Question

Double fertilization was discovered by Nawaschin in
A. Polygonum, Magnolia
B. Lilium, Polygonum
C. Fritillaria, Lilium
D. Fritillaria, Peperomia

Answer 1

Hint: Double fertilization was first explained in 1898 by Nawaschin in two liliaceous plants. Double fertilization is a characteristic feature of angiosperms.

Complete step-by-step answer:
Sergius Nawaschin explained for the first time about double fertilization in Fritillaria tenella and Lilium martagon plants. Double fertilization is a reproductive event seen exclusively in angiosperm that involves triple fusion during fertilization. The triple fusion includes the fusion of a sperm with an egg cell to form the zygote, which is followed by the fusion of two more sperms with the polar nuclei that give rise to endosperm.
Correct option is C Fritillaria, Lilium

Additional Information:
1) Double fertilization involves the first fertilization of one haploid male gamete fusion with a haploid female gamete to form a diploid zygote. This process is known as syngamy. The 2nd fertilization event involves the fusion of nucleus of two haploid male gametes with two polar nuclei (haploid)or a secondary nucleus (diploid) of the central cell in the ovary that forms a triploid PEN (primary endosperm nucleus). 2nd fertilization is also known as vegetative fertilization. Also, the central cell involved in 2nd fertilization is called as PEC (primary endosperm cell).
2) Double fertilization has an advantage over normal fertilization as it helps the angiosperms in energy conservation. As the sperm fertilized polar nuclei forms endosperm that develops and stores nutrients and so the plant does not have to spend energy on resources towards the synthesis and storage of nutrients for an egg.

Note: Product of normal fertilization is a zygote, but in double fertilization in addition to zygote, an endosperm is also formed. Double fertilization is usually seen in angiosperm, the flower-bearing plants that have both male and female reproductive parts (male and female gametophytes) on the same flower.