Enumerate any five characteristic features of Gymnosperms.
Answers
Answer:
⑤❭ Level of all evolution is primitive group of seed-bearing plant. ⑥❭ Xylem lacks vessels & Phloem lacks companion cell. ①❭ They produce flower & seeds. ②❭ Seeds are enclosed by the fruit wall.
The gymnosperms are naked seeded plants Gymnosperms include medium-sized trees or tall trees and shrubs.
Roots in some genera have fungal association in the form of mycorrhiza (Pinus), while in some others (Cycas) small specialized roots called coralloid roots are associated with N2- fixing cyanobacteria.
The stems are unbranched (Cycas) or branched (Pinus, Cedrus). The leaves may be simple or compound.
The leaves in gymnosperms are well-adapted to with stand extremes of temperature, humidity and wind.
In conifers, the needle-like leaves reduce the surface area.
Their thick cuticle and sunken stomata also help to reduce water loss.
The gymnosperms are heterosporous; they produce haploid microspores and megaspores.
The two kinds of spores are produced within sporangia that are borne on sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones.
The strobili bearing micros porophylls and micros porangia are called micros porangiate or male strobili.
The micros pores develop into a male gametophytic generation which is highly reduced and is confined to only a limited number of cells.
The cones bearing megasporophylls with ovules or megasporangia are called macros porangiate or female strobili.