Question

All vascular plant groups show similarity in

• A. having a dominant gametophyte phase
• B. having an independent sporophyte
• C. requirement of water for gamete transfer
• D. producing motile male gametes

Answer 1

The correct option is B having an independent sporophyte

Vascular plants include pteridophytes, gymnosperms and angiosperms. Apart from having the vascular tissue in common, all these plants exhibit similarity in having an independent and dominant sporophyte.

Pteridophytes have an independent gametophytic phase but it is not the dominant phase of the life cycle.

Gymnosperms and angiosperms have highly reduced gametophytes, that are dependent upon sporophyte.

Male gametes are motile in pteridophytes and few gymnosperms like Cycas and Ginkgo. In angiosperms, male gametes are non motile and are carried to the female gamete by the pollen tube. Water is required for gamete transfer in pteridophytes. In aquatic angiosperms (hydrophytes), water is used as a medium of transfer of the pollen grains (consisting of male gametophyte) to the stigma (pollen grain receptor) of the flower. The pollen grains carry the two male gametes in them. In gymnosperms and the majority of the angiosperms, pollen grain transfer is either by wind or some animals.