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प्रश्न
Briefly comment on the significance of heterospory.
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उत्तर
- The male gametophyte releases the male gametes and these reach the female gametophyte to fuse with the egg. The development of the zygote takes place inside the female gametophyte.
- This retention and germination of the megaspore within the megasporangium ensures proper development of the zygote. The zygote develops into the future sporophyte. The evolution of the seed habit is related to the retention of the megaspore.
- Heterospory is thus considered an important step in evolution as it is a precursor to the seed habit.
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संबंधित प्रश्न
Differentiate between the following:
Homosporous and heterosporous pteridophytes
Which one of the following belongs to vascular cryptogams?
In the prothallus of vascular cryptogram, the antherozoids and eggs mature at different times. As a result,
Genera like Selaginella and Salvinia produce two kinds of spores. Such plants are known as ______
The main plant body in Pteridophyte is ______.
A Prothallus is ______.
Heterospory i.e., formation of two types of spores – microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in plant kingdom?
How far does Selaginella one of the few living members of lycopodiales (pteridophytes) fall short of seed habit.
How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
Gametophyte is a dominant phase in the life cycle of a bryophyte. Explain.
Given below are the stages in the life cycle of pteridophytes. Arrange the following stages in the correct sequence.
- Prothallus stage
- Meiosis in spore mother cells
- Fertilisation
- Formation of archegonia and antheridia in gametophyte.
- Transfer of antherozoids to the archegonia in presence of water.
Choose the correct answer from the options given below:
