Question

Ovule in which funicle, chalaza and micropyle occur in one vertical plane___________is
A. Anatropous
B. Orthotropous
C. Amphitropous
D. Campylotropous

Answer 1

On the basis of its orientation, form and position of the micropyle with respect to funicle and chalaza, ovules are classified into six types, namely orthotropous, anatropous, hemianatropous, amphitropous, campylotropous and circinotropous.

Complete answer:
The orthotropous ovule is also called anatropous ovule. It is the most primitive type of ovule. In this type of ovule, the micropyle is at the distal end and the micropyle, the funicle and the chalaza lie in one straight vertical line. This type of ovule is found in the members of the family Piperaceae, Polygonaceae.

Thus, option B. Orthotropous is the correct answer.

Additional information:
In an anatropous ovule, the body of the ovule is completely inverted. As a result the micropyle and funiculus come to lie very close to each other. This is the common type of ovules found in dicots and monocots. In a hemi anatropous ovule, the body of the ovule is placed transversely and at right angles to the funicle. In campylotropous, the body of the ovule at the micropylar end is curved and more or less bean shaped. In an amphitropous, the distance between hilum and chalaza is less. In a circinotropous ovule, the funiculus is very long and surrounds the ovule as in cactus.

Note: Ovule is also called megasporangium which is covered by one or two integuments. A mature ovule consists of a stalk or funicle and a body. Integument encloses the nucellus completely except at the top where it is free and forms a pore called micropyle. The opposite end of micropyle end is called chalaza. Form and position of the micropyle with respect to funicle and chalaza, ovules are classified into different types.