Question

Which one of the following has a haplontic life cycle?

• A. Funaria
• B. Wheat
• C. Ustilago
• D. Polytrichum

Answer 1

The correct option is C

Ustilago

The correct option is C.

The explanation for the correct option:

1. All the plants follow sexual and asexual stages of reproduction throughout their life span alternating from one phase to another, this phenomenon is referred to as Alternation of generation.
2. The asexual stage is referred to as the Sporophytic stage where diploid spores are produced
3. And Sexual stage is referred to as the Gametophytic stage, where haploid gametes (male and female) are produced.
4. When a plant has been haploid for the longest time of its lifespan, then the life cycle is referred to as the haplontic life cycle.
5. Lower groups of plants follow the Haplontic life cycle.
6. Ustilago shows a haplontic life cycle where the haploid stage is multicellular and the diploid stage is unicellular.

The explanation for the incorrect options:

Option A:

1. Funaria shows a Haplo-diplontic life cycle.
2. In this type of life cycle, Haploid gametophyte generation alters with Diploid Sporophytic generation.
3. As both haploid and Diploid generation alternates, it is referred to as the Haplo-diplontic life cycle.

Option B:

1. Wheat is an angiosperm.
2. And unlike other angiosperms, it also follows a diplontic life cycle.
3. Here Diploid Sporophyte is dominant and independent and the Haploid gametophyte is recessive and dependent on the sporophyte.

Option D:

1. Polytrichum shows a haplo-diplontic life cycle.
2. Here also, haploid and Diploid generation alternates, hence it is referred to as the Haplo-diplontic life cycle.

Final answer: Ustilago has a haplontic life cycle.