Question

Which one of the following organisms is correctly matched with its three characteristics?
(a) Pea: ${ C }_{ 3 }$ Pathway, Endospermic seed, Vexillary aestivation
(b) Tomato: Twisted aestivation, Axile placentation, Berry
(c) Onion: Bulb, Imbricate aestivation, Axile placentation
(d) Maize: ${ C }_{ 4 }$ Pathway, Closed vascular bundles, Scutellum

Answer 1

Hint: Kranz anatomy is a specialized structure in ${ C }_{ 4 }$ Plants where the mesophyll cells are clustered around the bundle-sheath cells in a ring- like fashion. ${ C }_{ 4 }$ plants include important human food crops like sugarcane, sorghum, etc. The scutellum is thought to be a modified cotyledon, or seed leaf, which is found mostly in grains or cereals.

Complete answer:
Maize plant shows Kranz anatomy, with ${ C }_{ 4 }$ cycle. Does not exhibit secondary growth. So, the closed vascular bundle has a single cotyledon which is called the scutellum. Maize is a tall annual grass, having an erect, joined, and solid stem which varies widely in height. Leaves are alternate, long and narrow, with wavy margins. The plant is monoecious. The main stalk terminates in a staminate male inflorescence, called the tassel. It consists of many small flowers or spikelets, each having three small anthers which produce pollen grains.

Additional Information:
- Pistillate inflorescence develops in variable numbers from one to three or even more per plant in the axils of some lower leaves.
- It is a spike with 8- 36 rows of spikelets, which are born on a hard and thick cylindrical core, called a cob. The whole inflorescence is enclosed in modified bracts, called husks or shucks.
- The Pistillate spikelets are sessile and occur in pairs of one fertile and the other sterile floret. The floret develops an ovary in the center. Each fertilized ovary develops to the kernel and the pistillate spike matures to the ear.
So, the correct answer is ‘(d) Maize- ${ C }_{ 4 }$ pathway, closed vascular bundle, scutellum'.

Note:
- C4 plants—including maize, sugarcane, and sorghum, avoid photorespiration by using another enzyme called PEP during the first step of carbon fixation.
- ${ C }_{ 3 }$ plants are plants in which the initial product of the assimilation of carbon dioxide through photosynthesis is 3- phosphoglycerate, which contains 3 carbon atoms.
- ${ C }_{ 3 }$ plants include the cereals barley, oats, rice, and wheat, alfalfa cotton, Eucalyptus, sunflower, soybeans, sugar beets, potatoes, tobacco, Chlorella, and others.