
34. (d): Refer answer 29.
35. What happens in plants during vascularisation?
(a) differentiation of procambium, formation of primary phloem followed by formation of primary xylem
(b) differentiation of procambium followed by the formation of primary phloem and xylem simultaneously
(c) formation of procambium, primary phloem and xylem simultaneously
(d) differentiation of procambium followed by the formation of secondary xylem. (2000)
Answer and Explanation:
35. (b): In plants during vascularisation, differentiation of procambium occurs followed by the formation of primary phloem and xylem simultaneously.
36. in plants inulin and pectin are
(a) reserved material
(b) wastes
(c) excretory material
(d) insect attracting material.
Answer and Explanation:
36. (a): Inulin is a water soluble fructosan. It is a common reserve food in members of family compositae. Pectin in a mucopolysaccharides and occur in plant cell walls. At the time of fruit ripening wall pectins hydrolyse to give constituent sugars.
37. Vessels are found in
(a) all angiosperms and some gymnosperm
(b) most of angiosperms and few gymnosperms
(c) all angiosperms, all gymnosperms and some pteridophyta
(d) all pteridophyta.
Answer and Explanation:
37. (b): Vessels are long tubelike structures ideally suited for the conduction of water and solutes. These are made up of a row of cylindrical cells arranged in longitudinal series. The partition walls of these cells are perforated and as such the entire structure becomes tubelike.
The region of the wall where perforations occur is known as perforation plate. Vessels are found in the wood of almost all the angiosperms except certain primitive members of the order ranales (vesseless dicots), e.g., Trochodendron, Tetracentron, Drimys, Pseudowintera, etc.
Vessels also occur in some pteridophytes, such as Selaginella and in the members of order Gnetales of gymnosperms (e.g., Genetum, Ephedra and Welwitschia).
38. Four radial vascular bundle are found in
(a) dicot root
(b) monocot root
(c) dicot stem
(d) monocot stem.
Answer and Explanation:
38. (a): The vascular tissue of the root is characterised by radial arrangement of vascular bundles i.e., xylem and phloem occur in separate patches on alternate radii. The numbers of xylem and phloem groups vary from two to six. But tetrarch condition (four vascular bundles) is more common. Monocot root generally has more than six vascular bundles (polyarch). Vascular bundles in dicot stems are conjoint, collateral or bicollateral, endarch and open. They are arranged in a ring.
In monocot stems the vascular bundles are conjoint, collateral, endarch and closed. They are scattered in the ground tissue.
39. Axillary bud and terminal bud derived from the activity of
(a) lateral meristem
(b) intercalary meristem
(c) apical meristem
(d) parenchyma.
Answer and Explanation:
39. (c): 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 sh'”>t apices) are included in this type of meristem.
40. Which of the following statement is true:
(a) vessels are multicellular with wide lumen
(b) tracheids are multicellular with narrow lumen
(c) vessels are unicellular with narrow lumen
(d) tracheids are unicellular with wide lumen.
Answer and Explanation:
40. (d): Xylem is the principal water conducting tissue of the plant. It consists of four types of cells-tracheids, vessels, xylem Fibres and xylem parenchyma. The tracheids and vessels together are known as tracheary elements.
Tracheids are characteristic of all vascular plant. Tracheids originate from single cells. These are single elongated cells with tapering ends. The end walls are without perforations. Their length varies from 1 to 3 mm. Tracheids are devoid of protoplast, hence dead; fairly large cavity of these cells is without any contents. The wall of tracheids is moderately thick and usually Iignified.
41. The cells of the quiescent centre are characterised by
(a) having dense cytoplasm and prominent nuclei
(b) having light cytoplasm and small nuclei
(c) dividing regularly to add tothe corpus
(d) dividing regularly to add to tunica (2003)
Answer and Explanation:
41. (b): In the apices of some roots, (e.g., Zea mays, maize), there is a central region of cells which normally does not divide. This central inactive region was called quiescent centre by F.A.L. Clowes (1959, 1961). The cells of this region have lesser amounts of RNA and DNA’ so they have small nuclei.
These cells also have a lower rate of protein synthesis. Mitochondria and endoplasmic reticulum are less developed. The cells of the quiescent centre are usually inactive. However, if already existing meristematic cells are injured or become inactive due to any other reason, the cells of quiescent centre become active.
42. Diffuse porous woods are characteristic of plants growing in
(a) alpine region
(b) cold winter regions
(c) temperature climate
(d) tropics
Answer and Explanation:
42. (d): In most of the gymnosperms, like conifers and cycads, vessels are absent and the wood is made entirely of tracheids. Such wood is known as nonporous.
In angiosperms, on the other hand, the wood consists of both tracheids and vessels. The wide vessels appear as pores between otherwise small sized tracheary elements. Such a wood is known as porous. In porous wood, if vessels have essentially equal diameters and are uniformly distributed throughout the ring, the wood is known as diffuse porous. It is characteristic of plants grocourg in tropics.
