Question

Which of the following is an example of Negative Photoblastic seed?
A. Onion
B. Lily
C. Nigella
D. All of the above

Answer 1

Hint:-A seed is an embryonic plant produced as a result of the ripening of the ovule. After fertilization with the pollen, the ovule undergoes some growth to form the seed. It is produced as a result of reproduction. The embryo present in the seed is produced from the zygote whereas the integuments of the ovule form the seed coat.

Complete Answer:-The process of germination of seed results in the formation of a seedling from a seed embryo. For this purpose, the metabolic pathways are reactivated to form radicle and plumule that eventually gives rise to the root and shoot of the plant respectively. As the end result, the plant is grown out from the surface of the soil which is known as the seedling establishment.
The germination of the seed is also influenced by the presence or absence of sunlight. The seeds in which germination is stimulated in the presence of sunlight are known as positively photoblastic, whereas the seeds in which germination is inhibited in the presence of sunlight are called negatively photoblastic. These responses of the seed germination towards the sunlight are mediated by the phytochrome. Negatively photoblastic seeds are grown best in the dark while in the presence of sunlight; their growths are inhibited and so lose their ability to grow out of the surface of the soil. Examples of the plants that are negatively photoblastic are onion, nigella, and lily.

Thus the correct option is (D) All of the above.

Note:- The general meaning of the word ‘seed’ is anything that can be sown. Thus other parts of the plant (apart from the ovule) such as tubers of potatoes can also be called as seeds as it also gives rise to a new plant.