Chapter 23, Problem 11STP

Summary Introduction

To write:The chromosome number of the prothallus.

Introduction:Ferns belong to the Pterophyta division and is characterized by flowering plants with leaves from subterranean, creeping rhizomes. The leaves are grown in tree ferns on a certain woody trunk. The diploid, leaf-bearing sporophyte is the main component of the life-cycle. Rows of brown sori are at the underside of the branches. Each sorus is composed of a sporangia cluster.

Explanation of Solution

Spore Mother cells undergo meiosis within the sporangium, creating multiple haploid spores.Each spore germinates and becomes a heart-shaped gametophyte known as prothallus.The haploid gametophyte contains sex organs (antheridia and archegonia), both male and female. As per gametophyte species, ferns are usually monoecious on the same gametophytes, with male and female sex organs. Antheridia produce flagellated sperm that need water to move to archegonia.

Conclusion

Thus, it concludes that if the chromosome number in fern is 14 then the chromosome number of the prothallus would be 7.