Question

Thirty seeds, each of Dolichus, Pisum, and maize are kept for germination in the soil. How many cotyledons are found above the soil and below the soil respectively when all the seeds germinate?

• A. 60, 60
• B. 60, 90
• C. 90, 90
• D. 30, 60

Answer 1

The correct option is D 30, 60

The availability of favorable conditions (both external and internal) ensures that seeds germinate. Germination can be

1. Epigeal, where a straight radicle comes out and fixes the seed to the soil with the secondary roots coming out of the radicle. The hypocotyl grows to form a loop which comes out of the soil and pulls out the rest of the seed. The seedcoat gets caught to a peg-like projec­tion at the base of the hypocotyl and the cotyledons are brought out in the air. For example, Dolichus lablab
   
2. Hypogeal, where the radicle comes out first, penetrates the soil and forms a root system by giving out secondary branches. The epicotyl grows first which arches out and carries the plumule above ground. The plumule soon forms the aerial shoot. The cotyledons, therefore, remain under soil throughout as is shown in Pisum and Maize. However, at the time, these also tend to show epigynous germination.
   

So, out of 90 seeds in total (thirty each of Dolichus, Pisum and Maize), 30 seeds of Dolichus show epigeal germination with cotyledons above the soil and the rest 60 show hypogeal germination.