Question

Which one of the following organisms is correctly matched with its characteristics?
A. Tomato- Twisted aestivation, axile placentation, berry
B. Onion- Bulb, imbricate aestivation, axile placentation
C. Maize- ${C_3}$ pathway, closed vascular bundles, scutellum
D. Pea- ${C_3}$ pathway, endospermic seed, vexillary aestivation

Answer 1

Aestivation is the arrangement of sepals or petals in a floral bud, pertaining to the members of the same whorls in the flower. Placentation is the arrangement of the placentae containing the ovules in the ovary. In the case of ${C_3}$ plants, the fixation of a single molecule of $C{O_2}$ utilizes 3 ATP and 2 NADPH, while in ${C_4}$ plants, the fixation of a single molecule of $C{O_2}$ utilizes 5 ATP and 2 NADPH molecules.

Complete answer:
A. Tomato- Twisted aestivation, axile placentation, berry.

The tomato plant possesses valvate aestivation, i.e., margins of adjacent petals or sepals only touch each other but do not overlap, the placentation is of axile type, i.e. the ovary is segmented by radial spokes with placentas present in the separate locules and fruit is of berry or capsule type.
B. Onion- Bulb, imbricate aestivation, axile placentation
Onion has a bulb which is the modified stem, the aestivation is of imbricate type i.e., if the margins of sepal and petals overlap one another but not in any one particular direction, the placentation is of axile type i.e. the ovary is partitioned by radial spokes with placentas present in separate locules.
C. Maize- ${C_3}$ pathway, closed vascular bundles, scutellum
In the case of the maize plant, the dark reaction follows the ${C_4}$ pathway, the vascular bundle is of open type, and in seed scutellum, which is a modified seed lea, is present.
D. Pea- ${C_3}$ pathway, endospermic seed, vexillary aestivation
In the case of the pea plant, the dark reaction follows the ${C_3}$ pathway, the seed of the pea plant is non-endospermic, the aestivation is valvate or imbricate type.

So, the right answer is option B.

Additional Information:
Aestivation or estivation in plants is the positional arrangement of different parts of a flower in a flower bud before opening. Aestivation is also called prefoliation, which can also denote vernation i.e. the arrangement of leaves in a vegetative bud.

Note: Placentation is the arrangement of the placentae containing the ovules in the ovary. It is of five types: Marginal: e.g., pea, Axile: e.g., tomato, Parietal: e.g., mustard, Free central: e.g., chilly, Basal: e.g., sunflower.