Entrance Exams
Govt. Exams
After fertilization, the zygote undergoes mitosis to form suspensor and embryo proper, which together develop into a seedling after germination.
Ring arrangement of vascular bundles, cork cambium, and secondary growth are characteristics of dicot gymnosperms like Pinus and Cedrus.
The integument of the ovule develops into the seed coat (testa), which protects the embryo and endosperm in seeds of both gymnosperms and angiosperms.
In double fertilization, one sperm nucleus fuses with the egg nucleus to form diploid zygote (embryo), while the second sperm fuses with the two polar nuclei to form triploid endosperm.
The prothallus is the free-living, independent, heart-shaped gametophytic generation in ferns that produces archegonia and antheridia.
Naked ovules (not enclosed in ovary) and cone formation are characteristic features of gymnosperms. Angiosperms have ovules enclosed in the ovary.
Selaginella exhibits heterospory (producing two types of spores) and possesses a ligule (a small appendage), which are absent in Lycopodium.
The gametophyte generation is always haploid (n) because it develops from spores after meiosis and produces gametes through mitosis.
Gymnosperms possess the most advanced vascular tissue with secondary growth, vessels in some species, and efficient water transport mechanisms compared to other groups.
In typical polygonum type, a functional megaspore undergoes three mitotic divisions producing an 8-nucleate, 7-celled embryo sac (3 antipodal, 2 synergid, 2 polar nuclei, 1 egg).