Assertion (A): Plums, roses, and peaches have half-inferior ovaries. Reason (R): In these plants, the gynoecium is situated in the center and other parts of the flower are located on the rim of the thalamus almost at the same level.
This describes a perigynous flower, where the gynoecium is central and the other floral whorls are borne on the rim of the cup-shaped or disc-shaped thalamus at almost the same horizontal level. Consequently, the ovary is described as half-inferior, as seen in plum, rose, and peach.
Question 142 of 300
📘 CLASS XI
Statement I: In epigynous flowers, the margin of the thalamus grows upward, enclosing the ovary completely and fusing with it. Statement II: The ovary in epigynous flowers is said to be superior because other floral parts arise above it. Select the correct option:
Statement I is correct. Statement II is incorrect because in epigynous flowers, the other floral parts arise above the ovary, which makes the ovary inferior (not superior) since it is completely enclosed and situated below the attachment point of the other whorls.
Question 143 of 300
📘 CLASS XI
Assertion (A): Petals are usually brightly colored to attract insects for pollination. Reason (R): The corolla is composed of sepals, which are green and leaf-like to protect the flower in the bud stage.
The Assertion is true. The Reason is false because the corolla is composed of petals, not sepals. (The calyx is composed of sepals, which protect the flower in the bud stage).
Question 144 of 300
📘 CLASS XI
Assertion (A): In Calotropis, the aestivation of sepals/petals is described as valvate. Reason (R): The margins of individual petals in Calotropis overlap each other in a specific, clockwise direction.
The Assertion is true; Calotropis shows valvate aestivation. The Reason is false because in valvate aestivation, the sepals or petals in a whorl just touch one another at the margins without overlapping. Overlapping in one direction is twisted aestivation.
Question 145 of 300
📘 CLASS XI
Statement I: In imbricate aestivation, the margins of sepals or petals overlap one another but not in any particular direction, as in Cassia and gulmohur. Statement II: Vexillary aestivation is also known as papilionaceous aestivation and is characteristic of pea and bean flowers. Select the correct option:
Both statements are correct. Imbricate aestivation is found in Cassia and gulmohur. Vexillary (or papilionaceous) aestivation is found in pea and bean flowers.
Question 146 of 300
📘 CLASS XI
Assertion (A): Vexillary aestivation is a highly specialized zygomorphic floral trait. Reason (R): It consists of a large posterior standard, two lateral wings, and two fused or touching anterior keels, which can only be divided symmetrically in a single vertical plane.
Vexillary aestivation is characteristic of pea and bean flowers, which are zygomorphic (bilaterally symmetrical). The distinct bilateral arrangement of standard, wings, and keel means the flower has only a single plane of symmetry, making R a correct logical explanation of A.
Question 147 of 300
📘 CLASS XI
Statement I: Corolla shape in flowering plants is always constant and restricted to a tubular form. Statement II: Petals are brightly colored in all angiosperms, including wind-pollinated grass species. Select the correct option:
Both statements are incorrect. Corolla shape varies greatly and can be tubular, bell-shaped, funnel-shaped, or wheel-shaped. Petals are usually brightly colored to attract insect pollinators, but in wind-pollinated plants (like grasses), petals are highly reduced, dull, or absent.
Question 148 of 300
📘 CLASS XI
Assertion (A): In some plants, a sterile stamen is present which cannot produce functional pollen. Reason (R): A sterile stamen is biologically termed as a staminode.
Both statements are true. A sterile, non-functional stamen is indeed a staminode. While the reason defines the term, it is a statement of nomenclature and does not explain why or how a sterile stamen forms or exists, making B the correct choice.
Question 149 of 300
📘 CLASS XI
Assertion (A): In Salvia and mustard, there is a variation in the length of stamen filaments within a single flower. Reason (R): Filament length variation is an anatomical mechanism that helps optimize pollen deposition on pollinators or the stigma.
Both statements are true. There is indeed a variation in the length of filaments within a flower in Salvia and mustard. This variation is an evolutionary adaptation that influences pollination biology and pollen placement, but the statement in R describes the physiological/ecological utility of filament variation, whereas A is a descriptive anatomical fact. Thus, R does not directly serve as a causal physiological explanation of the anatomical state in A.
Question 150 of 300
📘 CLASS XI
Statement I: An apocarpous gynoecium consists of more than one carpel, and they are fused together as in mustard and tomato. Statement II: A syncarpous gynoecium consists of fused carpels, as seen in lotus and rose. Select the correct option:
Both statements are incorrect. In apocarpous gynoecium, more than one carpel is present and they are free (not fused), as in lotus and rose. In syncarpous gynoecium, the carpels are fused, as in mustard and tomato.
