Assertion (A): In cymose inflorescences, the growth of the main floral axis is limited. Reason (R): The main axis in a cymose inflorescence terminates in a flower.
In cymose inflorescences, the main axis terminates in a flower, which physically halts further apical growth, making the growth of the axis limited.
Question 132 of 300
📘 CLASS XI
Statement I: In a racemose inflorescence, the youngest flower is always found at the base of the axis. Statement II: In a cymose inflorescence, the youngest flower is always found at the base or periphery of the axis. Select the correct option:
Statement I is incorrect because in racemose inflorescences, flowers are borne in acropetal succession, meaning the oldest flower is at the base and the youngest is at the apex. Statement II is correct because in cymose inflorescences, the oldest flower is at the apex, so younger flowers are borne basipetally (closer to the base or outer margins).
Question 133 of 300
📘 CLASS XI
Assertion (A): In Alstonia, three or more leaves are attached at each stem node. Reason (R): Alstonia displays alternate phyllotaxy to prevent leaves from shading each other.
The Assertion is true because Alstonia has more than two leaves arising at a node, forming a whorled arrangement. The Reason is false because Alstonia exhibits whorled phyllotaxy, not alternate phyllotaxy.
Question 134 of 300
📘 CLASS XI
Assertion (A): Guava exhibits opposite phyllotaxy, meaning two leaves are attached at every node opposite to each other. Reason (R): Opposite phyllotaxy allows the two leaves at a node to receive equal amounts of horizontal sunlight without shading each other's lamina at that node.
Both statements are true. In opposite phyllotaxy (as in guava), a pair of leaves arise at each node and lie opposite to each other. This spatial arrangement helps leaves capture light without direct physical self-shading at that node, but the physiological utility (R) is a functional consequence, not the anatomical definition of "opposite phyllotaxy" given in (A).
Question 135 of 300
📘 CLASS XI
Statement I: In a mustard plant, leaves arise one by one at each successive node in an alternate fashion. Statement II: The sunflower plant displays whorled phyllotaxy because its flowers are clustered in a large head. Select the correct option:
Statement I is correct; mustard displays alternate phyllotaxy where a single leaf arises at each node in an alternate manner. Statement II is incorrect because sunflower displays alternate phyllotaxy, not whorled. (The large head is an inflorescence, not related to leaf phyllotaxy).
Question 136 of 300
📘 CLASS XI
Assertion (A): Mustard, datura, and chilli possess actinomorphic flowers. Reason (R): Actinomorphic flowers display radial symmetry, meaning they can be divided into two equal halves in any radial plane passing through the center.
Mustard, datura, and chilli have actinomorphic (radially symmetrical) flowers. The reason correctly defines actinomorphic symmetry: the flower can be divided into two equal radial halves in any radial plane passing through the central axis.
Question 137 of 300
📘 CLASS XI
Statement I: Zygomorphic flowers show bilateral symmetry and can be divided into two similar halves in only one particular vertical plane. Statement II: Pea, gulmohur, bean, and Cassia have actinomorphic flowers. Select the correct option:
Statement I is correct; zygomorphic flowers are bilaterally symmetrical and divisible into two similar halves only in a single particular vertical plane. Statement II is incorrect because pea, gulmohur, bean, and Cassia are classic examples of zygomorphic flowers, not actinomorphic.
Question 138 of 300
📘 CLASS XI
Assertion (A): Canna has a flower that is termed asymmetric or irregular. Reason (R): It cannot be divided into two similar halves by any vertical plane passing through the center.
Canna is classified as asymmetric because there is no vertical plane passing through its center that can divide the flower into two similar/equal halves.
Question 139 of 300
📘 CLASS XI
Statement I: Bracts are reduced leaves found at the base of the pedicel, and flowers with them are called bracteate. Statement II: Calyx and corolla are primary reproductive organs of the flower, while androecium and gynoecium are accessory organs. Select the correct option:
Statement I is correct. Statement II is incorrect because calyx and corolla are accessory (non-reproductive) organs, whereas androecium and gynoecium are the primary reproductive organs of the flower.
Question 140 of 300
📘 CLASS XI
Assertion (A): In hypogynous flowers, the ovary is said to be superior. Reason (R): In hypogynous flowers, the gynoecium occupies the highest position on the thalamus, while the calyx, corolla, and androecium are situated below it.
In a hypogynous flower, the gynoecium is situated at the highest position on the thalamus, and the other floral whorls arise below it. Because of this arrangement, the ovary is termed superior, as seen in mustard, china rose, and brinjal.