43. Chlorenchyma is known to develop in the
(a) cytoplasm of Chlorella
(b) mycelium of a green mould such as Aspergillus
(c) spore capsule of a moss
(d) pollen tube of Pinus
Answer and Explanation:
43. (c): Chlorenchyma or assimilatory parenchyma are parenchymatous cells that possess abundant chioroplasts in them. They are capable of photosynthesis. A spore capsule of moss can perform photosynthesis because of the presence of chlorenchyma cells in them.
44. The aleurone layer in maize grain is specially rich in
(a) proteins
(b) starch
(c) lipids
(d) auxins
Answer and Explanation:
44. (a): In monocotyledons the seeds are generally endospermous. The internal structure of grain can be studied in a longitudinal section. It shows two distinct regions upper large region, the endosperm and lower smaller region, the embryo. The endosperm is surrounded by a special one cell thick layer, called aleurone layer. It is filled with aleurone grains which are proteinaceous in nature. Other components of this layer are phytin, carbohydrates and small amounts of phospholipids are also present.
45. In which one of the following is nitrogen not a constituent?
(a) idioblast
(b) bacteriochlorophyll
(c) invertase
(d) pepsin
Answer and Explanation:
45. (a): The major storage component of Avocado fruit is oil. It is stored in specialized mesocarp cells called idioblast.
46. The apical meristem of the root is present
(a) only in radicals
(b) only in tap roots
(c) only in adventitious roots
(d) in all the roots
Answer and Explanation:
46. (d): Parts of typical root : root cap, meristematic growing region, zone of elongation, root hair zone, zone of meriste-matic cells.
Apical meristem is terminal in position and responsible for terminal growth of the plant. Apical meristem is present at all root tips and shoot tips.
The zones, successively from the apex to the base are-
1. Root cap zone: The apex of each root is covered by a cushion of thin walled cells known as root cap.
2. Region of cell division: It lies just behind the root cap. It is the main growing region of the root where active cell divisions take place.
3. Region of elongation: The region of elongation is responsible for growth in length of the root.
4. Region of maturation: Epidermal cells of this region give out small, thin, cylindrical unicellular outgrowths, known as root hairs. These are the main absorbing organs of the root.
47. In a longitudinal section of a root, starting from the tip upward, the four zones occur in the following order:
(a) root cap, cell division, cell enlargement, cell maturation
(b) root cap, cell division, cell maturation, cell enlargement
(c) cell division, cell enlargement, cell maturation, root cap
(d) cell division, cell maturation, cell enlargement, root cap.
Answer:
(a) root cap, cell division, cell enlargement, cell maturation
48. In a woody dicotyledonous tree, which of the following parts will mainly consist of primary tissues?
(a) all parts
(b) stem and root
(c) flowers, fruits and leaves
(d) shoot tips and root tips.
Answer and Explanation:
48. (c): The tissues which develop from apical meristem and procambium are known as primary tissues and these constitute the primary structures of the plant body. The development of the primary tissues causes the stem to grow in length and to some extent in thickness. Stem and root in dicotyledons show secondary growth as they have development of secondary vascular tissues (i.e., secondary xylem and secondary phloem) in them. Flowers, fruits and leaves are primary tissues.
49. A common structural feature of vessel elements and sieve tube elements is
(a) enucleate condition
(b) thick secondary walls
(c) pores on lateral walls
(d) presence of P-protein
Answer and Explanation:
49. (a): Xylem is the principal water conducting tissue of the plant. It consists of four types of cells-tracheids, vessels, xylem fibres and xylem parenchyma.
Xylem vessels are hollow, elongated cells with open ends and pitted walls. Cells walls are Iignified. At maturity nucleus is absent in vessels.
The constituent cells of the phloem are sieve elements (sieve cells, sieve tubes), companion cells, phloem fibres and phloem parenchyma cells.
Sieve tube members are long, slender, tube-like cells joined end to end, to form long tubular channels – the sieve tubes. Sieve tube members possess specialized sieve areas on the end walls called sieve plate. Young sieve tube members have abundant cytoplasm but there is no nucleus. The nucleus disintegrates during their development.
50. For a critical study of secondary growth in plants, which one of the following pairs is suitable?
(a) teak and pine
(b) deodar and fern
(c) wheat and maiden hair fern
(d) sugarcane and sunflower.
Answer and Explanation:
50. (a): Secondary growth is observed in dicots and gymnosperm. It is not observed in pteridophytes and rarely observed in monocots. Secondary growth results in increase in girth or diameter of the stem by formation of secondary tissue by the activity of lateral meristem. So for study of secondary growth, teak (angiosperm) and pine (gymnosperm) are best suited.
51. Passage cells are thin – walled cells found in
(a) phloem elements that serve as entry points for substance for transport to other plant parts
(b) testa of seeds to enable emergence of growing embryonic axis during seed germination
(c) central region of style through which the pollen tube grows towards the ovary
(d) endodermis of roots facilitating rapid transport of water from cortex to pericycle.
Answer and Explanation:
51. (d): Endodermis is a single layered structure which separates cortex from stele. There are both thick walled and thin walled cells in the endodermis. The thin walled cells are known as passage cells or transfusion cells which are opposite the protoxylem groups. These cells help in rapid transport of water from cortex to pericycle.