Question 12
Ferns are spore-bearing vascular plants (pteridophytes) with no flowers or fruits. Their life cycle alternates between the spore-producing sporophyte (called the asexual phase here) and gamete-producing gametophyte (sexual phase).
I. Spore bags burst, spores fall to soil and germinate into young gametophytes or prothalli.
II. Rootlike rhizoids grow from the gametophyte’s lower surface and anchor it.
III. Mature gametophytes develop sperm-producing and egg-producing structures.
IV. With enough water, sperm-containing structures release sperm; a sperm swims to fertilize an egg, forming a zygote within the gametophyte.
V. The young plant roots in soil and the gametophyte disintegrates until only the new plant remains.
Anita is surprised when ferns sprout among her sunflower plants. Which stage is responsible?
I. Spore bags burst, spores fall to soil and germinate into young gametophytes or prothalli.
II. Rootlike rhizoids grow from the gametophyte’s lower surface and anchor it.
III. Mature gametophytes develop sperm-producing and egg-producing structures.
IV. With enough water, sperm-containing structures release sperm; a sperm swims to fertilize an egg, forming a zygote within the gametophyte.
V. The young plant roots in soil and the gametophyte disintegrates until only the new plant remains.
Anita is surprised when ferns sprout among her sunflower plants. Which stage is responsible?