Question

In ginkgoales the male gametes are
A. Motile
B. Non-motile
C. Amoeboid
D. Absent

Answer 1

Hint:-Ginkgoales in Gondwana have a long fossil record. These are large trees distinguished by long shoots and short shoots. They have wood with a small pith, helical branching proliferates and leaves are born in a helical arrangement.

Complete Answer:-Usually, leaves on long shoots are widely spaced while those around the apical portion are clustered on the short shoots. They are distinctive, fan-shaped, bilobed, or often strongly dissected, with dichotomous branching veins. They are distinctive, fan-shaped, bilobed, or often strongly dissected, with dichotomous branching veins. Ginkgo biloba, with its female and male trees, is dioecious. On the short shoots, the ovules and microsporophylls are terminal and are born. The ovules are born on the ovulate axis in tiny cups. Of the two ovules usually present in established Ginkgo, only one reaches maturity. With an outer fleshy layer, the ovules and mature seeds are relatively large.
Based on some reproductive characteristics such as flagellated male gametes, it was thought to be closely related to members of the Cycadales. The collar that covers the mature seed has been a central topic in addressing the evolution of the reproductive organ. Developmental studies of Ginkgo ovules indicate that after the integument has formed and lacks vascular tissue at maturity.
Ginkgoales, which are part of the gymnosperm division, have reproductive organs in the form of cones or strobili. Although the male cones are composed of microsporophylls, the megasporophylls are composed of female cones. Microsporophylls hold microsporangia and a large number of microspores or grains of pollen, which form the male gametophytes later on. The male gametes in them are motile.

Hence, the correct answer is (a) Motile

Note:- In Gondwana, Ginkgoales have a long fossil record, beginning at least as early as the Cisuralians. In connexion with a cooler temperature interval, Ginkgoales returned to the Gondwanan flora in the Aptian in moderate abundance.