Which of the following is characteristic feature of fern: i) Ferns have seeds ii) Plant body is differentiated into root, stem and leaves. iii) They have tuberous roots iv) Ferns are gametophytes Which of the following is correct:
(a) (i) and (ii) (b) Only (i) (c) Only (iii) (d) All of them are true
Hint: These come under vascular plants which are generally known as cryptogram. vascular tissue was first observed in these plants. vascular tissue means the xylem and phloem. Found in cool, damp and shady places.
Complete answer: Cryptograms are also known as pteridophytes. The dominant phase in these plants are sporophyte. Which means a diploid multicellular stage in the present life cycle of a plant. Main body is differentiated into true stem, leaves and roots. Found in cool, damp and shady places because of the need for water for fertilisation.
This plant type lacks seeds. The leaves are microphylls which means large, as in ferns. The leaflets and leaves having sporangia are called sporophylls. The sporangia contain sporogenous tissue, where spore mother cells undergo sporic meiosis to produce spores. Plants like lycopodium, dryopteris, etc .produce a single kind of spore and hence are homosporous. This means only one kind of spore is produced. Some plants like selaginella and salvinia, possess micro and macro size of spores, and are termed as heterosporous.
The spore germinates to give rise to inconspicuous, small but multicellular free living, mostly photosynthetic thalloid gametophytes called prothallus. Further, the megaspore and microspore develop and give rise to female and male gametophyte respectively.
Hence the correct answer is option (a)
Note: They help in soil binding even in hill slopes.it protects the soil from soil erosion. In medicine an anthelmintic drug is obtained from a pteridophyte called dryopteris. Ferns are also grown as ornamental plants for their delicate and graceful leaves.