Question

What is the characteristic of amphitropous ovule?
A. Body is straight but the embryo sac is curved
B. Body of ovule, as well as embryo sac, are curved
C. Body of ovule is curved but the embryo sac is straight
D. The funiculus is coiled over the body of ovule

Answer 1

Hint: The ovules are categorized based on their shapes. The names come from the relative alignment chalaza, funicle, and micropyle to the embryo sac. The amphitropous ovule becomes horseshoe-shaped due to curvature.

Complete answer:
The ovules in angiosperms can be categorized into six groups based on their shapes. Let’s check each of them.
Orthotropous/Anatropous – These kinds of ovules have their micropyle, funicle, and chalaza in a straight line. Examples include Polygonaceae, Piperaceae, etc.
Anatropous – Here the micropyle lies very close to the hilum because the body of the ovule is completely inverted during development. It is the most common type of ovule in angiosperms. Examples are Gamopetalae members.
Hemitropous – The micropyle and chalaza are in a straight line in this. But the body of the ovule is transversely placed at a right angle to the funicle. An example is Ranunculus.
Campylotropous – Here the body of the ovule is curved. This results in the micropyle and chalaza being not aligned in a straight line. Examples are Leguminosae members.
Circinotropous – In this type, the nucellus and axis are in a straight line alignment in the beginning. Later the ovules become similar to anatropous due to rapid growth in the sides. Examples are Cactaceae members.
Amphitropous – The body of the ovule is curved so much that it induces curvature in the embryo sac. Examples are Lemna, Poppy, Alisma, etc.

For an amphitropous ovule, the Body of the ovule as well as the embryo sac are curved.So, the correct answer is option ( B ).

Note:
Let’s break down each name to reach the answer quickly by educated guesses. (–Tropous means curved). Ortho- Straight, A- not, Ana- Backward, Hemi- Half, Campylo- Curved, Circino – Make round, Amphi- Both. Now it is easy to see that in amphitropous, both bodies of ovule and embryo sac are curved.