Plant tissues and anatomy of root, stem, leaf
- Find the statement that is NOT correct with regard to the structure of monocot stem. Answer: 1. Hypodermis is parenchymatous. Key idea: In a monocot stem the hypodermis is sclerenchymatous, not parenchymatous. The other state... 1
- Bulliform cells are responsible for Answer: 2. Inward curling of leaves in monocots. Key idea: bulliform cells are large colourless cells on the upper epidermis of grass leaves... 1
- In the given figure, which component has thin outer walls and highly thickened inner walls? Answer: 2. C Key idea: in dicot guard cells the wall facing the stomatal pore (inner wall) is thick and the outer wall is thin. In the figur... 1
- Given below are two statements:Statement I : Parenchyma is living but collenchyma is dead tissue.Statement II : Gymnosperms lack xylem vessels but presence of xylem vessels is the characteristic of angiosperms.In the light of the above statements, ch… Answer: 1. Statement I is false but Statement II is true Key idea: check each statement against tissue properties. Statement I: Parenchyma i... 1
- Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :Assertion A : Late wood has fewer xylary elements with narrow vessels.Reason R : Cambium is less active in winters.In the light of the above statem… Answer: 2. Both A and R are true and R is the correct explanation of A. Key idea: In winter the cambium is less active and forms fewer xylar... 1
- Given below are two statements :Statement I : Endarch and exarch are the terms often used for describing the position of secondary xylem in the plant body.Statement II : Exarch condition is the most common feature of the root system.In the light of t… Answer: 1. Statement I is incorrect but Statement II is true. Key idea: Endarch and exarch describe the position of primary xylem. Statement... 1
- Identify the correct statements :A. Lenticels are the lens-shaped openings permitting the exchange of gases.B. Bark formed early in the season is called hard bark.C. Bark is a technical term that refers to all tissues exterior to vascular cambium.D.… Answer: 3. A and D only Key idea: Check each statement. A is true: lenticels allow gas exchange. B is false: bark formed early in the season... 1
- The anatomy of springwood shows some peculiar features. Identify the correct set of statements about springwood.(a) It is also called as the earlywood(b) In spring season cambium produces xylem elements with narrow vessels(c) It is lighter in colour(… Answer: 3. (a), (c), (d) and (e) Only (a) Springwood is also called earlywood: true. (b) It has wide vessels, not narrow: false. (c) It is l... 1
- "Girdling Experiment" was performed by Plant Physiologists to identify the plant tissue through which : Answer: 3. food is transported In the girdling experiment, a ring of bark (with phloem) is removed from a stem. Food accumulates above the r... 1
- In old trees the greater part of seco[...] dark brown and resistant to insect attack due [...](a) secretion of secondary metabolites and their deposition in the lumen of vessels.(b) deposition of organic compounds like tannins and resins in the centr… Answer: 2. (a) and (b) Only Heartwood is dark brown and resistant to insects and microbes because of chemical deposits in the central, old x... 1
- Which of the following is not observed during apoplastic pathway ? Answer: 4. The movement is aided by cytoplasmic streaming In the apoplastic pathway water moves only through cell walls and intercellular sp... 1
- Read the following statements about the vascular bundles :(a) In roots, xylem and phloem in a vascular bundle are arranged in an alternate manner along the different radii.(b) Conjoint closed vascular bundles do not possess cambium(c) In open vascula… Answer: 3. (b), (c), (d) and (e) Only Check each statement against NCERT; the key says statement (a) does not hold, so the answer is (b), (c... 1
- Select the correct pair. Answer: 3. Cells of medullary rays that form part of cambial ring - Interfascicular cambium Check each pair. Large colourless empty cells in... 1
- Match List - I with List - II.List - I | List - II(a) Lenticels | (i) Phellogen(b) Cork cambium | (ii) Suberin deposition(c) Secondary cortex | (iii) Exchange of gases(d) Cork | (iv) PhellodermChoose the correct answer from the options given below. Answer: 2. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii) Match the structures with their roles: Lenticels allow exchange of gases: (a)-(iii). Cork... 1
- Match List - I with List - II.List - I | List - II(a) Cells with active cell division capacity | (i) Vascular tissues(b) Tissue having all cells similar in structure and function | (ii) Meristematic tissue(c) Tissue having different types of cells |… Answer: 1. (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii) Match by definition: Actively dividing cells: meristematic tissue, (a)-(ii). All cells ali... 1
- Identify the incorrect statement. Answer: 3. Sapwood is the innermost secondary xylem and is lighter in colour. Key idea: Heartwood is the innermost secondary xylem and is da... 1
- The transverse section of a plant shows following anatomical features :(a) Large number of scattered vascular bundles surrounded by bundle sheath.(b) Large conspicuous parenchymatous ground tissue.(c) Vascular bundles conjoint and closed.(d) Phloem p… Answer: 1. Monocotyledonous stem Key idea: Scattered, conjoint, closed vascular bundles with bundle sheaths and no phloem parenchyma indicat... 1
- Phloem in gymnosperms lacks : Answer: 4. Both sieve tubes and companion cells Key idea: Gymnosperm phloem has sieve cells and albuminous cells. Sieve tubes and companion... 1
- Xylem translocates : Answer: 4. Water, mineral salts, some organic nitrogen and hormones Xylem sap carries mostly water and minerals, but also some organic nitro... 1
- Which of the statements given below is not true about formation of Annual Rings in trees ? Answer: 4. Annual rings are not prominent in trees of temperate region. Key idea: Annual rings are clearest where seasons differ sharply, so... 1
- Grass leaves curl inwards during very dry weather. Select the most appropriate reason from the following : Answer: 2. Flaccidity of bulliform cells Grass leaves have large thin-walled bulliform (motor) cells in the upper epidermis. In dry weather... 1
- Stomata in grass leaf are Answer: 1. Dumb-bell shaped Grass (monocot) leaves have dumb-bell shaped guard cells. Kidney-shaped guard cells are in dicots. Rectangular a... 1
- Plants having little or no secondary growth are Answer: 1. Grasses Secondary growth depends on a vascular cambium, which is weak or absent in monocots. Grasses are monocots with closed vas... 1
- Casparian strips occur in Answer: 4. Endodermis Casparian strips are waterproof bands of suberin on the radial and tangential walls of endodermal cells. They force wa... 1