Test: Plant Kingdom- Pteridophytes (April 11) - NEET MCQ

The seed habit was established in Gymnosperms. The development of seed habit, seen in present-day gymnosperms (and also in angiosperms) eliminated the requirement of water during sexual reproduction. In seed plants, two types of sporangia develop on sporophylls. They are known as megasporangium (ovule) and microsporangium.  The ovule upon fertilization gives rise to the seed.  

Heterospory is a phenomenon in which two kinds of spores are borne by the same plant. These spores differ in size. The smaller one is known as microspore and the larger one is known as megaspore. The microspore germinates to form the male gametophyte and the megaspore germinates to form the female gametophyte. Heterospory evolved first in pteridophytes such as Selaginella and Salvinia. Hence option B is correct.

In Lycopsida, the sporophyte is differentiated into stem, roots and leaves. The leaves are microphyllous and with a single vein. The vascular strands or steles may be protostelic, siphonostele or polystelic. The leaf-gaps are always absent, sporophylls produce a single sporangium on the adaxial side near its base. The sporophylls are borne in strobili. They are homosporous or heterosporous. The antherozoids are biflagellate or multiciliated.
Therefore, the correct answer is option A.

The antherozoid of Lycopodium is pear shaped with two flagella at the anterior end. The biflagellate antherozoids of Lycopodium resemble more to the antherozoids of Bryophytes, rather than those of vascular plants.

The origin and evolution of the seed habit was started in late Devonian times about 385 M. a) The earliest seed plants, “progymnosperms”, emerged in the late Devonian . Progymnoperm fossils show vegetative morphologies to seed plants.