In the exponential growth equation W1 = W0ert, consider the following statements:
(i) W1 represents the final size (weight, height, number), and W0 represents initial size. (ii) r represents the relative growth rate and is a measure of the ability to produce new plant material. (iii) r is also referred to as the efficiency index of the plant. (iv) Final size W1 is completely independent of initial size W0.
Statements (i), (ii), and (iii) are correct because in W1 = W0ert, r is the relative growth rate and efficiency index. Statement (iv) is incorrect because final size W1 directly depends on initial size W0.
Question 12 of 100
📘 CLASS XI
Compare absolute and relative growth rates based on leaf growth parameters:
(i) Measurement and comparison of total growth per unit time is called absolute growth rate. (ii) Growth of a system per unit time expressed on a common basis (per unit initial parameter) is relative growth rate. (iii) Two leaves of different initial sizes showing equal absolute increase in area have identical relative growth rates. (iv) A smaller leaf showing the same absolute area increase as a larger leaf exhibits a higher relative growth rate.
Statements (i), (ii), and (iv) are correct because relative growth rate calculates increase relative to initial parameter, so smaller initial size gives higher relative growth rate for equal absolute growth. Statement (iii) is incorrect because equal absolute growth on different initial sizes results in different relative growth rates.
Question 13 of 100
📘 CLASS XI
Which of the following environmental and internal factors are essential conditions for plant growth?
(i) Water provides turgidity for cell enlargement and medium for enzymatic activities. (ii) Oxygen helps in releasing metabolic energy essential for growth activities. (iii) Nutrients (macro and micro essential elements) act as source of energy and synthesis of protoplasm. (iv) Every plant organism lacks a specific optimum temperature range and grows equally at all temperatures.
Statements (i), (ii), and (iii) correctly describe essential roles of water, oxygen, and nutrients. Statement (iv) is incorrect because plants have an optimum temperature range, and deviations can be detrimental.
Question 14 of 100
📘 CLASS XI
Consider the structural and protoplasmic changes occurring during differentiation of tracheary elements:
(i) Cells lose their protoplasm during maturation into tracheary elements. (ii) They develop strong, elastic, lignocellulosic secondary cell walls. (iii) Lignocellulosic walls enable water transport to long distances under extreme tension. (iv) Tracheary elements retain active dividing capacity throughout the plant's life.
Statements (i), (ii), and (iii) are correct because tracheary elements lose protoplasm and gain lignocellulosic walls for water transport under tension. Statement (iv) is incorrect because differentiation involves permanent loss of division capacity in these mature elements.
Question 15 of 100
📘 CLASS XI
Examine the phenomenon of dedifferentiation in plants:
(i) Living differentiated cells that lost division capacity regain the capacity to divide under certain conditions. (ii) Formation of interfascicular cambium from fully differentiated parenchyma cells is an example of dedifferentiation. (iii) Cork cambium formation from parenchyma is a classic manifestation of dedifferentiation. (iv) Dedifferentiated cells lose their division capacity immediately without producing any new cells.
Statements (i), (ii), and (iii) correctly define dedifferentiation and cite interfascicular cambium and cork cambium as prime examples. Statement (iv) is incorrect because dedifferentiated meristems divide actively to produce cells that subsequently redifferentiate.
Question 16 of 100
📘 CLASS XI
Regarding the concept of redifferentiation in woody dicotyledonous plants, evaluate these statements:
(i) Redifferentiation is the process where cells produced by dedifferentiated meristems lose division capacity and mature. (ii) Secondary vascular tissues (secondary xylem and secondary phloem) are products of redifferentiation. (iii) Cork (phellem) and secondary cortex (phelloderm) are redifferentiated tissues derived from cork cambium. (iv) Interfascicular cambium itself is a product of redifferentiation.
Statements (i), (ii), and (iii) are correct because cells derived from interfascicular cambium and cork cambium redifferentiate into secondary tissues. Statement (iv) is incorrect because interfascicular cambium is formed by dedifferentiation.
Question 17 of 100
📘 CLASS XI
What is meant by open differentiation in higher plants?
(i) Cells or tissues arising out of the same meristem have different structures at maturity. (ii) The final structure of a cell/tissue at maturity is determined by its location within the plant body. (iii) Cells positioned away from root apical meristem differentiate as root-cap cells. (iv) Cells pushed to the periphery mature as epidermal cells.
All four statements (i, ii, iii, iv) accurately explain open differentiation and position-dependent cellular fate in plants.
Question 18 of 100
📘 CLASS XI
Analyze the phenomenon of plasticity and heterophylly in plants:
(i) Plasticity is the ability of plants to follow different pathways in response to environment or life phases to form different structures. (ii) Heterophylly in cotton, coriander, and larkspur is an example of developmental plasticity. (iii) In larkspur, leaves of juvenile plants differ in shape from those in mature plants. (iv) Difference in leaf shapes produced in air and water in buttercup represents environmental plasticity.
All four statements (i), (ii), (iii), and (iv) are correct statements detailing plasticity and heterophylly in cotton, coriander, larkspur, and buttercup.
Question 19 of 100
📘 CLASS XI
Examine the sequence of developmental processes in a plant cell:
(i) Sequence involves: Meristematic cell → Plasmatic growth → Expansion → Differentiation → Maturation → Mature cell → Senescence → Death. (ii) Development is broadly defined as the sum of growth and differentiation. (iii) Cell division is completely absent during the developmental pathway of plant tissues. (iv) Senescence precedes maturation in the sequence of plant cell development.
Statements (i) and (ii) correctly represent the developmental sequence and definition (development = growth + differentiation). Statements (iii) and (iv) are incorrect because cell division initiates development and maturation precedes senescence.
Question 20 of 100
📘 CLASS XI
Which of the following represent intrinsic and extrinsic factors controlling plant growth and development?
(i) Intracellular factors include genetic factors. (ii) Intercellular factors include plant growth regulators (PGRs). (iii) Extrinsic factors include light, temperature, water, oxygen, and nutrition. (iv) Extrinsic factors act completely independently of plant growth regulators.
Statements (i), (ii), and (iii) are correct regarding intracellular, intercellular, and extrinsic controls. Statement (iv) is incorrect because many extrinsic factors like temperature and light control growth via PGRs.
