Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Morphology of Flowering Plants

Question:

Read the following statements and find out the incorrect statement.

Options:

Orchid is a non-endospermic monocotyledonous seed.

Castor is endospermic dicotyledonous seed.

In monocotyledonous seed the outer covering of endosperm separates the embryo by a proteinaceous layer called aleurone layer.

None of the above.

Correct Answer:

None of the above.

Explanation:

The correct answer is Option (4) -None of the above.

Structure of a Dicotyledonous Seed : The outermost covering of a seed is the seed coat.  Within the seed  coat is the embryo, consisting of an embryonal axis and two cotyledons. The cotyledons are often fleshy and full of reserve food materials. At the two ends of the embryonal axis are present the radicle and the plumule . In some seeds such as castor the endosperm formed as a result of double fertilisation, is a food storing tissue and called endospermic seeds. In plants such as bean, gram and pea, the endosperm is not present in mature seeds and such seeds are called non-endospermous. 

Monocotyledonous seeds are endospermic but some as in orchids are non-endospermic. In the seeds of cereals such as maize the seed coat is membranous and generally fused with the fruit wall.

The endosperm is bulky and stores food. The outer covering of endosperm separates the embryo by a proteinous layer called aleurone layer. The embryo is small and situated in a groove at one end of the endosperm. It consists of one large and shield shaped cotyledon known as scutellum and a short axis with a plumule and a radicle. The plumule and radicle are enclosed in sheaths which are called coleoptile and coleorhiza respectively.