Plant Reproduction and Germination

An unfertilized ovule contains the embryo sac (female gametophyte), which is a generation within the sporophytic tissue of the ovule.

A. Nymphaea- Reserve food material in perisperm (Persistant nucellus). Perisperm occurs in the seeds of black pepper, coffee, castor, cardamom, Nymphaea. It is diploid.

B. Coconut- Reserve food material in endosperm.

C. Onion- Reserve food material in endosperm

D. Litchi- Reserve food material in cotyledons.

So, the correct answer is 'Nymphaea'.

The process of induction of flowering in plants, by exposing seeds at low temperature for prolonged periods is called Vernalisation. It is an aerobic, temperature dependent phenomena, prevents precocious reproductive development. It does not depend on light.

So, the correct answer to the question is ‘vernalisation is not a light dependent phenomena’.

Vernalization is the acquisition of a plant's ability to flower in the spring by exposure to the prolonged cold of winter, or by an artificial equivalent. Many plants grown in temperate climates require vernalization and must experience a period of low winter temperature to initiate or accelerate the flowering process. This ensures that reproductive development and seed production occurs in spring and summer, rather than in autumn.

Vernalization if the process of artificial induction of plant's flowering process which is discovered by Gassner and flowering time also changed by external factors.

Vernalization is the process by which plant can be induced to flower by exposing it to the prolonged period of low temperature or cold. After this, plants show quicker flowering. The term was coined by Lysenko in 1928. He stated that certain plants can be made to flower by providing low temperature treatment to young plants or semigerminated seeds.

Vernalization is the artificial exposure of plants to low temperatures in order to stimulate flowering or to enhance seed production. By satisfying the cold requirement of many temperate zone plants, flowering can be induced to occur earlier than normal or in warm climates lacking the requisite seasonal chilling.

Vernalisation is the phenomena in which flowering is induced in the plant by exposing it to low temperatures. Seeds of winter varieties will flower only when they are exposed to cold period early in their development. Artificially, flowering can be induced in spring as well if they are exposed to artificial vernalization. 

Photoblastic seeds require wavelength in the range of 660nm for the germination of seeds. Out of the two forms of phytochrome, Pr form absorbs light of 660nm wavelngth. It stimulates germination.

Seed germination requires sufficient amount of P$ _pr$fr. P$ _r$ is synthesized by germinating seeds and is converted to P$ _pr$ when exposed to red light. However, when  seeds are exposed to far-red light, they will not germinate as P$ _r$ is converted to P$ _r$.

Phytochromes are the hormones that are light dependent and are bluish green pigments that are involved in the developmental processes. They are light dependent and activates the inactivated form of phytochrome. They sometimes are useful in seed germination and cell elongation but stops the elongation of the stem when getting too exposed to far-red light and get inactivated.

Vivipary means that seed remains attached to the plant even during germination. It is an undesirable character for annual crops as they are not able to store under normal condition for coming years.

Sexual reproduction involves the formation of haploid gametes. The gametes are produced by a specialised type of cell division called meiosis. The meiosis is a special type of division because it is reductional division and it involves crossing over. The crossing over involves the exchange of chromosomal segments between non-sister chromatids of a homologous pair of chromosome. The crossing over results in new genetic combinations. The rearrangement of genetic material every time crossing over occurs produces new combinations thus leading to the generation of variations in a sexually reproducing population.

Vegetative propagation is a form of asexual reproduction where plants grow from vegetative parts like stems, roots, or leaves without seeds. Since asexual reproduction is the broader category that includes vegetative propagation, both options A and C are correct.

Scattering of seeds ensures the spread of species over the maximum area which protects it and it also prevents the growth of the same plant at one place and reduces the competition of food and other resources hence reduces competition and over-crowding.