Answer:
The most reduced size gametophyte is found in angiosperms, which are flowering plants. The detailed solution for this is as follows:
Angiosperms and Gametophytes:
- Angiosperms are a group of plants that produce flowers and fruits. They are the most diverse and widespread group of plants on Earth.
- In the life cycle of angiosperms, the gametophyte generation is highly reduced and dependent on the sporophyte generation.
- The male gametophyte, known as pollen grains, consists of just a few cells, including two sperm cells.
- The female gametophyte, also called the embryo sac, is composed of only a few cells, including the egg cell.
Gametophytes in Other Plant Groups:
- Bryophytes, which include mosses, liverworts, and hornworts, have larger and more complex gametophytes compared to angiosperms.
- Pteridophytes, such as ferns and horsetails, also have larger and more independent gametophytes compared to angiosperms.
- Gymnosperms, which include conifers and cycads, have reduced gametophytes compared to bryophytes and pteridophytes but are still larger than those of angiosperms.
Reasons for Reduced Gametophytes:
- The reduction in gametophyte size in angiosperms is believed to be an evolutionary adaptation that allows for more efficient reproduction.
- The smaller gametophytes in angiosperms are better protected and supported by the larger sporophyte generation.
- The reduced gametophytes also allow for more rapid and efficient pollen transfer, increasing the chances of successful fertilization.
Conclusion:
- The most reduced size gametophyte is found in angiosperms, which have small and highly dependent gametophytes compared to other plant groups.
- This reduction in gametophyte size is an evolutionary adaptation that allows for more efficient reproduction in angiosperms.