NEETBotanyPlant Kingdom
The precursor to the seed habit is observed in some pteridophytes. In gymnosperms, which of the following characteristics is directly responsible for the definitive establishment of the seed habit?
Options
- AThe aggregation of sporophylls to form distinct and compact strobili or cones
- BThe retention of the female gametophyte within the megasporangium on the parent sporophyte
- CThe development of needle-like leaves with thick cuticles and sunken stomata
- DThe dispersal of microspores by wind currents for pollination
Correct answer
B. The retention of the female gametophyte within the megasporangium on the parent sporophyte
Step-by-step solution
The seed habit is considered an important step in plant evolution. Its precursor is seen in heterosporous pteridophytes (like Selaginella and Salvinia) where the female gametophyte is retained on the parent sporophyte for variable periods. In gymnosperms, this evolutionary step is fully established. The female gametophyte does not have an independent free-living existence; it is permanently retained within the megasporangium (ovule) on the parent sporophyte. Fertilization and the subsequent development of the zygot