In circinotropous ovule

Detailed Solution

The correct answer is d). the body of ovule becomes inverted and again turned into straight position due to the growth of funiculus so that body of ovule is present on funicle at 3600.

Let's get deeper into the concept of ovule orientation:

• Ovule Orientation: In flowering plants, the ovule, which houses the female gametophyte (embryo sac), exhibits various orientations. These orientations are crucial for successful fertilization and seed development.
• Circinotropous Ovule: As the name suggests, "circinotropous" implies a circular or revolving movement. In this type, the ovule undergoes a complex series of rotations. Initially, the ovule body may become inverted. Subsequently, the funiculus (stalk attaching the ovule to the placenta) elongates and curves, causing the ovule to rotate back to its original position. This intricate movement results in the ovule body being positioned at a 360-degree angle relative to the funiculus.
• Other Ovule Types:
  • Orthotropous: This is the simplest type where the micropyle, chalaza, and hilum (point of attachment to the funiculus) lie in a straight line.
  • Anatropous: The most common type. The ovule undergoes a 180-degree rotation, so the micropyle and hilum are brought close together.
  • Hemianatropous: The ovule is bent at a 90-degree angle to the funiculus.

Understanding these ovule orientations is crucial in plant developmental biology and has implications for seed production and plant breeding.