Question

Union of stamens with carpels form a complex called
(A) Gynostegium
(B) Syngenesious
(C) Gynandrium
(D) None of the above

Answer 1

Hint: In flowers the gynoecium is the female reproductive organ of the plant where the androecium is the male reproductive organ. The gynoecium includes style, stigma, ovary and ovule. The androecium includes anther, filaments and pollen grains of the flower.

Complete Answer:
Gynostegium is defined as the unit in which the stamens, style and the stigmatic surface of the carpels are united together. This is the specialized cap-like tissue which acts as the protective membrane for the gynoecium by covering it.

This is mainly common in the plants of the Asclepiadaceae. Syngenesious is defined as the condition in which the filaments are left free but the anthers are fused to the tubular mass as the single unit. This type of arrangement is found in the plants belonging to the family of the asteraceae.
The sunflower, dahlia etc. are included in this family. Gynandrium is the condition in which the stamens are united along the length. This is the combined structure of the male and female stamens. Hence in the gynostegium, the stamens and the carpels form the complex.

Thus, the option (A) is correct.

Note: The condition of the gynostegium is present in the plants that come under the family of Asclepiadaceae. These are also called milkweed. They possess the leafless stem. Asclepius syriaca, Ceropegia stapeliiformis, Burkina Faso, Microloma calycinum etc. are included in this family.