Class 12 Biology Reproduction Sexual Reproduction in Flowering Plants



In Ricinus, the outer white papery covering of endosperm is

(a)
Perisperm/tegmen
(b)
Tigellum
(c)
Strophiole
(d)
Exo-endosperm
Correct answer: (a) 
Solution: 

Ricinus communis, the castor bean or castor oil plant, is a species of perennial flowering plant in the spurge family, Euphorbiaceae. Castor seed is a monocot, endospermic seed. A castor seed has following parts:

(i) Testa: It is the outer layer of seed coat. It is thick, hard and brittle. The external surface appears smooth, shinning and mottled brown in colour.

(ii) Tegmen: It is the inner layer of seed coat that appears dull and papery. Now it is called as perisperm or persistent nucellus.

(iii) Caruncle: It is a white spongy bilobed outgrowth present near the narrow end of the seed.

(iv) Raphae: It is a shallow ridge present on the testa of flat surface of the seed. The distinct bifurcation of raphae represents chalaza.

(v) Endosperm: It is a white oily food storage tissue that is present inner to the perisperm. From this layer castor oil of commerce is extracted.

(vi) Embryo: Embryo lies in the centre of endosperm. 

So, the correct answer is ‘Perisperm/ Tegmen’.


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Similar topics
sexual reproduction in flowering plants
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Connecting you to a tutor in 60 seconds.
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sexual reproduction in flowering plants
reproduction in organisms
evolution
human reproduction
reproductive health